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PMD-1000 User Manual

1. LCananal Dhntaniec D GP ETHERNET SETUP Sitti UI ft mvEewvitives Serial Port Baud Rate Port Configuration coma 28800 Note RS 232 baud rate must be 28800bps GET IP CONFIG MODE SETTING STATIC IP SETTING Select DYNAMIC Mode ETHERNET MODE Select STATIC Mode STATIC STOP Program Ethernet mode selection screen static Clicking the OK button for dynamic mode puts the PMDPro into dynamic IP mode The instrument will obtain the dynamic IP information from the server When it is finished the indicator for dynamic mode will turn green and the Ethernet Mode status box will say DYNAMIC Clicking the OK button for static mode puts the PMDPro into static IP mode The instrument will recall the static IP settings from its memory These can then be used for communication When it is finished the indicator for static mode will turn green and the Ethernet Mode status box will say STATIC The PMDPro writes its most recently saved static IP settings and its active mode to memory If it is powered off while in static mode when it is powered back on it will be in static mode and the most recently saved set of IP configuration information can be used for communication If the PMDPro is powered off while in dynamic IP mode when it is powered back on it will be in dynamic IP mode The third tab in the program STATIC IP SETTING allows
2. This is the calculation screen To select a DGD SOPMD pair to be matched and stored use the left and right arrow keys to move the cursor to the DGD and SOPMD positions and the up and down arrows to change the values As soon as one of the values is changed the screen changes to edit mode A Cts Edit Loc 00 DGD 29 90 SO _ 300 0 After editing the DGD and SOPMD values press the ENTER key The PMDPro returns to the calculation screen and shows the calculated values that most closely match the requested ones A Cts Calc Loc 00 DGD 30 07 SO 270 0 If the calculated values are acceptable move the cursor to the Loc position set the desired memory location and press ENTER The PMDPro will store the current set of DGD SOPMD values to the selected memory location and increment the memory location by 1 2 PMDC RESULT This option allows the user to store PMD compensation data from any of the PMDPro s PMD compensation functions After obtaining the PMDC result press the STORE button and select the PMDC STORE RESULT option The top line of the screen will display the DOP measured by the input I and output O polarimeters at the end of the last PMD compensation run The bottom line will display the PMD index number ID used for the PMD compensation and the current memory location MEM Lo DOP I 37 2 O 98 4 S ID 18 MEM Lo 0 Use the arrow keys to select the desired memory location index range 0 99 and pr
3. CV5 CV6 PMDC MODE PMC STA Query PMDC operational status END PMDC search complete RUN PMDC is still running PMC DGD OPT Scan available DGD values and optimize EO0 if successful polarization to maximize output DOP See Table 2 for other error code Scans through DGD index values 0 255 definitions PMC PMD OPT Scan available PMD values and optimize E00 if successful polarization to maximize output DOP See Table 2 for other error code Scans through PMD index values 0 6560 definitions PMC DGD CMP idn Optimize SOP to maximize output DOP at E00 if successful specified DGD value PMD ID idn Range 0 255 Ex PMC DGD CMP 16 See Table 2 for other error code definitions PMC PMD CMP idn Optimize SOP to maximize output DOP at E00 if successful specified PMD value PMD ID idn See Table 2 for other error code Range 0 to 6560 definitions Ex PMC PMD CMP 683 PMC CMP Optimize SOP to maximize output DOP at E00 if successful current PMD setting discrete or continuous See Table 2 for other error code definitions MEMORY MODE SAV DSC MBX loc id Discrete mode PMD sequence storage Store PMD ID id to memory location loc in memory Bank X Range for loc 0 to 99 Range for id 0 to 6560 Range for X A B C D or E Example SAV DSC MBE 02 36 Save PMD ID 36 to memory location 02 in Bank E SAV CON MBX loc dgd so Continuous mode PMD sequence storage Store DGD value
4. BI Direc Round trip scan The scan begins at the beginning point specified in option c proceeds to the endpoint then scans back to the beginning point UNI Direc Single trip scan The scan begins at the beginning point specified in option c scans to the endpoint and stops The PMDPro then jumps back to the beginning point to begin the next cycle Use the up and down arrows to toggle between unidirectional and bidirectional and the ENTER key to select the displayed setting f CON RATE Set the DGD variation rate in ps s for the scan Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit The variation rate range is 0 1 to 100 ps s The ENTER key selects the displayed value Document GP UM PMD 1000 21 Page 23 of 122 B STEP TRACE In step trace mode the PMDPro varies the PMD along the selected curve using a constant user selected step size and dwell time per point The setup screens for step trace mode are as follows a START stp TRACE b Rng _0 00 64 4 ps c STEP DIRECTION UP d CYCLES _ _10 Count e MODE BI DIREC 1 f STEP SIZE 04ps g DWELL __50mst STEP TRACE ONLY Use the up and down arrows to move between scan setup options and the ENTER key to access the setup screen for the selected option Options a e are the same as for continuous trace mode f STEP SIZE Set the DGD step size between points in ps Use the left and right
5. Start to start the scan While the scan is running the Scan on indicator will be green When the scan is finished the DGD and SOPMD values and the corresponding maximum output DOP are displayed in the table on the right of the screen and the maximum output DOP vs DGD is plotted in the graph The DGD value with the highest output DOP is displayed in the Measured DGD box at the top of the screen The graph serves as a measurement of both the PMD in the system and of how much of an effect PMD compensation will have The DGD value corresponding to the peak DOP in the plot is the DGD in the input signal to the PMD 1000 The height of the peak relative to the baseline DOP indicates the effect of PMD compensation After the scan is finished the data can be saved to a file by clicking SAVE DATA Data is saved as a text file with 2 columns DGD and DOP Document GP UM PMD 1000 21 Page 85 of 122 Long Term PMD Monitor This function is designed for live monitoring of PMD in a system The PMD effect in a system is a dynamic phenomenon It changes over time with changes in input polarization or environmental conditions Whereas the other PMDC functions provide a snapshot measurement of the PMD of the system at the time the measurement was taken this function allows the user to monitor the PMD effect over an extended period to characterize the behavior of the actual system It uses the lookup table DGD measurement function desc
6. Support Function includes operation setup parameters data storage and recall functions and wavelength dependence simulations When one of these buttons is clicked the corresponding operation mode screen appears in the operation area When the program is first started the default operation mode is monitor mode This screen can also be accessed by clicking the MONITOR button in the function selection panel The monitor screen has 4 sections The output power section displays the output power in dBm and mW The DGD SOPMD section displays the DGD and SOPMD currently being generated by the PMD 1000 as well as an indicator showing whether the current state is a discrete lookup table or continuous PMD state The INPUT section displays the DOP and SOP Stokes parameters measured by the PMD 1000 s input polarimeter The OUTPUT section displays the DOP and SOP Stokes parameters measured by the PMD 1000 s output polarimeter located after the PMD generating element Document GP UM PMD 1000 21 Page 57 of 122 Front Panel Functions PMDE The PMDE operation screen includes the basic discrete mode PMD generation and scanning functions PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 PMDE Erre PMD IDs WSOP 300 SOP DGD MAXWELLIAN DISTRIBUTION Scan Interval Cycle Num Average DGD a a a P Monit m ps onitor 100 m 10 10 ps Manual L e PMDC SCAN DGD
7. in the box at the top of the graph The minimum value is 0 4 s When all of the PMD values are entered into the table click Start to start the scan At each point in the scan the DGD SOPMD and maximum output DOP for that point are displayed above the graphs and the maximum output DOP vs DGD is plotted in the graph on the left The maximum output DOP for the scan and the corresponding DGD and SOPMD values are displayed below the graph The graph on the right is a 3D graph of DOP vs SOPMD and DGD It can be rotated or zoomed for viewing from different perspectives To rotate a 3D graph drag it with the mouse To zoom in or out hover the mouse over it and scroll up or down After the scan is finished the data can be saved to a file by clicking SAVE DATA Data is saved as a text file with 3 columns DGD SOPMD and DOP Document GP UM PMD 1000 21 Page 84 of 122 DGD Measurement This function scans through the DGD only states in the lookup table discrete mode and optimizes the SOP at each state to maximize the output DOP PMD 1000 182 ps Polarization Optimized PMD Source Seral Number 060 PMD Control Program Ver 2 0 Wavelength 11550 12 inm Monitor Manual Advanced PMDE PMD Meas ent Long Term PMD Monitor Setup Store Recall PMD Calculation Exit F9 heak y SRL4 INSTR Con Press Send MTN PMD 1000 R ne i a ee There are no selection parameters for this scan Click
8. 3 5 GPIB Connection 25 505 5 scisceicys ic oc cu sioceus sesso hae aad ees ea 50 4 3 6 Ethernet Come Ct i scsi ces sess 2a chased nnd edd gsr san aad se seeds 50 4 3 7 Control Program Interface cccccccccceessccesseecesseecssseecsseeeesseeeens 55 Monitor SORCOI 525 sa oc a tease alana ee cee Nanas BY RD 56 Front Panel Functions i093 sess seccsec ions esaliscet aca peinlan dott aetes adaedin eked manabdll 58 PMDE rea Reg seach ahand Asx cs obec sg oh dah oa dee een a ied na es 58 SLO Scam et Ran OR RROTE EAR TRAC So PO ETE Se MT ACU REEAT Pane Oo ME TERT et ri 61 PMDG neii e e ei aa eee cae ae ees atl te ost Oita caste 63 MONITOR ia ei a xd deren ihe TE A R E 64 MANUA E trate fas os oligos E E OEE AE A T E O ae 65 Advanced Functions 355526055 ksi BR AAG OOD REEORS 66 ADVANCED PIU ES ic coves 8 oat a eccirsv dere vaves gta veacea hs icten addedts seunsdetenactecuaadiolnts 66 PMD Measurement and Long term Monitoring 0 0 ccccccccessceeeseees 80 PMD Weasnreme nt ss 222i scscices ts Bact ste iabiiccivsesicties Batis avai entndek eeu acask 80 Long Term PMD Monitor 00 0 0 cccecccceceeseeeceeseeeceesseeeeeeseeaeeeenssaeeeenses 86 SCOUD iene Soe Sei ee et 88 Store Recalli ynna he carn Ae a gee dR aati Misael daa ak te an 89 PMD C lc lation nnen un nran A E ease eons 92 4 3 8 Remote Control Command List 0cccccccccccsscecesseecsseeecsseeeesseees 93 Section 5 Applications 0 0c cc
9. 7 088 31 42ps 0 0ps2 The DOP in the top line is the DOP measured at the output O polarimeter when the PMD SELECTED COMP function was first selected The number at the top right of the screen is the currently selected PMD index The bottom line displays Document GP UM PMD 1000 21 Page 41 of 122 the current DGD and SOPMD corresponding to the index Use the arrow keys to select the desired PMD index The PMD state updates in real time as the index is changed When the desired PMD state is selected press the ENTER key to begin polarization optimization at that state The display changes to the following screen DOP I 33 6 O 91 5 31 42ps 0 0ps2 The DOP measured at the input 1 and output O polarimeters will update in real time Use the left arrow key to stop the SOP searching and return the display to the previous index selection screen 4 2 7 Manual The manual polarization control function allows the user to tune the polarization state via direct control of the voltages applied to each of the 6 channels of the PMDPro s polarization controller It can be used to quickly find a particular SOP or for fine adjustment to optimize a worst case SOP for PMD tolerance testing When the MANUAL key is pressed the LCD displays the following set of screens V1 75 0V V2 75 0V V3 75 0V V4 75 0V V3 75 0V V4 75 0V ft V5 75 0V V6 75 0V When the cursor is on the channel selection position cursor blinking on the 1 of V1 f
10. 9 z Monitor Sean Mode 7 ndom Y pa 20 Manual 5 tH J re a 8 7 p Ti s 100 1 S SOPMD D 10 Cycle num ay ag Advanced PMDE PMD Measurement Long Term PMD Monitor Setup Store Recall PMD Calculation Generated DGD Distribution 16 Seis done ET Exit F9 PMD Scan This function set uses the quasi continuous PMD generation mode to generate two types of PMD scans The PMD trace scan creates a continuous PMD variation at a user selectable rate of change The local PMD scans generate a series or grid of PMD values with user selectable DGD and or SOPMD boundaries and step sizes PMD Trace Scan This function generates continuous PMD traces along one of the characteristic curves in PMD space Each trace is a demi arc of a characteristic curve The user can select a series of traces to be generated As each trace is configured it is added to the trace list in the upper left corner of the screen and to the graph on the right side of the screen To add a trace to the list go to the trace setting block in the middle left of the screen Select a DGD value in the Start DGD box This is the trace endpoint on the DGD axis with SOPMD 0 The DGD and SOPMD values corresponding to the other endpoint will automatically update as the start DGD is changed Clicking the Add Trace button adds the trace to the trace list and the graph To delete a trace from the list click on it in t
11. BI Directional round trip scan e g For direction UP one cycle round trip scan from lower DGD limit to upper limit and back EOO if successful See Table 2 for other error code definitions Document GP UM PMD 1000 21 Page 94 of 122 PME SCN MOD Query the scan MODE UNI For UNI Directional BID For BI Directional See Table 2 for error code definitions PME SCN STE For step trace scan Query the DGD step size in picoseconds 34 6 PME SCN STE step For step trace scan Set the DGD step size in picoseconds Range 0 1 to 64 3 ps for max range scan Maximum step size is limited by range set EOO if successful See Table 2 for other error code definitions PME SCN RTE For continuous trace scan Query the scan rate Result given in ps s 34 6 PME SCN RTE rate For continuous trace scan Set the SCAN RATE in ps s Range 0 1 to 100 0 ps s EOO if successful See Table 2 for other error code definitions PME SCN CON dgd For continuous or step trace scan Set the start DGD PMDPro will match to DGD value of closest DGD ID and calculate corresponding trace endpoint Example PME SCN CON 14 EOO if successful See Table 2 for other error code definitions PME SCN CON For continuous or step trace scan Query scan start point DGD and end point DGD SOPMD min dgd max dgd max sopmd e g 19 99 52 19 1137 9 PM
12. Maxwellian emulation Range to 999 999 EOO if successful See Table 2 for other error code definitions PME MXW SMP Query sample number setting 10000 PME MXW CYC cyc Set number of cycles to run the Maxwellian E00 if successful See Table 2 for emulation other error code definitions Range to 99 999 PME MXW CYC Query cycle number setting 1000 Document GP UM PMD 1000 21 Page 95 of 122 MAXWELLIAN MODE STATISTICAL DGD EMULATION WITH CORRESPONDING SOPMD PME EMU ENA Start PMD statistical emulation E00 if successful See Table 2 for 1 and 2 order other error code definitions PME EMU DIS Stop PMD statistical emulation E00 if successful See Table 2 for other error code definitions PME EMU AVE Query average DGD value setting for PMD dgd Units in ps Emulation Default 10 0 ps Example 23 5 PME EMU AVE dgd Set PMD emulation average DGD value E00 if successful See Table 2 for Range 90ps PMDPro 0 0ps to 30ps other error code definitions 180ps PMDPro 0 36ps to 60ps Units in ps PME EMU SMP Query number of samples for PMD emulation smp Range to 9 999 Default 100 100 PME EMU SMP smp Set number of samples for distribution E00 if successful See Table 2 for Sample Range to 9 999 other error code definitions PME EMU PMD Query current DGD and SOPMD values 23 5 235 8 Units in ps and ps during an
13. OGD Sample 5 PMDC Monitor Manual Advanced PMDE DOP vs DGD PMD Measurement Long Term PMD Monitor Setup Store Recall PMD Calculation Exit F9 y m Con Press Send to transmi command to PMD 1000 R nse Ge eee Selection parameters Average DGD average DGD value in ps for the distribution Range 0 30 ps for 90 ps PMDPro 0 60 ps for 180 ps PMDPro Sample Total number of samples to be included in the distribution Resolution Minimum index number spacing between DGD values used in the scan For example if the intrinsic DGD resolution of a 90 ps PMD 1000 is 0 357 ps and the user chooses step x2 then the DGD resolution used for the scan is 2 x 0 357 0 714 ps Resolution vstox Step x 2 Step x 4 Step x 8 Scan Mode Determines the order in which DGD values within the distribution will be generated Random DGD values are generated in random order Sorted DGD values are generated in increasing order from lowest to highest Interval dwell time in s per sample Minimum value is 0 001s However data will only be plotted for dwell times gt 1s Cycle Num Number of times to run the scan The DGD distribution plot shows the calculated distribution of DGD values that corresponds to the selected parameters This plot can be used to find a combination of average DGD and sample number that will yield a good distribution If the dwell time per point scan interval is gt 1 s th
14. PMD Emulation PMD Scan Monitor Manual Advanced PMDE PMD Measurement Long Term PMD Monitor Setup Store Recall Sano O 10 W DW SD GM 70 8 BW 100 110 120 15 140 150 160 170 160 10 20 DGD Set osz PMD Calculation Exit F9 Command y ASRL4 INSTR ra The user can select the desired DGD and SOPMD values by dragging the sliders on the plot axes by selecting or typing values in the selection boxes for each axis or by dragging the cursor a red cross to the desired point on the plot Clicking the Set button causes the PMDPro to calculate and output the closest available matches to the DGD and SOPMD chosen The indicator boxes at the top right of the screen display the calculated DGD and SOPMD values Document GP UM PMD 1000 21 Page 66 of 122 There are two methods to combine the PMD generation function with polarization control to ensure that the worst case PMD effect is found 1 To enable continuous polarization scrambling set the desired scrambling frequency either by selecting a value from the pull down menu or by typing a value in the box directly under the pull down menu and then clicking elsewhere on the screen Click the Enable Scrambling button to begin polarization scrambling This function is designed to facilitate PMD tolerance testing with polarization multiplexed signals 2 To enable automatic SOP optimization for worst case PMD effect by minimizing the output DOP click the Ena
15. PMD ID 0039 CY 0000 13 92 ps 0 0 ps2 PMD ID Index number for current DGD SOPMD pair CY number of completed cycles The bottom line displays the current DGD and SOPMD If a continuous value is stored at the current location the scan monitor screen displays PMD Contin CY 0000 23 1 ps 300 0 ps2 Again the bottom line displays the current DGD and SOPMD b SCAN PMD MEM BNK X This option specifies the memory bank to be used for the scan Use the up and down arrows to cycle through the bank labels A E and the ENTER key to select the displayed bank c BGN This option specifies the beginning memory location for the scan Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit There are 100 memory locations in each bank labeled 00 to 99 As the memory location is changed the right side of the screen displays either the ID corresponding to the PMD stored there for a discrete mode value or Contin for a continuous mode PMD value The ENTER key selects the displayed location d END This option specifies the ending memory location for the scan Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit There are 100 memory locations in each bank labeled 00 to 99 As the memory location is changed the right side of the screen displays either the ID corresponding to the PMD stored there for a discrete mode
16. Speed DOP Accuracy PDL Wavelength Dependent Loss Transient Loss Electrical Characteristics Power Supply Communication Interfaces Response Time Front Panel Display Document GP UM PMD 1000 21 2U 19 inch 3 4 rack width 3 5 H x 14 W x 14 L FC PC FC APC SC PC or SC APC 10 C to 50 C 20 C to 60 C C band or L band 5 0 dB 1550 nm 90 ps version 5 5 dB 1550 nm 180 ps version 10 to 10 dBm 50 dB 0 to 91 ps or 0 36 to 182 4 ps 90 ps range 180 ps range 0 357 ps 0 714 ps 0 1 ps 0 2 ps 2000 ps 90 ps range 8100 ps 180 ps range 1 ms minimum 2 at 2345 C 10z s 2 at 2345 C 0 45 dB typical 90 ps version 0 5 dB typical 180 ps version 0 6 dB across C band 0 6 dB typical 100 240 VAC 50 60 Hz USB Ethernet RS 232 and GPIB 1 ms typical 2 x 20 character LCD Page 5 of 122 Section 2 Overview General Photonics PMDPro is a breakthrough PMD source that can deterministically generate precise 1 order PMD up to 180 ps and 2 order PMD up to 8100 ps It combines this basic functionality with a rapid switching time 1 ms and polarization optimization capability to enable various applications related to high bit rate optical fiber communication links PMDPro simplifies and expedites all PMD related systems testing Interfacing electronics Figure 1 System diagram of polarization optimized PMD source The PMDPro contains an autom
17. Step nm 3900 Cakulate _seremo 2 1351 Jom 7 PMDC Monitor Manual THI Advanced PMDE y g lt 0 T T T T i p i 1550 5 1551 ING 154925 15195 151975 1550 1590 25 1550 5 1550 75 1551 PMD Measurement javeles inm Wevelenath nm I Ha A 3 8 Long Term PMD Monitor POCD ps2 Boe Ss Setup Store Recall mre 2600 7 p J 400 7 T i PMD Calculation 1550 15505 1551 1549 1549 5 1590 159 5 1551 Wavelength inm Wevelenath nm Exit F9 a Response a a S E Selection parameters Bits of PMDPro Discrete mode resolution of bits of the PMD 1000 By default this value is 8 DGD range DGD range of the PMD 1000 90 or 180 ps PMD ID index number for the PMD setting to be used for simulation Start WL starting wavelength in nm to be used for simulation Stop WL ending wavelength in nm to be used for simulation Step wavelength step in nm to be used for simulation Once the parameters for the simulation are selected click Calculate to run the simulation Click SET PMD to execute the setting The PMDPro s output PMD does not change until this button is clicked Exit The Exit button or the F9 function button on the keyboard exits the program Document GP UM PMD 1000 21 Page 92 of 122 4 3 8 Remote Control Command List The command list allows users to write their own programs for basic control of the PMDPro and facilitates integration with other instruments The command forma
18. Windows XP or later e 2 GB memory recommended 4 3 2 Installation Run the file setup exe This will start the installation wizard In addition to installing the control program and necessary drivers this file will install shortcuts for the remote control program on the desktop and the start menu The first installation wizard interactive screen is shown below Document GP UM PMD 1000 21 Page 46 of 122 rT LY PMDPro Software eS Destination Directory Select the primary installation directory All software will be installed in the following locations To install software into a different locations click the Browse button and select another directory Directory for PMDPro Software C Program Files x86 PMDPro Software Directory for National Instruments products C Program Files 86 National Instruments Browse Cancel lt lt Back Specify the destination directories for program files and drivers The default locations are the ones shown in the screenshot Click Next to proceed A license agreement page will appear rT LY PMDPro Software TEE License Agreement You must accept the licenses displayed below to proceed NI Ivl NATIONAL INSTRUMENTS SOFTWARE LICENSE AGREEMENT E INSTALLATION NOTICE THIS IS A CONTRACT BEFORE YOU DOWNLOAD THE SOFTWARE AND OR COMPLETE THE INSTALLATION PROCESS CAREFULLY READ THIS AGREEMENT BY DOWNLOADI
19. by the DGD value the user selects As the user changes the requested DGD value the maximum available SOPMD value will change accordingly 90ps PMDPro Maximum SOPMD determined by selected DGD N a a a a O 60 80 DGD ps Selected DGD Figure 6 DGD SOPMD range determinants for continuous control Use the left and right arrow keys to move the cursor and the up and down arrow keys to increment the digits to set the DGD and SOPMD values to be matched Note that the left and right arrow keys will scroll through all modifiable cursor positions For example pressing the right arrow key from the rightmost digit of the DGD setting line will move the cursor to the leftmost position of the SOPMD setting line Document GP UM PMD 1000 21 Page 18 of 122 When the DGD and SOPMD values are set press the ENTER key to calculate the closest available matches to the requested values If the requested SOPMD is out of range the PMDPro will flash an SOPMD out of range error message before returning to the PMD selection screen If the selected values are within range the LCD will display DGD 31 04 C 31 10 SOPMD _ 530 0 C 530 0 where the number to the right of the C on each line is now the calculated match to the requested value At this point the PMDPro has not yet changed the output DGD or SOPMD values it has only displayed the results of the match calculation If the user is satisfied with the match
20. cccccccecssccessseceeseeceeseecesseeceeseeceaeeceseeecsseeecseeecsaeees 101 5 1 PMD Tolerance Testing with Polarization Multiplexed Signals 101 5 2 PMD Mitigation in 40Gb s systems 0ccccccecccesscecesececssececeseeecssececsseees 105 Document GP UM PMD 1000 21 Page 3 of 122 5 3 Instruments required for PMD related tests 0 cccccccccccsscesessceesseceesseees 108 5 4 Desirable features for a PMD source 0 ccc cece ceteceteeeeeeeeeeeeetecnteeteeeensees 111 5 5 The polarization optimized PMD source cccccccceescceessceeeseeeesseceesseees 111 5 6 Advantages and applications of the polarization optimized PMD source 114 Section 6 Troubleshooting cccccccccccssecessseceeseeceeseecesseeceeseecsseeecseeecseeeesaeees 116 Section 7 Technical Support ccccsccccssssecssscecsscsecssscesssecesssscesssecesssecessseeesnanens 117 Appendix A ITU Grid Channel Lookup Table 000 0 ccceceeceeceeteeeteeeteetees 118 Document GP UM PMD 1000 21 Page 4 of 122 Section 1 Specifications Physical Features Dimensions Connector Type Operating Temperature Storage Temperature Optical Characteristics Typical Operating Wavelength Range Insertion Loss Input Power Range Return Loss DGD Range DGD Resolution Discrete mode Quasi continuous mode 2 order PMD Range PMD Variation Time SOP Alignment Accuracy SOP Tracking
21. confirmation screen INIT PMDE MEM BANK A INIT BANK A n y Use the ESC key to return to the Setup menu or one of the function keys to access a different menu 4 2 3 PMDE The PMDPro has two operation modes for generating PMD values The discrete mode uses digital switching to generate PMD values according to the lookup table included on the cd 6561 DGD SOPMD pairs can be accessed this way Some of the SOPMD values in this set are wavelength dependent and some are wavelength independent The wavelength dependence of any particular value in this set can be viewed using the PMD CALC function in the control program The quasi continuous PMD generation mode allows full coverage of the PMD space All PMD values generated in this mode are wavelength independent over the operation wavelength range of the PMDPro Document GP UM PMD 1000 21 Page 15 of 122 Figure 5 shows the PMD states covered by the PMDPro s discrete and continuous PMD generation modes 2500 2000 1500 1000 SOPMD ps2 500 SOPMD ps2 DGD ps a 90ps PMDPro 180ps PMDPro 2500 10000 w S amp amp Qa m z z wn 2 0 20 40 60 80 100 0 50 100 150 200 DGD ps DGD ps c d Figure 5 DGD SOPMD coverage plots a 90 ps version discrete mode b 180 ps version discrete mode c 90 ps version quasi continuo
22. control the input polarimeter is used to generate the feedback signal to control the polarization controller so the generated SOP is the SOP of the light before it enters the PMD element When the SOP key is pressed the LCD displays 5 menu options on 3 screens 1 SCRAMBLING 2 SET SOP i 3 6 STATE GENERATE 4 TRACE SCAN l 5 WAVE MODE i Document GP UM PMD 1000 21 Page 29 of 122 Use the up and down arrow keys to move between menu options and the ENTER key the center key in the arrow keypad to select the desired option l SCRAMBLING This option enables the random or continuous triangle wave based scrambling functions of the PMDPro Selecting this option brings up the following screen A RANDOM SCRAMBLE B TRIANGLE SCRAMBLE Selecting RANDOM SCRAMBLE brings up the following screen RAN SCRM FR 0500Hz 2 73ps 1 4ps2 Selecting TRIANGLE SCRAMBLE brings up the following screen TRISCRM FR 100 00Hz 10 71ps 0 0 ps2 For either scrambling mode the top line shows the selected scrambling mode and frequency and the bottom line shows the current DGD and SOPMD Select the desired scrambling frequency Use the left and right arrows to move between digits and the up and down arrows to increment the values The scrambling frequency range is 1 6000 Hz for random scrambling and 0 01 500 Hz for triangle scrambling When the desired frequency is set press the ENTER button The PMDPro will begin scrambling The s
23. dgd in ps and SOPMD value so in ps to memory location loc in memory Bank X Range for loc 0 to 99 Range for X A B C D or E Example SAV CON MBA 2 5 90 205 0 Save DGD 5 90ps SOPMD 205 0ps to memory location 2 in Bank A REC MBX loc Recall and generate PMD values stored at memory location Joc in memory bank X If value stored is a continuous setting dgd sopmd the PMDPro will recall the stored values calculate the closest available match and generate the calculated values Range for loc 0 to 99 Range for X A B C D or E Ex REC MBC 32 Recall PMD stored at location 32 in Memory Bank C and set PMDPro to that value REC MBxX loc Query PMD values continuous or ID discrete stored at memory location loc in memory bank X Will not set PMDPro to recalled PMD value Range for loc 0 to 99 Range for X A B C D or E Continuous CON dgd sopmd Example CON 25 5 180 0 Discrete DIS id Example DIS 19 Document GP UM PMD 1000 21 Page 99 of 122 SAV PMC loc Store the most recent PMDC Search result to PMDC memory location loc Range for loc 0 to 99 Ex SAV PMC 14 REC PMC loc SETUP MODE CHA Recall the stored PMDC Search result from PMDC memory location loc and set PMDPro to the recalled setting Range for loc 0 to 99 Query ITU grid channel number setting See Appendix A for wavelength frequency correspondence L
24. is a 3D graph of DOP vs SOPMD and DGD It can be rotated or zoomed for viewing from different perspectives To rotate a 3D graph drag it with the mouse To zoom in or out hover the mouse over it and scroll up or down After the scan is finished the data can be saved to a file by clicking SAVE DATA Data is saved as a text file with 3 columns DGD SOPMD and DOP Document GP UM PMD 1000 21 Page 83 of 122 Scan DGD SOPMD value in table This function scans through a set of user defined DGD SOPMD pairs PMD 1000 182 ps Polarization Optimized PMD Source PMD Control Program Ver 2 0 PMD Measurement DGD Measurement Instantaneous DGD ps Instantaneous SOPMD ps7 Output DOP Bq Sean interval 5 Wavelength nm SOPMD ps2 o 0A 100 2 Joa 1550 12 i 060 DOP DOP OGD SOPMO Monitor ii ii Manual it Advanced PMDE PMD Measurement Long Term PMD Monitor Setup eS ee O 5 10 15 2 25 30 35 40 45 SO SS 6 Store Recall RE Eble with Max DOP Max DOP ps Max DOP ips 2 1008 25 28 790 Thi PMD Calculation Exit F9 Con ndi Press S J oT C ET Enter the PMD values to be scanned in the table on the left of the screen Each row designates one DGD SOPMD pair The DGD value in ps should be entered in the first column and the SOPMD value in ps in the second column As in the other scan functions the dwell time per point Scan Interval in s should be set
25. match to the requested value At this point the PMDPro has not yet changed the output DGD or SOPMD values it has only displayed the results of the match calculation If the user is satisfied with the matched values he can press the ENTER key again to execute the setting and change the output DGD and SOPMD to the calculated values The LCD will display Document GP UM PMD 1000 21 Page 102 of 122 DGD 31 04 E 31 10 SOPMD _ 530 0 E 530 0 where the E indicates that the calculated values have been enabled From either the calculation or execution screens the left arrow key can be used to return to the setting mode the C or E will change back to the lt symbol and change the requested DGD and SOPMD values 3 Press the SOP button to bring up the polarization control options Select the SCRAMBLING option Select TRIANGLE SCRAMBLE The following screen will come up The bottom line displays the current DGD and SOPMD value setting TRI SCRM FR 100 0Hz 10 71 ps 0 0 ps2 Select the desired scrambling frequency using the arrow buttons The frequency range is 0 01 500 Hz After the frequency is set press the ENTER button to begin scrambling The cursor will move to the bottom right of the screen while scrambling is enabled Pressing the left arrow key will disable the scrambling and move the cursor back to frequency selection Control Program The setup process using the control program is similar to that us
26. optimizes the input SOP to find the DGD value that best compensates the PMD of the system under test When this option is selected the PMDPro immediately begins searching DGD Searching PLEASE WAIT When the optimum DGD value is found the screen displays DOP I 32 1 O 96 5 DGD 17 85ps ID 50 The bottom line shows the DGD value and corresponding index number that provide the best compensation for the system PMD This DGD value can also be considered a measurement of the amount of DGD in the system The top line displays the measured DOP at the input I and output O polarimeters The output DOP indicates how well the system PMD is compensated The polarization controller continues to actively optimize SOP as long as the PMDPro is in this mode PMD OPTIMIZED COMP This function scans through all 6561 PMD states in the lookup table including states with zero SOPMD wavelength independent SOPMD and wavelength dependent SOPMD and optimizes the input SOP to find the PMD value that best compensates the PMD of the system under test When this option is selected the PMDPro immediately begins searching PMD Searching PLEASE WAIT When the optimum value is found the screen displays Document GP UM PMD 1000 21 Page 40 of 122 DOP I 33 9 O 87 2 41 95ps 22 4ps2 The bottom line shows the DGD and SOPMD values that provide the best compensation for the system PMD This PMD value can also be considered a measure
27. rotator to achieve independent DGD and SOPMD control allowing it to uniformly cover the PMD space as shown in Figure 35 Note that the SOPMD values generated using this method are wavelength independent so there are no FSR issues 90ps PMDPro 180ps PMDPro 2500 10000 lt 2000 lt 8000 2 oo S 1500 6000 S QO 1000 A 4000 a 2 500 2000 0 0 4 0 20 40 60 80 100 DGD ps DGD ps Figure 35 DGD and wavelength independent SOPMD range A 90 ps PMDPro B 180 ps PMDPro Document GP UM PMD 1000 21 Page 113 of 122 5 6 Advantages and applications of the polarization optimized PMD source The polarization optimized PMD source constructed with digital ternary polarization rotators offers the following attractive features for PMD related testing 1 2 3 4 5 High precision high repeatability PMD generation resulting from the highly repeatable rotation angles of each ternary rotator In its discrete digital control mode the PMD source can generate a total of 6561 different PMD states of which 256 are DGD only 1024 have DGD and wavelength independent SOPMD and the rest are wavelength dependent PMD In its quasi continuous operation mode it can generate states with independently controllable DGD and wavelength independent SOPMD values Users can select individual PMD states or scan sequences of PMD states at user defined time intervals High PMD
28. the user to set the static IP configuration information Input the information into the corresponding boxes and click the SET button As each value is written its indicator turns green When all of the information is successfully stored the Set OK indicator will turn green Document GP UM PMD 1000 21 Page 54 of 122 GP_SET_ETHERNET vi gt 2 6 Ranaral Dhatanire D GP ETHERNET SETUP Sitti I E mvEewviivns Serial Port Baud Rate Port Configuration coma 28800 Note RS 232 baud rate must be 28800bps GET IP CONFIG MODE SETTING STATIC IP SETTING Set IP Address 192 168 2 106 Input all of the parameters then click S Set Net Mask 255 255 255 0 Set Gateway 2 168 2 1 Set Nameserver 192 168 2 2 Set OK Set Port 23 et to apply it STOP Program Static IP setup screen Notes on configuration The net mask and gateway should be the same as those for the control computer see example below The first 3 groups of numbers in the IP address should be the same as those for the control computer 192 168 2 for example The last number can be any available number but cannot be the same as the IP address of the control computer If the last number of the computer s subnet mask is n the available IP address range is n 1 to 254 For example if n 0 then the available IP addresses are 1 to 254 Then if the computer s IP address is 1
29. value or Contin for a continuous mode PMD value The ENTER key selects the displayed location Document GP UM PMD 1000 21 Page 28 of 122 e 4 2 4 SOP INTERVAL This option sets the dwell time per point in ms Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit Note that a particular memory bank can store discrete mode PMD states continuous mode PMD states or a mixture of the two If the memory bank contains only discrete mode values or only continuous mode values the dwell time range is 1 to 60 000 ms If the memory bank contains both discrete and continuous mode PMD values the minimum dwell time is 100 ms The ENTER key selects the displayed value CYCLES This option sets the number of times to run the scan The cycle range is 1 9999 Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit The ENTER key sets the number of cycles to the displayed value Pressing the SOP key accesses the PMDPro s deterministic polarization control and scrambling functions including generation and stabilization of a single SOP specified via Stokes parameters continuous or random scrambling or generation of specified If the PMDPro s PMD generator is set for a static PMD value i e not scanning that PMD setting will be unchanged during any polarization control accessed through the SOP For deterministic polarization
30. will auto adjust to satisfy the normalization condition However if the user sets a condition that does not satisfy the normalization condition the program will display an error message Document GP UM PMD 1000 21 Page 61 of 122 51 51 52 52 should be less than 1 6 STATE GENERATOR 45 45 90 RHC LHC This function generates and maintains any of the Poincar sphere pole points 0 45 45 or 90 linear states or right hand or left hand circular states Select the desired state from the pull down menu and click Set TRACE SCAN This function traces out a great circle on the Poincar sphere about the selected axis Po 45 45 90 3 0 SCAN ALL Select the desired axis from the pull down menu and set the dwell time per point Speed in ms and step size between points in degrees Then click Start to begin generating the trace SCAN ALL traces out one circle about each axis in turn Document GP UM PMD 1000 21 Page 62 of 122 PMDC This panel controls the PMD 1000 s PMD compensation functions using discrete PMD generation mode In all of these cases the PMD 1000 uses its polarization controller and polarimeters to maximize the output DOP but the DGD or PMD value used for compensation differs depending on the particular function selection MD 1000 182 ps Polarization Optimized PMD Source PMD Control Program Ver 2 0 Ist ORDER PMD COMPENSATION Search for
31. will then make 2 round trips along the second trace red in the example above starting and ending at point 30 34 0 and so on If the scan mode is set to continuous the PMDPro traverses the trace at a constant rate of change of DGD Set the scan rate in ps s using the up and down arrows or by typing in the box The range for scan rate is 0 1 to 100 ps s If the scan mode is set to step the scan speed is determined by the step size and dwell time The step size is the DGD difference in ps between consecutive points and the dwell time is the time in seconds that the PMDPro stays on each point The step size range is 0 1 to 64 ps and the dwell time range is 0 001 to 9 999s Once the trace list and scan operation parameters are configured click the Start button to begin The monitor block on the right of the screen shows the progress of the scan The cursor will move along the traces as the PMD changes The indicator boxes above the graph monitor the progress of an individual trace segment As the trace is generated they show the instantaneous DGD and SOPMD values and the number of cycles completed for the current trace segment The indicator boxes under the graph provide the definition information for the current trace segment the DGD SOPMD values for the start and end points and the trace number index number indicating its order in the list Local PMD Scan This set of functions allows the user to scan throu
32. 0 1533 47 c80 195550 1533 07 C81 195600 1532 68 C82 195650 1532 29 C83 195700 1531 90 C84 195750 1531 51 C85 195800 1531 12 C86 195850 1530 72 C87 195900 1530 33 Document GP UM PMD 1000 21 Page 119 of 122 L BAND CHANNEL FREQUENCY GHz WAVELENGTH nm L1 185100 1619 62 L2 185150 1619 19 L3 185200 1618 75 L4 185250 1618 31 L5 185300 1617 88 L6 185350 1617 44 L7 185400 1617 00 L8 185450 1616 57 L9 185500 1616 13 L10 185550 1615 70 L11 185600 1615 26 L12 185650 1614 83 L13 185700 1614 39 L14 185750 1613 96 L15 185800 1613 52 L16 185850 1613 09 L17 185900 1612 65 L18 185950 1612 22 L19 186000 1611 79 L20 186050 1611 35 L21 186100 1610 92 L22 186150 1610 49 L23 186200 1610 06 L24 186250 1609 62 L25 186300 1609 19 L26 186350 1608 76 L27 186400 1608 33 L28 186450 1607 90 L29 186500 1607 47 L30 186550 1607 04 L31 186600 1606 60 L32 186650 1606 17 L33 186700 1605 74 L34 186750 1605 31 L35 186800 1604 88 L36 186850 1604 46 L37 186900 1604 03 L38 186950 1603 60 L39 187000 1603 17 L40 187050 1602 74 L41 187100 1602 31 L42 187150 1601 88 L43 187200 1601 46 Document GP UM PMD 1000 21 Page 120 of 122
33. 190500 1573 71 L110 190550 1573 30 L111 190600 1572 89 L112 190650 1572 48 L113 190700 1572 06 L114 190750 1571 65 L115 190800 1571 24 L116 190850 1570 83 L117 190900 1570 42 L118 190950 1570 01 L119 191000 1569 59 L120 191050 1569 18 L121 191100 1568 77 L122 191150 1568 36 L123 191200 1567 95 L124 191250 1567 54 L125 191300 1567 13 L126 191350 1566 72 L127 191400 1566 31 L128 191450 1565 90 L129 191500 1565 50 L130 191550 1565 09 Document GP UM PMD 1000 21 Page 122 of 122
34. 192300 1558 98 C16 192350 1558 58 C17 192400 1558 17 C18 192450 1557 77 C19 192500 1557 36 C20 192550 1556 96 C21 192600 1556 55 C22 192650 1556 15 C23 192700 1555 75 C24 192750 1555 34 C25 192800 1554 94 C26 192850 1554 54 C27 192900 1554 13 C28 192950 1553 73 C29 193000 1553 33 C30 193050 1552 93 C31 193100 1552 52 C32 193150 1552 12 C33 193200 1551 72 C34 193250 1551 32 C35 193300 1550 92 C36 193350 1550 52 C37 193400 C38 193450 1549 72 C39 193500 1549 32 Document GP UM PMD 1000 21 Page 118 of 122 C40 193550 1548 91 C41 193600 1548 51 C42 193650 1548 11 C43 193700 1547 72 C44 193750 1547 32 C45 193800 1546 92 C46 193850 1546 52 C47 193900 1546 12 C48 193950 1545 72 C49 194000 1545 32 C50 194050 1544 92 C51 194100 1544 53 C52 194150 1544 13 C53 194200 1543 73 C54 194250 1543 33 C55 194300 1542 94 C56 194350 1542 54 C57 194400 1542 14 C58 194450 1541 75 C59 194500 1541 35 C60 194550 1540 95 C61 194600 1540 56 C62 194650 1540 16 C63 194700 1539 77 C64 194750 1539 37 C65 194800 1538 98 C66 194850 1538 58 C67 194900 1538 19 C68 194950 1537 79 C69 195000 1537 40 C70 195050 1537 00 C71 195100 1536 61 C72 195150 1536 22 C73 195200 1535 82 C74 195250 1535 43 C75 195300 1535 04 C76 195350 1534 64 C77 195400 1534 25 C78 195450 1533 86 C79 19550
35. 2 single DGD value with maximum DOP value PMDE Start Optimized 0 36 ps DGD WSOP soP 9 INPUT DOP i OUTPUT DOP i 1st amp 2nd ORDER PMD COMPENSATION Search for a single PMD valve with maximum DOP value Optimized SOPMD o INPUT DOP 100 te OUTPUT DOP Monitor Optimized 5 ane DGD 0 Manual AESA Fee SELECTED Ist ORDER PMD COMPENSATION PMD Measurement a Start PMD ID v DGD Value Long Term PMD Monitor INPUT DOP a OUTPUT DOP Setup SELECTED Ist amp Ind ORDER PMD COMPENSATION Store Recall start PMD D 0 ps SOPMD PMD Calculation Exit F9 INPUT DOP OUTPUT DOP Co ASRL4 INSTR pereniand Press Send to transmi mand to PMID 1000 Response 1 ORDER PMD COMPENSATION Click the Start button in this box to begin The PMD 1000 scans through all DGD states with SOPMD 0 in the lookup table and optimizes the SOP at each state to find the DGD value that best compensates the PMD at the input to the instrument It displays the resulting DGD value as well as the input and output DOP values 1 amp 2 ORDER PMD COMPENSATION Click the Start button in this box to begin The PMD 1000 scans through all DGD SOPMD pairs in the lookup table and optimizes the SOP at each point to find the DGD SOPMD pair that best compensates the PMD at the input to the instrument It displays the resulting DGD and SOPMD values as well as the input and output DOP values SELECTED 1 ORDER PMD COMPENSAT
36. 7 the user can set the IP address for the PMDPro to any number in the range 1 254 except 17 Notes e To connect the instrument directly to a PC use a PC to PC cable To connect the instrument to a LAN use a standard network cable e For Ethernet control the serial port is only used during Ethernet setup via the GP_SET ETHERNET program e The remote control command format is the same for all communication protocols RS 232 USB Ethernet GPIB 4 3 7 Control Program Interface Connect the PMDPro to the control computer using the desired remote control interface RS 232 USB Ethernet or GPIB and power on the instrument When the control program is first started it will ask if the control interface is Ethernet Document GP UM PMD 1000 21 Page 55 of 122 ib Do you want to connect with PMDPro with Ethernet Yes If the yes button is clicked the user will be prompted to enter an IP address Prompt User for Input Enter the IP Address IP Address Enter the instrument s IP address and click OK The user can set the PMDPro for static or dynamic IP addressing and query the IP address from the menu options accessible by pressing the SETUP button on the front panel If the no button is clicked the program will auto sense the control interface USB RS 232 or GPIB and the port being used Always close the control program before turning off the instrument Monitor Sc
37. 97 of 122 SOP CHx MOD Query Channel x waveform type setting x 1 to 4 Waveforms SIN sine SQU square TRI triangle Default Sine all channels Possible Responses SIN SQU TRI SOP CHx AMP amp Set Channel x Amplitude to value amp Volts E00 if successful See Table 2 for x to4 other error code definitions Range for amp 0 to 150 0 SOP CHx FRQ frq Set Channel x Frequency to value frq Hz E00 if successful See Table 2 for x 1 to 4 Range for frq 0 to 120 Hz other error code definitions SOP CHx SIN Set Channel x to Sine Wave Mode x l to4 EOO if successful See Table 2 for other error code definitions SOP CHx SQU Set Channel x to Square Wave Mode x 1 to 4 EOO if successful See Table 2 for other error code definitions SOP CHx TRI Set Channel x to Triangle Wave Mode E00 if successful See Table 2 for x to 4 other error code definitions WSOP MODE WSP SOP Enable worst case input SOP alignment based E00 if successful See Table 2 for on equal power split between DGD axes other error code definitions Valid in discrete PMD mode only for PMD ID in range 0 to 255 WSP DOP Enable worst case input SOP alignment based E00 if successful See Table 2 for on minimum output DOP other error code definitions Valid for any PMD setting PMD setting used is the most recently set discrete or continuous PMD value WSP DI
38. Band Range L001 to L130 C Band Range C001 to C087 E00 if successful E12 if location is empty or contains invalid data See Table 2 for other error code definitions Example L112 or C012 CHL nnn Set L BAND CHC nnn Set C BAND Set wavelength frequency channel setting using ITU grid index see Appendix A L Band Range L001 to L130 C Band Range C001 to C087 EOO if successful See Table 2 for other error code definitions Available range depends on PMDPro configuration ordered ADR adr Set GPIB address E00 if successful See Table 2 for Range to 30 other error code definitions Example ADR 5 ADR Query GPIB address Return 30 Set Ethernet Mode and Note This set of commands must be sent Query IP Address from RS 232 only TDHCP Set instrument to dynamic IP mode OK 6STIP Set instrument to static IP mode OK 8IP Request IP address IP Address will be returned E E E E E Note Returns either dynamic or static IP address depending on which mode is active Table 2 Error Code Definitions E00 No error Correctly formatted command received Undefined Command Parameter outside the allowed range Input power too high Input power too low Option Not Supported when in Continuous Mode ID out of range E12 Memory data location is empty or stored data is invalid Option Not Supported when in Discrete Mode E5 Invalid Stokes pa
39. DPro and Ex If the most recently set state on a 90 2 maximum SOPMD available with the DGD ps PMDPro is 30 37 100 0 this query corresponding to the most recently set continuous will return 9 1 3 xxxx x where xxxx x DGD SOPMD pair is the maximum SOPMD available with DGD 30 37 PMD CON pmd sopmd Continuous mode PMD control E00 if successful Calculates closest available DGD and SOPMD E06 if one of the requested values is values to the ones requested and generates the out of range calculated values See Table 2 for other error code pmd Requested DGD in ps definitions Range 0 91 04 for 90 ps unit 0 36 182 4 for 180 ps unit sopmd Requested SOPMD in ps Range 0 2079 97 for 90 ps unit 0 8319 9 for 180 ps unit PME Query PMD generator operational mode Response CON Continuous PMD trace scan STP Step PMD trace scan ANA Continuous Mode single state setup DGD DGD lookup table scan PMD PMD lookup table scan DSC Discrete Mode single state setup Document GP UM PMD 1000 21 Page 93 of 122 PME SET PMD idn Discrete mode PMD control Set DGD SOPMD to values corresponding to ID EOO if successful See Table 2 for other error code definitions LCD idn display will update Range 0 to 6560 PMDE MODE PMD Scans e a a PME SCN DGD min max Discrete mode DGD scan E00 if successful Scan DGD values in lookup table from start ID value min to end ID value
40. E SCN MBA mn mx PME SCN MBB mn mx PME SCN MBC mn mx PME SCN MBD mn mx PME SCN MBE mn mx Scan PMD values stored in a memory bank From memory location mn to mx Range for mn mx 0 to 99 mn lt mx MBX Memory Bank X X A B C DorE EOO if successful See Table 2 for other error code definitions PME SCN TYP bnk mn mx Query whether Location Range mn to mx of Memory Bank bnk contains only one type discrete lookup table or continuous of PMD values or a mixture of types MIX Range contains both discrete and continuous PMD values UNI Range contains only discrete or only continuous PMD values PME SCN DIS Stop Scan Discrete mode DGD PMD scan or Memory bank scan EOO if successful See Table 2 for other error code definitions MAXWELLIAN MODE STATISTICAL DGD EMULATION PME MXW ENA Start 1 order PMD Maxwellian statistical emulation E00 if successful See Table 2 for other error code definitions PME MXW DIS Stop Maxwellian statistical emulation E00 if successful See Table 2 for other error code definitions PME MXW AVE dgd Set Maxwellian average DGD value in ps Range 0 to Max DGD 2 EOO if successful See Table 2 for other error code definitions PME MXW AVE Query average DGD value setting 20 Value given in ps PME MXW DGD Query current DGD ID during scan 23 PME MXW SMP sample Set number of samples for
41. Figure 36 because the optimized PMD value for compensation should be close to the PMD value of the fiber link Therefore the PMD value of a fiber link can be determined by simply inserting a polarization optimized PMD source in the light path and enabling the PMD compensation function The optimized PMD value identified by the instrument is then the PMD value of the link It may also be necessary to characterize the PMD of a particular channel route in an in service ROADM network to determine its feasibility for 40G operation before installing 40G transmitters and receivers In such a situation an ASE source can be placed at the transmitter end and a polarization optimized PMD source at the receiver end to perform PMD compensation The optimized PMD value identified by the PMD source is then the PMD value of the fiber route With this information it is possible to decide whether the route is suitable for 40G transmission and whether Document GP UM PMD 1000 21 Page 114 of 122 a PMD compensator is required An EDFA may be used before the PMD source to boost the signal level Polarization optimized PMD source Link with PMD Figure 36 Polarization optimized PMD source in an in service WDM link for the determination of its PMD and diagnosis of performance issues 6 7 8 System impairment diagnosis It can be difficult to identify the cause of performance problems in a fiber link Signal degradation can be caused by PMD chromati
42. GD 19 90 SO _ 300 0 Again the stored DGD and SOPMD values are displayed in the bottom row 2 PMDC RESULT This option allows the user to recall previously stored PMD compensation data and apply the stored DGD or PMD value to a new selected DGD or PMD compensation run When the PMDC RESULT option is selected from the RECALL options menu the LCD displays the following screen Document GP UM PMD 1000 21 Page 45 of 122 DOP I 37 2 O 98 4 R ID 18 MEM Lo 0 This is the PMDC data stored at memory location MEM Lo 18 The top line of the screen shows the stored DOP measured by the input 1 and output O polarimeters and the bottom line shows the PMD index number ID used for the PMD compensation To look at data stored in a different memory location use the arrow keys to select the desired memory location index range 0 99 The DOP values and PMD index will change in real time to the values stored at the selected memory location Pressing ENTER from a recalled PMDC result screen will begin a new selected DGD or PMD compensation run using the PMD or DGD value from the recalled data set 4 3 Remote Control Operation General Photonics provides a control program for the PMDPro which allows access to several advanced functions as well as the basic functions accessible from the front panel The following sections describe the system requirements setup and control program interface 4 3 1 System Requirements e Operating system
43. ION Select the desired DGD index number PMD ID and click the Start button The PMD 1000 optimizes the SOP to maximize the output DOP using the selected DGD value It displays the selected DGD value as well as the input and output DOP values SELECTED 1 amp 2 ORDER PMD COMPENSATION Select the desired PMD index number PMD ID and click the Start button The PMD 1000 optimizes the SOP to maximize the output DOP using the selected DGD SOPMD values It displays the selected DGD and SOPMD values as well as the input and output DOP values Document GP UM PMD 1000 21 Page 63 of 122 MONITOR This screen was described at the beginning of the control program description It can be used to monitor the status of the light signal including the output optical power the current output PMD setting and control mode of the PMD generator and the SOP DOP values at the input and output polarimeters 182 ps Polarization Optimized PMD Source PMD Control Program Ver 2 0 OUTPUT POWER Power PMDC DGD SOPMD Display the current DGD SOPMD senting Monitor DGD 179 98 G Manual Advanced PMDE PMD Measurement Long Term PMD Monitor oar OUTPUT Store Recall PMD Calculation n s 0 454 Exit F9 mmand to PMID 1000 p m INSTR p monon E m Paane a Document GP UM PMD 1000 21 Page 64 of 122 MANUAL The PMD 1000 includes a 6 channel piezo driven fiber squeezer polarization control
44. L44 187250 1601 03 L45 187300 1600 60 L46 187350 1600 17 L47 187400 1599 75 L48 187450 1599 32 L49 187500 1598 89 L50 187550 1598 47 L51 187600 1598 04 L52 187650 1597 62 L53 187700 1597 19 L54 187750 1596 76 L55 187800 1596 34 L56 187850 1595 91 L57 187900 1595 49 L58 187950 1595 06 L59 188000 1594 64 L60 188050 1594 22 L61 188100 1593 79 L62 188150 1593 37 L63 188200 1592 95 L64 188250 1592 52 L65 188300 1592 10 L66 188350 1591 68 L67 188400 1591 26 L68 188450 1590 83 L69 188500 1590 41 L70 188550 1589 99 L71 188600 1589 57 L72 188650 1589 15 L73 188700 1588 73 L74 188750 1588 30 L75 188800 1587 88 L76 188850 1587 46 L77 188900 1587 04 L78 188950 1586 62 L79 189000 1586 20 L80 189050 1585 78 L81 189100 1585 36 L82 189150 1584 95 L83 189200 1584 53 L84 189250 1584 11 L85 189300 1583 69 L86 189350 1583 27 L87 189400 1582 85 L88 189450 1582 44 L89 189500 1582 02 L90 189550 1581 60 L91 189600 1581 18 Document GP UM PMD 1000 21 Page 121 of 122 L92 189650 1580 77 L93 189700 1580 35 L94 189750 1579 93 L95 189800 1579 52 L96 189850 1579 10 L97 189900 1578 69 L98 189950 1578 27 L99 190000 1577 86 L100 190050 1577 44 L101 190100 1577 03 L102 190150 1576 61 L103 190200 1576 20 L104 190250 1575 78 L105 190300 1575 37 L106 190350 1574 95 L107 190400 1574 54 L108 190450 1574 13 L109
45. Local PMD Scan Instantaneous DGD ps Instantaneous SOPMD ps2 Output DOP Scan Interval 5 PMDC 5372 7 14 Monitor Manual Advanced PMDE sszsg PMD Measurement Long Term PMD Monitor o r p 2 p 0 g J Setup 2000 2500 3X00 3500 4000 4500 5000 5500 If SOPMO i Store Recall PMD Calculation Exit F9 i Selection parameters Fixed DGD fixed DGD value in ps Start SOPMD SOPMD start value in ps Stop SOPMD SOPMD end value in ps SOPMD step step size in ps Scan Interval on top of graph dwell time per point in s Minimum value 0 4 s Document GP UM PMD 1000 21 Page 77 of 122 When the scan parameters are set click Start to start the scan As each point is generated the DGD SOPMD and output DOP are displayed above the graph and the output DOP vs SOPMD is plotted in the graph on the left After the scan is finished the data can be saved to a file by clicking SAVE DATA Data is saved as a text file with 3 columns DGD SOPMD and DOP Scan DGD and SOPMD This function performs a scan of a 2 D grid in PMD space The user defines the grid by specifying the DGD and SOPMD limit points and step sizes PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 Continuous PMD Polarization Control Scan Stored PMD PMD Emulation PMD Scan PMD TraceScan Local PMD Scan Start OGD Instantaneo
46. MD 1000 21 Page 60 of 122 SOP The SOP operation screen includes the PMD 1000 s polarization control and scrambling functions PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 SCRAMBLING Random r l 000 6000 MZ 1 a y Monitor Manual SET SOP O Sig 1 000 2 7 Th f S1 S2 and 3 must be Advanced PMDE SEER Fan must be equal to PMD Meas ent 6 STATE GENERATOR Long Term PMD Monitor Setup TRACE SCAN Store Recall PMD Calculation Exit F9 ASRL4 INSTR Command Press Send to transmi mand to PMD 1000 Response eae aa E SCRAMBLING The PMD 1000 can perform either random scrambling in which it generates random discontinuous points on the Poincar sphere or continuous scrambling in which it uses an algorithm based on a set of triangle waves to generate a continuous trace on the Poincar sphere Select the frequency for the desired scrambling mode random or triangle and click the corresponding Start button to begin scrambling Frequency ranges Random scrambling 1 6000 Hz Triangle scrambling 0 01 500 Hz SET SOP Use this function to set and maintain a particular SOP Set the Stokes parameters of the desired state making sure that they fulfill the condition S S S 1 and then click the Set button to generate and maintain that state In most cases as the user adjusts one Stokes parameter the others
47. MD Contr SOPHO 137 39 3 19 DGO 181 390 137 826 10 737 lt Monitor 161 71 1 o 161 70 210 0 161 390 137 39 HOOSCOCOSOSOHOCOM p mi p mt MooococoooOmOCcOouKN Bea Manual Advanced PMDE PMD Measurement Long Term PMD Monitor Setup Store Recall PMD Calculation Exit F9 Import Data previously exported to a text file can be imported by clicking the IMPORT button The program will prompt for a file name and location and the imported data will be displayed in the table on screen It can then be stored to a memory bank by selecting a memory bank A E and clicking the STORE button Clear The selected memory bank can be cleared by clicking the CLEAR button The program will prompt the user to confirm Document GP UM PMD 1000 21 Page 90 of 122 Clear All the Value Cancel Click OK to delete the stored data PMDC Memory Bank Store Recall The PMDPro can also perform individual DGD measurements and save the results to memory Up to 100 results can be stored PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 PMD Memory Bank Store Recall PMDC Memory Bank Store Recall PMD Measure amp Store Optimized PMD Value in the Memory se me ENAT PMDC a s Ds a 2 4 3034 00 Monitor a as 000 DGD E __ Manual 21 06 BE 1892 000 102 719 000 2 a 000 25 5 182 43 0 00 A
48. Making Light Work Lighter General Photonics PMD 1000 PMDPro Polarization Optimized PMD Source Operation Manual Version 2 1 Oe Z POLARIZATION OPTIMIZED PMO SOURCE A SAAR Silane comrenasrion AND KOLEAAN TEST e INPUT November 16 2015 General Photonics Corp Ph 909 590 5473 5228 Edison Ave Fax 909 902 5536 Chino CA 91710 USA www generalphotonics com Document GP UM PMD 1000 21 Page 1 of 122 SAFETY CONSIDERATIONS The following safety precautions must be observed during operation service and repair of this instrument Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design manufacture and intended use of the instrument General Photonics Corp assumes no liability for customers failure to comply with these requirements e Before operation the user should inspect the instrument and review the manual carefully e The instrument s rear panel includes a chassis ground terminal for electrical safety e Make sure that the instrument is in a secured work environment in terms of temperature humidity electrical power hazard due to fire or shock etc for proper operation e Standard laser safety procedures should be followed during operation Document GP UM PMD 1000 21 Page 2 of 122 Table of Contents Section 1 Specifications os vcsc oe eee a as as SO ES 5 S cti n 2 Overview ae onia sence yada bua s
49. N A Selection parameters Start DGD DGD start value in ps Stop DGD DGD end value in ps DGD step step size in ps Fixed SOPMD fixed SOPMD value in ps Scan Interval on top of graph dwell time per point in s Minimum value 0 4 s Note that the SOPMD value setting may limit the DGD scan range When the scan parameters are set click Start to start the scan As each point is generated the DGD SOPMD and output DOP are displayed above the graph and the output DOP vs DGD is plotted in the graph on the left After the scan is finished the data can be saved to a file by clicking SAVE DATA The program will prompt for a filename and location Document GP UM PMD 1000 21 Page 76 of 122 Choose or Enter Path of File Save in E SN40 E SN40_ADC EG 2 SN40_sum_WL1530 00 My Recent E SN40_sum_WL1540 00 Documents SN40_sum_ VL1550 00 E SN40_sum_WL1560 00 E E sN40_sum_wWL 1565 00 6l SN40_temperature E SN40_VOA SN40_VOA processed leskto My Documents gs My Computer File name My Network Save as type Al Files Data is saved as a text file with 3 columns DGD SOPMD and DOP Scan SOPMD only This function scans through a user defined SOPMD range with a fixed DGD value Polarization Optimized PMD Source PMD Control Program Ver 2 0 Continuous PMD Polarization Control Scan Stored PMD PMD Emulation PMD Scan PMD Trace Scan
50. NG THE SOFTWARE AND OR CLICKING THE APPLICABLE BUTTON TO COMPLETE THE INSTALLATION PROCESS YOU CONSENT TO THE TERMS OF THIS AGREEMENT AND YOU AGREE TO BE BOUND BY THIS AGREEMENT IF YOU DO NOT WISH TO BECOME A PARTY TO THIS AGREEMENT AND BE BOUND BY ALL OF ITS TERMS AND CONDITIONS CLICK THE APPROPRIATE BUTTON TO CANCEL THE INSTALLATION PROCESS DO NOT INSTALL OR USE THE SOFTWARE AND RETURN THE SOFTWARE WITHIN THIRTY 30 DAYS OF RECEIPT OF THE SOFTWARE WITH ALL ACCOMPANYING WRITTFN MATFRIAI S Al ONG WITH THFIR CONTAINFRS TO THF PI ACF YOU ORTAINFD The software to which this National Instruments license applies is PMDPro Software I accept the above 2 License Agreement s Accept the license terms and click Next to proceed A summary page lists the files to be installed or changed Document GP UM PMD 1000 21 Page 47 of 122 rT LY PMDPro Software SSeS ee Start Installation Review the following summary before continuing Adding or Changing PMDPro Software Files e NIVISA 5 0 3 Run Time Support Click the Next button to begin installation Click the Back button to change the installation settings Save Fie lt lt Back _ _New gt gt J Canos Click Next to begin installation When all of the files are installed an installation complete screen will be displayed P LY PMDPro Software ESSE SSS ey Installation Complete The inst
51. OPMD values can also be increased as the BER of the system is measured and plotted as shown in Figure 31C The system outage probability can be calculated from the data obtained DGD tolerance DGD DGD Figure 31 A PMD tolerance test setup using a PMD source The computer selects PMD settings and collects BER readings B BER vs DGD curve The DGD tolerance of the system for a given BER threshold can be deduced using the curve C Map of BER vs DGD and SOPMD Each contour represents a BER value The PMD tolerance can be obtained from the contour plot PMD tolerance test results can be used by network operators to compare systems made by different vendors and to verify the PMD related specifications promised by the vendors They can also be used by system vendors to 1 determine which PMD mitigation approach is most suitable to adopt 2 to fine tune the PMD mitigation related parameters in the transceivers during system development and 3 to perform output quality control of the final system including transceivers for the PMD related specifications Document GP UM PMD 1000 21 Page 108 of 122 Importance of polarization optimization The PMD effect on a system is highly polarization dependent When the input state of polarization SOP is aligned or counter aligned with the principal state of polarization PSP of the fiber link or the PMD source the PMD has no effect on the signal and therefore no effect on system performance as sh
52. S Stop disable automatic worst case SOP E00 if successful See Table 2 for control other error code definitions MONITOR MODE MON PMD Query current or most recent PMD setting Return dgd sopmd Units DGD ps 2 order PMD ps Example 63 06 314 3 If not in PMD mode will return the last PMD value set MON POW Query output power Example 6 7 Default Units dBm MON DOP INP Query input DOP value in Ex 98 6 MON DOP OUT Query output DOP value in Ex 18 4 MON SOP INP Query input SOP value Returns the values of S1 S2 and S3 from the input polarimeter S1 0 60 S2 0 60 S3 0 53 MON SOP OUT MANUAL MODE CV1 x x CV2 x x CV3 x x CV4 x x CV5 x x CV6 x x Query output SOP value Returns the values of S1 S2 and S3 from the output polarimeter Set control voltages for single channels of the polarization controller Using these commands will put the PMDPro into manual mode if it is not in that mode already and set the voltage of the indicated channel to the specified value Range of x x 0 150 0 Volts S1 0 60 S2 0 60 S3 0 53 E00 if successful See Table 2 for other error code definitions Document GP UM PMD 1000 21 Page 98 of 122 CV1 Query the voltage of indicated channel Example 123 45 indicates that the CV2 Range 0 150 0 Volts control voltage is 123 45V for the CV3 queried channel CV4
53. SOPMD 0 Advanced PMDE Scan Imerval 100 ms 7 PMD Measurement Long Term PMD Monitor y SCAN PMD Setup Store Recall Scan Interval s 100 PMD Calculation Exit F9 y ASRL4 INSTR Command Press Send mand to PMD 1000 Response eae SS A SET PMD This function is used to select a particular DGD SOPMD state from the lookup table When the user selects a PMD index number ID the PMD 1000 generates the corresponding DGD SOPMD pair and displays the DGD and SOPMD values in the corresponding boxes Output values are updated in real time as the index number is changed DGD MAXWELLIAN DISTRIBUTION This is a first order PMD emulation function The PMD 1000 generates a Maxwellian statistical distribution of DGD values with the total number of samples Sample Num and average DGD in ps specified by the user The range for average DGD is 30 ps for a 90 ps PMDPro and 60 ps for a 180 ps PMDPro Cycle Num is the number of times the scan will be run Scan Interval is the dwell time per point in ms Only DGD states SOPMD 0 are used in the emulation SCAN DGD The PMD 1000 scans a series of DGD values with SOPMD 0 in a user defined range in order from lowest to highest Set the desired dwell time per point Scan Interval and number of times to run the scan Cycle by typing in the boxes or using the up and down arrows Set the start and end DGD values for the scan in ps by typing in the boxes and then clicking outs
54. Scan EOO if successful See Table 2 for other error code definitions PME SCN STE ENA Begin Step Trace Scan using current settings EOO if successful See Table 2 for other error code definitions PME SCN STE DIS Disable stop Step Trace Scan EOO if successful See Table 2 for other error code definitions PME SCN DWL dwell Set dwell time per point for step trace scan Range 1 to 9999 ms EOO if successful See Table 2 for other error code definitions PME SCN DWL Query the Dwell time in milliseconds 234 i e 234 ms PME SCN DIR UPD For continuous or step trace scan Set the Scan Start Direction to UP i e Scan from lower DGD limit to upper limit EOO if successful See Table 2 for other error code definitions PME SCN DIR DND For continuous or step trace scan Set the Scan Start Direction to DOWN i e Scan from upper DGD limit to lower limit EOO if successful See Table 2 for other error code definitions PME SCN DIR For continuous or step trace scan Query the scan direction Valid UPD UP Direction DND DOWN Direction END Scan done not scanning PME SCN MOD UNI For continuous or step trace scan Set the Scan MODE type to UNI Directional one way scan EOO if successful See Table 2 for other error code definitions PME SCN MOD BID For continuous or step trace scan Set the Scan MODE type to
55. Send to transmi mand to PMD 1000 Response M M sc a PMD SETTING First select the desired DGD SOPMD pair by setting the index number in the PMD ID box The corresponding DGD and SOPMD will be displayed in the adjacent boxes Click Set PMD to execute the setting EQUAL POWER SPLIT In this function the input polarimeter reading is used to control the polarization controller to align the input polarization state to obtain an equal power split between the polarization components aligned to the slow and fast axes of the PMD element This function can be used only with DGD only states SOPMD 0 These correspond to PMD index numbers 0 255 If a larger index number is selected this function will be disabled The Start Tracking button will be grayed out Click the Start Tracking button to begin the SOP search The DOP values measured by the input and output polarimeters are displayed in the corresponding boxes OPTIMIZE OUTPUT DOP TO MIN In this function the output polarimeter reading is used to control the polarization controller to tune the input polarization state to minimize the DOP of the signal after it passes through the PMD element This function can be used with any PMD value in the lookup table Click the Start Tracking button in this section of the screen to begin the search The DOP values measured by the input and output polarimeters are displayed in the corresponding boxes Document GP UM P
56. Way 192 168 1 1 NameServer 192 168 1 2 PORT 23 STOP Program IP Config query screen Static IP mode result Document GP UM PMD 1000 21 Page 52 of 122 Ej Gp_SET_ETHERNET vi Eile Edit Operate Tools Window Help alaie Panaral Dhatanire D GP ETHERNET SETUP Sitti I E HULUN J Serial Pot Baud Rate 28800 Note RS 232 baud rate must be 28800bps GET IP CONFIG MODE SETTING STATIC IP SETTING Port Configuration coma Click the button to get IPCONFIG IP Address 192 168 0 31 Get IP Config Net MASK 255 255 255 0 SUS taints a DYNAMIC STOP Program IP Config query screen Dynamic IP mode result The second tab MODE SETTING allows the user to switch the instrument between static and dynamic IP addressing modes Ej Gp_SeT_ETHERNET vi File Edit Qperate Tools Window Help alae Panaral Dhatanire p GP ETHERNET SETUP Sitti I tf HULUNIUJ Serial Pot Baud Rate Port Configuration com4 xl 28800 Note RS 232 baud rate must be 28800bps GET IP CONFIG MODE SETTING STATIC IP SETTING Select DYNAMIC Mode ok ETHERNET MODE Select STATIC Mode ok DYNAMIC STOP Program Ethernet mode selection screen dynamic Document GP UM PMD 1000 21 Page 53 of 122 E Gp_SeET_ETHERNET vi File Edit Operate Tools Window Hel gt a
57. age 22 of 122 b Rng This option selects the demi arc to be traced by specifying the DGD range Two DGD values are shown on this line The first DGD value listed is the endpoint on the DGD axis Use the left and right arrow keys to select the digit to be changed and the up and down arrow keys to increment the active digit The range for this value is 0 00 to 91 04 ps for a 90 ps PMDPro and 0 36 to 182 4 ps for a 180 ps PMDPro As the DGD axis endpoint is changed the other endpoint is adjusted accordingly Note that the second endpoint is not on the DGD axis while only its DGD value is displayed on this screen it does have a nonzero SOPMD Use the ENTER key to select the displayed DGD range c STEP DIRECTION This option determines the beginning point and direction of the scan UP scan begins at the lower DGD endpoint and proceeds in the direction of increasing DGD DN scan begins at the higher DGD endpoint and proceeds in the direction of decreasing DGD Use the up and down arrows to toggle the direction and the ENTER key to select the displayed setting d CYCLES This option sets the number of times to run the scan The cycle number range is 1 9999 Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit The ENTER key sets the number of cycles to the displayed value e MODE This option determines whether one cycle is defined as a single direction or round trip scan
58. aller has finished updating your system This completes the installation process Click Finish The computer will need to be restarted before the program can be used Document GP UM PMD 1000 21 Page 48 of 122 Drivers installed e LabVIEW Run Time Engine 2012 SP1 32 bit Operating system Windows 8 Windows 7 Windows Vista Windows XP SP3 32 bit Windows Server 2008 R2 64 bit Windows Server 2003 R2 32 bit e NI VISA Run Time Engine 5 3 Operating system Real Time OS Windows 7 64 bit Windows 7 32 bit Windows Vista 64 bit Windows Vista 32 bit Windows XP Windows XP Embedded Windows Server 2008 R2 64 bit Windows Server 2003 R2 32 bit e FTDI USB Driver requires additional steps see USB Setup section See Readme file for USB driver for version information 4 3 3 RS 232 Connection The RS 232 connector on the rear panel of the PMDPro is a DB9 male connector Use a straight connection RS 232 cable DB 9 female to female to connect the PMDPro to the RS 232 port of a computer To ensure proper communication use a serial cable with direct pin to pin connected wires see Figure 23 at both ends of the cable GND RXD TXD O gt o o DEO C C EE 98 7 Figure 23 RS 232 connector on rear panel of PMDPro RS 232 command notes 1 RS 232 port uses asynchronous framing 8 data bits no parity bit and 1 stop bit 2 RS 232 baud rate 28800 bps 4 3 4 USB Connection USB commu
59. an of the distribution can be taken to be the mean PMD of the system under test The program will continue recording data until the Stop button is clicked Support Functions This section includes the interface screens for setting operation parameters storing and recalling programmed PMD scan sequences and PMDC results and performing wavelength dependence simulations for PMD states in the discrete mode lookup table Setup This screen allows the user to set the basic operation parameters for the PMD 1000 PMD 1000 182 ps Polarization Optimized PMD Source PMD Control Program Ver 2 0 WSOP OPERATION WAVELENGTH PMDC Monitor C Band r Manual Advanced PMDE GPIB ADDRESS PMD Measurement Get GPIB Address Long Term PMD Monitor A Set GPIB Address Setup Store Recall PMD Calculation Exit F9 y Command Press Send to transmit command to PMD 1000 Response ee Setup parameters Operation Wavelength First select the wavelength band e g C or L band Then select the ITU grid channel number The indicator boxes will display the corresponding frequency in THz and wavelength in nm of the selected channel The wavelength setting updates in real time GPIB address Click Get to query the current GPIB address for the PMD 1000 To set a new address select the desired GPIB address in the Set GPIB address box then click Set Note This function can only be used if the curr
60. arameters This plot can be used to find a combination of average DGD and sample number that will yield a good distribution The SOPMD distribution plot shows the calculated distribution of SOPMD values that corresponds to the selected parameters If the dwell time per point scan interval is gt 1 s the program monitors the progress of the emulation As each point is generated the status block at the lower left of the screen shows the DGD and SOPMD sample number number of completed cycles and input and output DOP The generated PMD DGD and SOPMD distribution plots track the progress of the emulation When the emulation is complete the generated value plots will match the calculated value plots above them For dwell time values gt 1 s the WSOP function is also available Click the WSOP Enable button at the bottom left of the screen before starting the emulation to enable automatic polarization optimization for the worst case PMD effect at each DGD value For dwell time values lt 1 s the WSOP and scan monitoring functions are disabled The monitor plots are replaced by a progress bar Document GP UM PMD 1000 21 Page 72 of 122 PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 Continuous PMD Polarization Control Scan Stored PMD PMD Emulation PMD Scan PMO x 1l PMO Distribution SOPMO Distribution Average OGD Sample Jx 500 PMDC Step oso step gov
61. are with a constant user controllable DGD step size This is the step trace function The transient between consecutive points in a step trace follows the characteristic curve so that there are no discontinuous jumps during travel along a particular arc Document GP UM PMD 1000 21 Page 21 of 122 When the PMD Trace scan function is selected the following screen is displayed A CONTINUOUS TRACE B STEP TRACE A CONTINUOUS TRACE In continuous trace mode the PMDPro varies the PMD along the selected curve using the minimum DGD step size of 0 1 ps The user can select the DGD variation rate in ps s The setup screens for continuous trace mode are as follows a START con TRACE b Rng _0 00 64 4 ps c STEP DIRECTION UP d CYCLES _ _10 Count e MODE BI DIREC 7 f CON RATE __1 0 ps s Use the up and down arrows to move between scan setup options and the ENTER key to access the setup screen for the selected option a START This option starts the scan Use the other options to perform the scan setup then return to option a to begin the scan While the scan is running the screen displays CYC ___1 10 DIR 63 6 ps 2002 7ps2 CYC number of completed cycles total number of cycles to run DIR scan direction lt bidirectional unidirectional increasing DGD lt unidirectional decreasing DGD The bottom line displays the current DGD and SOPMD values Document GP UM PMD 1000 21 P
62. arrows to move between digits and the up and down arrows to increment the selected digit The minimum step size is 0 1 ps The maximum step size is determined by the range selected in option b The ENTER key selects the displayed value g DWELL time Set the dwell time at each point in ms Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit The dwell time range is 1 to 9999 ms The ENTER key selects the displayed value 5 DGD PMD Emulation This is the statistical PMD emulation function The PMDPro generates a Maxwellian distribution of DGD values with a user selected number of points and average DGD The SOPMD can either be zero first order PMD emulation only or can be a statistical distribution corresponding to the generated DGD When this option is selected the following screen is displayed Document GP UM PMD 1000 21 Page 24 of 122 A DGD ONLY EMULATION B PMD EMULATION Select the desired option and press ENTER A DGD ONLY EMULATION The setup screens for first order PMD emulation are as follows a START DGD Emula b AVERAGE DGD 10 0ps c SAMPLE NUM __ 1000 t d CYCLENUM 10 e INTERVAL 2000 ms ft Rng 1 ms to 60000 ms Use the up and down arrows to move between scan setup options and the ENTER key to access the setup screen for the selected option a START This option starts the emulation Use the other options to perform the setup t
63. ath 8 cAdata PMDPro data txt Advanced PMDE PMD M Long Term PMD Monitor Setup Store Recall PMD Calculation Exit F9 ASRLSINSTR Command Press Si mand to PMID 1000 Response rr OO ee The picture above shows the control program interface screen for the long term monitoring function Connect the DUT to the input of the PMDPro Setup parameters File Path Click the folder icon to select the file path to which the data should be saved Time Delay Time interval between measurements in seconds Frequency Frequency in THz of the signal to be measured As this value is updated the corresponding wavelength in nm will be displayed in the box immediately below the frequency box Once the setup is complete click Start to begin recording data The PMDPro will perform PMD measurements at the specified time intervals After each measurement is complete the PMDPro will record the following data to the file optical head temperature optimized DGD the DGD value for which the maximum output DOP was found input DOP output DOP and time stamp The input and output DOP vs time are plotted on the top right hand graph and the measured PMD vs time is plotted on the bottom right hand graph The histogram tracks the distribution of measured PMD values Document GP UM PMD 1000 21 Page 87 of 122 After a long enough period of measurement the histogram will typically follow a Maxwellian distribution The me
64. atic polarization controller and two polarimeters that continuously monitor the state of polarization SOP and degree of polarization DOP before and after the PMD generating elements The polarization controller can be operated using feedback from the input polarimeter to automatically align and maintain the input SOP such that there is an equal power split between polarization components aligned to the principal axes of the DGD element to obtain the worst case first order PMD effect Alternatively the controller can automatically adjust and maintain the input SOP using the feedback from the output polarimeter to either minimize or maximize the output DOP for each PMD setting Minimizing the output DOP enables testing of the worst case total PMD effect while maximizing the output DOP allows the PMDPro to act as a PMD compensator allowing the user to determine the optimum PMD values for PMD compensation The PMDPro can also perform PMD emulation by generating statistical distributions of first and second order PMD representing those of a real fiber link In addition the integrated polarization controller and polarimeters enable variable rate scrambling and deterministic polarization control functions including trace generation and polarization stabilization at any SOP Basic functions can be controlled either manually from the front panel keypad or remotely via RS 232 USB Ethernet or GPIB interfaces The control program also enables several ad
65. b TRACE Angle 0 c SPEED __100ms 1 d STEP 240 a START Selecting option a begins the trace scan Set up the scan parameters using the other options then return to option a to begin scanning The trace scan operation screen is shown below TRACE SCAN 0 0 00 ps 0 0 ps2 The top line shows the trace axis 0 in the example above The bottom line displays the current DGD and SOPMD The trace function will continue until the user selects another option b TRACE Angle This option allows the user to select the axis about which the great circle will be drawn The axis is a radius of the sphere oriented at a specified angle given in sphere coordinates from the S1 axis 0 The rotation axis is the S1 axis 45 The rotation axis is in the S1 S2 plane midway between the S1 and S2 axes 90 The rotation axis is the S2 axis 45 The rotation axis is in the S1 S2 plane midway between the S1 and S2 axes S3 0 The rotation axis is the S3 axis i e the polarization state stays linear with the inclination angle changing SCAN Traces one full circle about each axis in turn Document GP UM PMD 1000 21 Page 32 of 122 Cc S3 trace 45 trace 0 trace 90 trace 45 trace 0 trace 90 trace ji l 0 axis 77 y _ re rN OO axis PolaView AIV AARP jS Xi Toa Figure 9 0 and 90 axes and corresponding traces SPEED This opt
66. be the currently stored static IP address If no static IP address has been stored by the user the address displayed will be 0 0 0 0 4 GET STATIC IP Sets the PMDPro for static IP addressing and recalls the static IP address stored in memory GETTING STATIC IP Please Wait FIX 191 168 0 111 Static Mode Set i See section 4 3 6 for instructions on hardware setup for Ethernet connection 5 SET STATIC IP This menu option is a placeholder for a function that is planned for future versions of this instrument The static IP address and other parameters can be set using a LabView program see Ethernet setup section for details Document GP UM PMD 1000 21 Page 14 of 122 6 INITPMDE MEM BANK Clears stored values from the selected PMD sequence memory bank and restores it to its default configuration When this option is selected the following screen is displayed INIT PMDE MEM BANK A SELECT BNK TO INIT The cursor will blink on the memory bank index position A in the current example Use the left and right arrows to select the desired memory bank and press ENTER to clear it The instrument will ask the user to confirm the request to clear the memory bank INIT PMDE MEM BANK A INIT BANK A n y After the user confirms the data deletion the screen will display PLEASE WAIT When the reinitialization of the data bank is complete the machine will beep and the screen will return to the initialization
67. ble WSOP button This function is useful for PMD tolerance tests with single polarization signals The PMDPro monitors and displays the DOP values measured by the input and output polarimeters in the boxes above the Enable WSOP button Scan Stored PMD The PMD 1000 has 5 memory banks which can store up to 100 PMD settings each The user can thus store up to 5 sequences of PMD values and then use this function to scan through them PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 Continuous PMD Polarization Control Scan Stored PMD PMD Emulation PMD Scan Advanced PMDE SOPMO ps2 RIELE PMD Measurement Long Term PMD Monitor E Setup Store Recall Q x c r x 100 10 OGDips PMD Calculation Exit F9 Response ASRL4 INSTR i ee Select the desired memory bank A E and the beginning and ending locations within that bank to be used for the scan Set the desired dwell time per point Scan Interval If the selected memory bank contains only continuous PMD values or only discrete lookup table PMD values the minimum dwell time is 0 001 s If it contains a combination of continuous and discrete PMD values the minimum dwell time is 0 5 s If a dwell time lt 0 5 s is selected for a mixed set of continuous and discrete values the user will be Document GP UM PMD 1000 21 Page 67 of 122 prompted to either run the scan with a dwell t
68. c dispersion CD signal to noise ratio SNR issues or other problems Performing PMD compensation can help determine whether the problem is principally due to PMD If PMD compensation substantially solves the transmission problem it can be deduced that PMD is the principal cause of the problem If not it may be possible to rule out PMD With such a diagnosis it is possible to decide whether PMD compensation is required for the fiber link PMD emulation The PMD generator can generate statistical PMD distributions to emulate PMD variations in fiber systems Polarization control functions Using its built in polarization controller and polarimeters this instrument can perform all polarization control functions including deterministic SOP generation polarization scrambling and polarization trace generation It can therefore be used as a general purpose polarization synthesizer controller for all polarization control needs Polarization optimization is used in the following three functions 1 2 3 DGD tolerance test Optimize input SOP using the SOP information from the first polarimeter as feedback to obtain the worst case signal degradation caused by DGD PMD tolerance test Optimize input SOP to minimize the DOP detected by the second polarimeter to obtain the worst case signal degradation caused by both DGD and SOPMD PMD compensation Optimize input SOP by maximizing DOP detected by the second polarimeter to minimize signal
69. ce with user selectable DGD step size and dwell time at each point The transient between any two consecutive points on a trace still follows the trace however so either the continuous or step scan can be used for applications that require continuous PMD variation Scan Setting Scan Mode Step Direction Cyde Type Continuous zi EE Bi direction z DOWN The step direction pull down menu selects the direction of travel along the trace If UP is selected the PMDPro starts at the lower DGD limit point whether designated as start or end point and traverses the trace to the other limit point If DOWN is selected the PMDPro starts at the higher DGD limit point and traverses the trace to the lower DGD limit point Document GP UM PMD 1000 21 Page 74 of 122 Scan Setting Scan Mode Step Direction Uni Direction Bi direction Continuous lt i UP zi The cycle type pull down menu allows the user to select between a one way or round trip scan Cycle number designates how many times to generate each trace before going on to the next trace on the list In the example above the scan is set for continuous up bidirectional and 2 cycles with the first trace s limit points set at 0 36 ps 0 0 ps and 129 00 ps 8319 9 ps The PMDPro will make 2 round trips along the first trace yellow in the example above starting at point 0 36 0 going along the trace to point 129 00 8319 9 and back to point 0 36 0 It
70. creen display remains the same but the cursor will move to the bottom right corner of the screen During scrambling pressing the left arrow key will stop the scrambling and move the cursor to frequency selection so that the scrambling frequency can be changed SET SOP This option generates and maintains a user set state of polarization SOP against fluctuations in input polarization state The desired polarization state is set via Stokes parameters When this option is selected the LCD displays the following screen 1 1 00 S2 0 00 S3 0 00 SIGN Use the left and right arrow keys to move to the first Stokes parameter to be set Set the value for the first parameter and then press ENTER The cursor will advance to the next Stokes parameter Use the arrow keys to set the desired value Document GP UM PMD 1000 21 Page 30 of 122 for the second Stokes parameter Press ENTER If the first two values set are incompatible with a valid SOP the screen will display an error message Otherwise the cursor will advance to the SIGN position Use the up and down arrow keys to set the desired sign or for the third Stokes parameter and press ENTER The PMDPro will calculate and display the third Stokes parameter using the values input for the first two Stokes parameters and will execute the SOP setting The cursor will move to the bottom right corner of the screen while the PMDPro is maintaining the selected SOP To select a new SOP us
71. degradation caused by DGD and SOPMD Document GP UM PMD 1000 21 Page 115 of 122 Section 6 Troubleshooting The following table lists some of the major troubleshooting procedures Symptom Possible Solution a PMDPro does not 1 Check the power supply indicator light One nner 2 Check the operation mode o l 3 Check whether the PMDPro is in a setup or function function execution state 1 Check the measurement setup polarization analyzer or B other techniques make sure the measurement The measured PMD parameters are reasonable e g wavelength step does not match the set 2 Check the operation range 90 or 180 ps and value corresponding SOPMD table 1 Make sure that no sudden external force or vibration was C applied to the instrument The performance of 2 Use the DGD or PMD scan function to find out how the device changes many states are out of order This information indicates suddenly e g large the possibility of damage to the optical components sudden increase in inside the device loss 3 Ifthe problem persists the control circuit of the module may have been damaged A panel state 1 The static Ethernet parameters cannot be set from the ve front panel Use the GP_SET ETHERNET LabView Ethernet setup doesn t ore ork program to perform the static Ethernet setup E 1 Check the language settings of the control computer It The control program does not function properly sho
72. der the pull down menu and clicking elsewhere on the screen Then click Enable Scrambling 5 2 PMD Mitigation in 40Gb s systems As the bit rate of fiber optic communication systems increases from 10 Gbps to 40Gbps 100 Gbps and beyond polarization mode dispersion PMD has more and more impact on system performance PMD generally causes the two principal polarization components of a light signal to travel at different speeds and hence spreads the bit width of the signal as shown in Figure 29A Consequently it causes an increase in bit error rate BER and service outage probability Unlike other system impairments such as chromatic dispersion CD the PMD effect on the system is random in nature and changes rapidly with time making it difficult to mitigate Document GP UM PMD 1000 21 Page 105 of 122 Power DOP 0 t Power DOP 1 t Power DOP 1 t Figure 29 Illustrations of the PMD effect on an optical signal A The SOP of the input signal is aligned 45 degrees from the PSP of the fiber link causing the worst case signal distortion In this case if the DGD is larger than the width of one bit then the DOP 0 because the two orthogonal polarization components have the same power with no phase relationship B and C The SOP of the input signal is aligned with the slow or fast PSP axis respectively In these cases no signal distortion occurs except the slight late or early arrival respectively of the pulse The DOP o
73. direct connection a cross linked network cable must be used Note Static IP can also be used with the instrument connected to a router In this case a straight linked network cable would be used b Dynamic IP the DHCP server assigns the instrument an available address when requested Connect the instrument with a DHCP server router or exchange server as shown in Figure 25 For this configuration a standard straight linked network cable must be used Document GP UM PMD 1000 21 Page 50 of 122 DHCP server PC PMDPro Switch Be PMDPro Figure 24 Direct connection PMDPro to PC Figure 25 Connect PMDPro with DHCP server 2 Request IP address There are two ways to select the IP mode dynamic or static and request dynamic or query static the IP address Front Panel As described in section 4 2 the user can set the PMDPro for static or dynamic IP addressing and query the IP address from the front panel SETUP menu Press the SETUP button on the front panel GET DYNAMIC IP sets the PMDPro for dynamic IP addressing and requests a dynamic IP address from the server GET STATIC IP sets the PMDPro for static IP addressing and requests the static IP address stored in memory LabView Program The GP_SET ETHERNET program can also be used to obtain the dynamic IP address or the full set of static IP network settings 3 Set IP address static mode only The LabVIEW program GP_SET_ETHERNET vi or GP_SET_ETHERNET exe must be used to
74. dvanced PMDE 9 PMD Measurement 323 Long Term PMD Monitor Output DOP Setup Store Recall PMD Calculation Exit F9 Command Press Send mand to PMD 1000 Response ASRL4 INSTR Ci m Store DGD measurement To perform a DGD measurement and store the result select the memory location in which to store the data Memory Loc ID box Click the Start button The PMDPro will perform the measurement and store the results to the selected location The indicator boxes immediately below the Memory Loc ID box will display the data DGD SOPMD input and output DOP after the measurement is completed Recall PMD measurement results from memory To recall stored PMD measurement results and display them in the table on screen specify the range of memory locations to be queried by selecting the start and end ID s from the corresponding boxes to the left of the data table Then click the RECALL button to display the data on screen Document GP UM PMD 1000 21 Page 91 of 122 PMD Calculation For a particular PMD index number in the discrete lookup table this function displays the calculated wavelength dependence of the DGD and total SOPMD as well as the depolarization and polarization dependent chromatic dispersion PDCD components of the SOPMD PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 PMD Calculation
75. e between digits and the up and down arrows to increment the selected digit The ENTER key sets the number of cycles to the displayed value e INTERVAL This option sets the dwell time per sample in ms Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit The range is 1 to 9999 ms The ENTER key selects the displayed value 6 SCAN PMD MEM BANK Scan through a user generated sequence of PMD values There are 5 memory banks labeled A E each with 100 storage locations therefore up to 5 sequences of PMD values can be stored and used for this scan See the STORE menu section for instructions on storing sequences of PMD values The PMDPro will scan through the memory locations in the selected bank in order starting at the selected beginning point and ending at the selected end point The setup screens for a memory bank scan are as follows a START SCN BNK b SCAN PMD MEM BNK A c BGNA 00 ID 0039 d ENDA 99 Contin e INTERVAL _ 1000 ms f CYCLES _ 10 Use the up and down arrows to move between scan setup options and the ENTER key to access the setup screen for the selected option Document GP UM PMD 1000 21 Page 27 of 122 a START This option starts the scan Use the other options to perform the setup then return to option a to begin the scan During the scan if a discrete mode PMD value is stored at the current location the screen displays
76. e ee Document GP UM PMD 1000 21 Page 70 of 122 PMD Emulation 1 and 2 4 order The PMD emulation function generates a Maxwellian distribution of DGD values and a statistical distribution of SOPMD values corresponding to the generated DGD PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 Ganoral Dhatane TVi s liwawinw gt Continuous PMD Polarization Control Scan Stored PMD PMD Emulation PMD Scan PMO 5 PMO Distribution DGD Distribution Average DGD Sampie in Jio SOPMD Step DGO Step gnr SH Monitor Scan Mode Random Y Manual Cycle num gt Advanced PMDE eeaeee SOPMD Generated PMD Distribution PMD Measurement o Cycle Long Term PMD Monitor pai 1 Output DOP Setup Store Recall PMD Calculation Exit F9 J Command Press Send mand to PMI 1000 Response aa Sa Selection parameters Average DGD average DGD value in ps for the distribution Range 0 30 ps for 90 ps PMDPro 0 60 ps for 180 ps PMDPro Sample Total number of samples to be included in the distribution SOPMD Step Minimum SOPMD step size in ps to be used in distribution DGD Step Minimum DGD step size in ps to be used in distribution Scan Mode Determines the order in which DGD values within the distribution will be generated Random DGD values are generated in random order Sorted DGD values are generated in order from lowest to hi
77. e over it and scroll up or down After the scan is finished the data can be saved to a file by clicking SAVE DATA Data is saved as a text file with 3 columns DGD SOPMD and DOP Document GP UM PMD 1000 21 Page 79 of 122 PMD Measurement and Long term Monitoring The functions contained in these two categories are designed to measure and or monitor the PMD in a system PMD Measurement The functions in this set measure the PMD in the system under test using the PMDPro s PMD compensation function They scan through a selected set of PMD values and optimize the SOP at each state in the scan to determine which PMD value in the set can best compensate the PMD in the system That PMD value is the measured PMD for the system under test There are two tabs under this function set PMD Measurement This function uses the quasi continuous PMD generation mode to scan through a selected set of PMD values and optimize the SOP at each state in the scan to maximize the output DOP It allows the user to scan through a selected DGD range with fixed SOPMD or a selected SOPMD range with fixed DGD to perform a 2 D DGD SOPMD grid scan or to scan through a table of user set DGD SOPMD pairs Select the desired scan function from the scan setting pull down menu as shown in the picture below Scan DGD only Scan SOPMD only lt Scan DGD and SOPMD Scan DGD SOPMD value in table Document GP UM PMD 1000 21 Page 80 of 122 Sca
78. e program monitors the progress of the emulation As each point is generated the status block at the lower left of the screen Document GP UM PMD 1000 21 Page 69 of 122 shows the DGD and SOPMD sample number number of completed cycles and input and output DOP The generated DGD distribution plot shows all points generated so far When the emulation is complete it will match the calculated DGD distribution plot above it The DOP vs DGD graph plots the output DOP vs DGD for all generated points For dwell time values gt 1 s the WSOP function is also available Click the WSOP Enable button at the bottom left of the screen before starting the emulation to enable automatic polarization optimization for the worst case PMD effect at each DGD value Please note that the WSOP function is only effective for single polarization signals For dwell time values lt 1 s the WSOP and scan monitoring functions are disabled The monitor plots are replaced by a progress bar Polarization Optimized PMD Source PMD Control Program Ver 2 0 Continuous PMD Polarization Control Scan Stored PMD PMD Emulation PMD Scan DGD only z j DGD Distribution Average DGD Sample Monitor Manual Advanced PMDE taneous stantaneous DGI si PMD Measurement Long Term PMD Monitor Setup Store Recall PMD Calculation Generated DGD Distribution 4 Exit F9 ASRL4 INSTR Con adi Press S mand to PMID 100 Response ie ee
79. e the left and right arrow keys to move the cursor back to the Stokes parameter setting positions 3 6 STATE GENERATE This is a shortcut function that allows the user to simply select one of 6 SOP states commonly used for measurements the 6 Poincar sphere pole points rather than having to enter the Stokes parameters from the SET SOP screen When this option is selected the LCD displays the following screen a START SOP 6 Sta b STATE Angle 0 a START Selecting option a implements the SOP setting selected in option b The PMDPro will generate and maintain the selected SOP The 6 state generation operation screen is shown below SOP 6 STATE 0 0 00 ps 0 0 ps2 The top line shows the SOP setting 0 linear in the example above The bottom line displays the current DGD and SOPMD b STATE Angle This option specifies the SOP to be generated Use the up and down arrows to cycle through the 6 options 0 linear horizontal polarization 45 linear polarization oriented at 45 90 linear vertical 45 linear polarization oriented at 45 RHC right hand circular LHC left hand circular The ENTER key selects the displayed option Document GP UM PMD 1000 21 Page 31 of 122 4 TRACE SCAN In this function the PMDPro s polarization controller traces out a great circle on the Poincar sphere about the selected axis The setup screens for SOP trace scanning are as follows a START SOP Scan
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81. ed pattern on the Poincar sphere Certain frequency combinations will cover the entire sphere This can be a basis for polarization scrambling Figure 18 21 show some examples Figure 18 Sine wave with A 60V f 5Hz on channel 1 Figure 19 Sine wave with A 60V f 5Hz on channel 1 Sine wave with A 60V f 5Hz on channel 2 Sine wave with A 60V f 1Hz on channel 2 Figure 20 Sine wave with A 60V f 5Hz on channel 1 Figure 21 Sine wave with A 60V f 5Hz on channel 1 Sine wave with A 60V f 1Hz on channel 2 Saw wave with A 30V f 3Hz on channel 2 Sine wave with A 60V f 3Hz on channel 3 Square wave with A 20V f 2Hz on channel 3 Document GP UM PMD 1000 21 Page 36 of 122 The operation screen for the SOP waveform function is shown below CHANNEL 4 Amp _ _0 0V F __0 0 Hz W Sine Use the left and right arrows to move the cursor and the up and down arrows to change settings or values at the current cursor position CHANNEL Select polarization controller channel to be controlled Use up and down arrows to scroll through CH 1 4 Amp Set amplitude for waveform for selected channel Range 0 0 150V F Set frequency for waveform for selected channel Range 0 0 120 Hz W Select waveform type for selected channel Use up and down arrows to scroll through choices Sine Triangle Square When the waveform parameters are set up for all channels to be used press the ENTER key to begin waveform generation The cursor will move to
82. ed values he can press the ENTER key again to execute the setting and change the output DGD and SOPMD to the calculated values The LCD will display DGD 31 04 E 31 10 SOPMD _ 530 0 E 530 0 where the E indicates that the calculated values have been enabled From either the calculation or execution screens the left arrow key can be used to return to the setting mode the C or E will change back to the lt symbol and change the requested DGD and SOPMD values To observe the effect of the generated PMD on the input signal press the MONITOR button The display returns to the series of three screens showing respectively the SOP and DOP observed by the input polarimeter before the PMD generation element the SOP and DOP observed by the output polarimeter after the PMD generation element and the output power level and current DGD and SOPMD value Use the up and down arrow buttons to move between the monitor screens 3 SCAN DISCRETE PMD Discrete mode DGD or PMD scan This mode allows the user to set up a scan through either a selected subset of the DGD values in the lookup table or through all of the DGD SOPMD pairs in the lookup table in order of index number The setup screens for this option are as follows a START Scan PMD b MODE Discrete PMD c INTERVAL __100ms 1 d CYCLES _ 10 Document GP UM PMD 1000 21 Page 19 of 122 e RNG _5 0 60 0 ps set min and max t Use the up and down ar
83. educe the PMD effect on the signal after the Document GP UM PMD 1000 21 Page 106 of 122 optical signal is converted into an electrical signal However because the electrical signal does not contain the phase information of the corresponding optical signal the resulting PMD effect reduction is limited Optical PMD compensation is another attractive approach An optical PMD compensator generally contains one or more polarization controllers a PMD generation device a PMD monitoring device and a microprocessor based circuit as shown in Figure 30 The circuit receives an error signal from the PMD monitoring device and instructs the PMD generation device to adjust the PMD values and the polarization controller to adjust the polarization state input to the PMD generation device to minimize the error signal from the PMD monitoring device The PMD is compensated when the PMD generated by the PMD generating device is the same in value as that of the fiber link but with its slow axis aligned with the fast axis of the fiber link PMD Compensator Circuit amp Control Algorithm Figure 30 Optical PMD compensation The DOP measured by the polarimeter is used as PMD effect indicator The final approach is polarization multiplexed coherent detection Because the detected electrical signals in this approach contain all of the amplitude phase and polarization information of the corresponding optical signal any optical signal impairments i
84. eens for first and second order PMD emulation are as follows a START PMD Emula b AVERAGE PMD 10 0ps c SAMPLE NUM 1000 d CYCLE NUM _ 10 e INTERVAL 2000 ms Tf Rng 1 ms to 9999 ms Use the up and down arrows to move between scan setup options and the ENTER key to access the setup screen for the selected option a START This option starts the emulation Use the other options to perform the setup then return to option a to begin generating PMD values During the emulation the screen displays 9 72 ps 436 75 ps2 CY 0 SAM 80 Top line current DGD and SOPMD CY number of completed cycles SAM current sample number b AVERAGE PMD This option specifies the average DGD value for the Maxwellian distribution Use the left and right arrows to move between digits and the up and down Document GP UM PMD 1000 21 Page 26 of 122 arrows to increment the selected digit The range for average DGD is 0 0 to 30 0 ps for the 90 ps PMDPro and 0 0 to 60 0 for the 180 ps PMDPro The ENTER key selects the displayed value c SAMPLE NUM This option specifies the number of samples in the distribution Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit The range is 1 to 9999 The ENTER key selects the displayed value d CYCLE NUM This option sets the number of times to run the emulation The cycle range is 1 99999 Use the left and right arrows to mov
85. eft and right arrows to move between digits and the up and down arrows to increment the selected digit The ENTER key sets the number of cycles to the displayed value Document GP UM PMD 1000 21 Page 20 of 122 e RNG This option appears only if DGD Only is selected for option b It allows the user to set the lower and upper DGD limits for the scan Range 0 0 to 91 0 for 90 ps PMDPro 0 4 to 182 4 for 180 ps PMDPro 4 PMD TRACE SCAN Continuous mode PMD scan Unlike the discrete mode scan which generates a series of discontinuous PMD states according to the lookup table the continuous mode scan varies the PMD continuously with a user controllable variation rate This function is therefore ideal for PMD tracking speed tests The DGD SOPMD combinations available in quasi continuous mode are points on one of the characteristic SOPMD vs DGD curves 90ps PMDPro q Q A O 7 ox 40 60 80 DGD ps Figure 7 Characteristic SOPMD vs DGD curves In the PMD Trace scan function the PMDPro traces out a demi arc of a characteristic curve Each demi are is half of a characteristic curve with one endpoint on the DGD axis as illustrated in Figure 7 The user selects a particular demi arc to be traced by specifying a DGD value The PMDPro then matches the specified value to the demi arc with the DGD axis endpoint closest to that value The PMDPro can also step through a series of points along a demi
86. emulation run PME EMU CYC cyc Set number of cycles to run the emulation E00 if successful See Table 2 for Range to 99 999 other error code definitions PME EMU CYC Query PMD emulation cycle number setting cyc Default 10 cycles Example 1000 PME EMU INT int Set dwell time per point for emulation E00 if successful See Table 2 for Interval Range to 99 999 ms other error code definitions PME EMU INT Query dwell time setting Example 1000 Units in ms Default 100 0 ms Interval Range 1 TO 99 999 ms SOP RAN ENA Begin enable random scrambling EOO if successful See Table 2 for other error code definitions SOP RAN DIS Stop disable random scrambling EOO if successful See Table 2 for other error code definitions SOP RAN FRQ Query random scrambling frequency setting 123 Results are in Hz SOP RAN FRQ frqi Set frequency for random scrambling in Hz Range 1 to 6000 EOO if successful See Table 2 for other error code definitions SOP TRI FRQ Query triangle scrambling frequency setting 331 14 Results are in Hz SOP TRI FRQ frq Set frequency for triangle scrambling in Hz E00 if successful See Table 2 for Range 0 01 to 500 0 default 100 0 other error code definitions SOP TRI ENA Begin enable triangle wave scrambling E00 if successful See Table 2 for other error code definitions SOP TRI DIS Stop disable triangle wave scrambl
87. ent interface is something other than GPIB Document GP UM PMD 1000 21 Page 88 of 122 Store Recall This screen is used to store PMD sequences for scans or PMDC measurement results to memory or to recall stored data from memory PMD 1000 182 ps Polarization Optimized PMD Source Seral Number 060 PMD Control Program Ver 2 0 PMD RECALL STORE Memory Bank PMD Value in the Memory a IB Jc CJD JE Sequence Discrete PMDID DGO SOPMO ontnuous ps ps2 a jumber BO Monitor aT Memory Start ID Memory End ID Advanced PMDE PMD Meas ent w e lealulalulnl lo ze Pl Long Term PMD Monitor Setup ele s SlelelHlolo oS njet Exit F9 y Command Press Send mand to PMI 100 Response rr a T PMD Memory Bank Store Recall The PMD 1000 has 5 memory banks with 100 locations each for PMD sequence storage The user can thus store up to 5 sequences of PMD values which can be used for the Scan Stored PMD function PMD sequence storage To store a PMD sequence first select the desired memory bank A E Enter the values to be stored into the table at the right of the screen Sequence Number Memory location index number Discrete Continuous 1 0 Indicates whether a discrete or a continuous mode PMD value is to be stored at that location 1 Discrete lookup table value 0 Continuous PMD value PMD ID If a discrete value is to be stored at the cur
88. er level at the output polarimeter in mW uW and dBm and the DGD and SOPMD values currently being generated by the PMDPro in ps and ps respectively If no light is detected the PMDPro will display a Power Low message instead of the information described above Pressing the MONITOR button from any other operation or setup mode will stop any active polarization control or DGD scanning and return the display to this set of display screens The polarization controller and PMD element will be left in their most recently set states Most of the function keys under the LCD display are used to access function menus to set up the various functions of the PMDPro The menus and screen sequences are as follows Document GP UM PMD 1000 21 Page 12 of 122 4 2 2 SETUP Pressing the SETUP key accesses a setup menu that allows the user to configure the GPIB address range 1 30 and operating wavelength 87 ITU grid channels for the C band model to query the IP address and to clear the PMD sequence memory banks When the SETUP key is pressed the LCD displays 6 menu options on 3 screens 1 ITU FREQ CHANNEL 2 GPIB ADDRESS l 3 GET DYNAMIC IP f 4 GET STATIC IP l Note the next to the dynamic or static IP line indicates the PMDPro s current Ethernet communication mode In this example the PMDPro is set for dynamic IP addressing 5 SET STATIC IP T 6 INIT PMDE MEM BANK Use the up and down arrow keys to move between menu o
89. ess ENTER to store the data at that location After the data is stored the display will return to the PMDC mode selection screen Document GP UM PMD 1000 21 Page 44 of 122 4 2 9 RECALL This mode allows the user to recall previously stored sequences of PMD values or PMD compensation data The screen interfaces are almost identical to those of the STORE function When the RECALL button is pressed the LCD displays the following screen 1 PMDE Rcl Seq Bnk A 2 PMDC RECALL RESULT 1 PMD SEQUENCE This option allows users to see the contents of any of the 5 PMD sequence storage banks With the cursor on option 1 press the ENTER key to select it The cursor will move to the bank index A E location Use the arrow keys to select the desired storage bank and then press ENTER The LCD displays the following screen if a discrete mode PMD value is stored at the current memory location A Disc ID 0039 Lo 00 3 57ps 0 0ps2 The letter in the upper left corner indicates the selected storage bank A in this example Lo is the memory location index ID is the PMD index number of the value stored at that location the DGD and SOPMD corresponding to the index are displayed in the bottom line of the screen The arrow keys can be used to change the memory location index to look at the contents of other locations If the value stored at a particular location is a continuous mode PMD value the display changes to A Cons Recall Loc 05 D
90. f the signal remains at 1 In all 3 cases the PMD of the link remains the same but the effect on the signal is different due to the different input polarization states Several methods with varying success rates exist to mitigate PMD effects for 40G deployment The first is to select fiber routes with low PMD coefficients Such a method requires extensive survey of all available fiber routes to identify and cherry pick those with sufficiently low PMD However such an approach has three potential drawbacks First the PMD of a fiber route changes with time as the environmental conditions around the fiber change Such changes can include land movements caused by earthquake flood or mud slides A route that is good today may become bad in the future Second interconnected fiber routes may always have bad fiber sections with high PMD rendering the selection of low PMD fiber routes throughout the system impractical Finally the supply of fiber routes with low PMD values will eventually be exhausted as 40G deployments increase The second method is to use bandwidth efficient modulation formats such as DPSK or DQPSK Such modulation formats reduce the effective bandwidth of a 40Gb s channel to that of a 20Gb s or even a 10Gb s channel Consequently the impact of PMD on the signal is greatly reduced though never eliminated The third approach is electronic PMD compensation in which forward error correction FEC or other algorithms are used to r
91. generation speed minimum time interval around ms resulting from the high speed switching of the ternary polarization rotators This high speed operation can speed up PMD tolerance tests and can be used to test the response time of a PMD compensator against sudden PMD changes Automatic optimization of input polarization for worst case 1 order and 2 order PMD tolerance tests regardless of rapid polarization changes before the input to the PMD source The polarization optimization eliminates test uncertainties and significantly reduces the time required to complete tests It is therefore ideal for PMD tolerance tests for transceiver production lines as shown in Figure 31 PMD compensation using either an automatically optimized PMD value or a user selected PMD value The PMD compensation is accomplished by maximizing the DOP detected by the polarimeter at the output port Both PMD and DOP values will be shown on the front panel LCD display By stepping the PMD values up and down and looking at the maximized DOP values the user can directly see how the PMD value chosen affects PMD compensation When optimized PMD mode is selected the instrument will go through all PMD states and search for the maximum DOP The PMD state with the maximum DOP is selected as the optimized PMD for PMD compensation PMD value determination of an in service fiber link The optimized PMD compensation mode can be used to determine the PMD in the link as shown in
92. gh a selected DGD range with fixed SOPMD a selected SOPMD range with fixed DGD perform a 2 D DGD SOPMD scan or scan through a user defined list table of DGD SOPMD pairs All of these functions can be performed with automatic worst case SOP search enabled or disabled Scan DGD only Scan SOPMD only lt Scan DGD and SOPMD Scan DGD SOPMD Table Document GP UM PMD 1000 21 Page 75 of 122 Select the desired scan function from the pull down menu as shown in the picture above To enable worst case SOP optimization click the WSOP Enable button at the bottom left of the screen before running a scan To disable it select Disable WSOP Please note that this function can only be used with single polarization signals Scan DGD only This function scans through a user defined DGD range with a fixed SOPMD value PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 Continuous PMD Polarization Control Scan Stored PMD PMD Emulation PMD Scan PMO Trace Scan Local PMD Scan Ly San GD Instantaneous DGDips Instantaneous SOPMD px2 Output DOP PMDC Jo 04 92 Stop DGD _ ee Monitor Ae DOP DGD SOPMD DGD Step g Fixed SOPMD fo Manual Advanced PMDE PMD Measurement Long Term PMD Monitor 0 Setup 0 5 WEDS WIS 45 5 550 0co Store Recall PMD Calculation Exit F9 ASRL4 INSTR Con nd Press S 1000 i a
93. ghest Interval dwell time in s per sample Minimum value is 0 001s However data will only be plotted for dwell times gt 1s Cycle Num Number of times to run the scan The plots in the top row show the calculated distributions of values for the emulation The PMD distribution plot shows DGD vs SOPMD with the color indicating the frequency of occurrence of a particular set of values This is a 3D plot that can be rotated or zoomed for viewing from different perspectives as shown below To rotate a 3D graph drag it with the mouse To zoom in or out hover the mouse over it and scroll up or down Document GP UM PMD 1000 21 Page 71 of 122 PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 Continuous PMD Polarization Control Scan Stored PMD PMD Emulation PMD Scan PMO Ay PMO Distribution DGD Distribution SOPMD Distribution Average OGD Sample z 5 Jax 9 1000 T gt J 0 PMDC e Step DGO steo z 2 E 30 Jx 92 A 7 3 Monitor Sean Mode T ndom y 10 Manual wl t e o 0 ji a 2 E nae so 1001500 a SOPMO ntaneous eous D nl Advanced PMDE Gen SOPMD Distnbuton PMD Measurement Long Term PMD Monitor Setup Store Recall PMD Calculation Exit F9 y Con Press Send to transmit command to PMD 1000 R 1 Ge D The DGD distribution plot shows the calculated distribution of DGD values that corresponds to the selected p
94. he trace list to highlight it then click the Delete Trace button in the middle left section of the screen Document GP UM PMD 1000 21 Page 73 of 122 PMD 1000 182 ps Polarization Optimized PMD Source PMD Control Program Ver 2 0 Gonoral of Continuous PMD Polarization Control Scan Stored PMD PMD Emulation PMD Scan PMD Trace Sean Local PMO Scan Trace List Index DGD SOPMD DGD SOPMD Start Start End End Instantaneous OGD 4847 psinstantaneous sopmD 279066 p2 Cyder 9 E 109 10991 55792 oo 9653 BRS oo 91 40 99 SOPMD ps2 Advanced PMDE Start SOPMD a Dras PMD Measurement End SOPMO aa 8 Le Long Term PMD Monitor Step Direction Cycle Type wW vi Bideo z Cycle Number Store Recall F Scan Rate PMD Calculation A g2 s Setup Exit F9 Pre nand to PMID 1000 y m ad to transmit commn Response ec E The Scan Setting block on the lower left of the screen is used to configure the operational parameters for the scan Scan Setting Scan Mode Step Direction Cycle Type EET e eeen i Step The scan mode pull down menu allows the user to choose between a continuous or step scan In a continuous scan the PMDPro uses the smallest possible DGD step size 0 1 ps to generate the trace and the user can select the rate of change of DGD in ps s In a step scan the PMDPro generates a series of points placed along the tra
95. hen return to option a to begin generating DGD values During the emulation the screen displays CURRENT DGD 37 49 ps CY 0 SAM 80 CURRENT DGD current DGD value in ps CY number of completed cycles SAM current sample number b AVERAGE DGD This option specifies the average DGD value for the Maxwellian distribution Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit The range for average DGD is 0 0 to 45 4 ps for the 90 ps PMDPro or 0 to 91 2 ps for the 180 ps PMDPro The ENTER key selects the displayed value c SAMPLE NUM This option specifies the number of samples in the distribution Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit The range is 1 to 999999 The ENTER key selects the displayed value Document GP UM PMD 1000 21 Page 25 of 122 d CYCLE NUM This option sets the number of times to run the emulation The cycle range is 1 99999 Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit The ENTER key sets the number of cycles to the displayed value e INTERVAL This option sets the dwell time per sample in ms Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit The range is 1 to 60000 ms The ENTER key selects the displayed value B PMD EMULATION The setup scr
96. ide the boxes The program will match the closest lookup table Document GP UM PMD 1000 21 Page 58 of 122 DGD values to the ones entered Click Start to start the scan During the scan the current DGD value in ps is displayed in the box at the right of the screen SCAN PMD The PMD 1000 scans all DGD SOPMD pairs in order of their index number see lookup table for corresponding values Set the desired dwell time per point Scan Interval and number of times to run the scan Cycle and then click Start to start the scan During the scan the current PMD index number and the corresponding DGD and SOPMD values are displayed Document GP UM PMD 1000 21 Page 59 of 122 WSOP This function combines the PMDPro s discrete PMD generation function with its automatic polarization control function The polarization controller is used to tune the input SOP to the PMD generation element to obtain the worst case DGD or PMD effect for a given DGD and or SOPMD value 2 ne MD 1000 182 ps Polarization Optimized PMD Source PMD Control Program Ver 2 0 Ganoral Photonies PMDE WSOP PMD SETTING SOP r PMD D 89 63 9 ps SOPMD 0 ps 2 PMDC Monitor EQUAL POWER SPLIT FOR INPUT RE INPUT DOP 100 2 Ca OUTPUT DOP e PMD Measurement Long Term PMD Monitor OPTIMIZE OUTPUT DOP TO MIN Setup INPUT DOP 0 C6 OUTPUT DOP C Store Recall PMD Calculation Exit F9 y ASRL INSTR Command Press
97. ime of 0 5 s or to exit the scan and return to parameter setup As the values stored in this memory range include both discrete and continuous PMD values the minimum scan interval is 0 5s Run 0 5s scan interval Note also that if the selected dwell time is lt 1 s the scan will run but the points will not be plotted on the display Select the number of times to run the scan Cycle and then click Start to start the scan For dwell time settings gt 1s as the scan progresses each point is plotted on the graph as it is generated and its DGD and SOPMD values are displayed above the graph PMD Emulation This function performs statistical first order or first and second order PMD emulation to simulate the PMD in real systems For single polarization signals the SOP can also be automatically optimized for worst case PMD effect at each PMD value Select DGD only SOPMD 0 or PMD DGD SOPMD emulation from the pull down menu at the top left of the operation area of the screen DGD only l PMD PMD Emulation DGD only The DGD only PMD emulation function generates a Maxwellian distribution of DGD values with SOPMD 0 Document GP UM PMD 1000 21 Page 68 of 122 PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 Continuous PMD Polarization Control Scan Stored PMD PMD Emulation PMD Scan Doy vf DGD Distribution Average
98. ing E00 if successful See Table 2 for other error code definitions SOP SSS sJ 52 s3 Set S1 S2 and S3 Range for S1 S2 and S3 1 000 to 1 000 EOO if successful See Table 2 for other error code definitions SOP SS1 Query the set value of S1 Return 0 463 Example SOP SS2 Query the set value of S2 Return 0 123 Example SOP SS3 Query the set value of S3 Return 0 423 Example SOP SSS ENA Execute SOP setting If no Stokes parameters were entered or if an incorrect set of Stokes parameters was entered executes setting 1 0 0 EOO if successful See Table 2 for other error code definitions SOP SSS DIS Disables active SOP maintenance returns to Stokes setting screen EOO if successful See Table 2 for other error code definitions Document GP UM PMD 1000 21 Page 96 of 122 SOP SPL STA Query the special SOP state setting current or most recently set O 45 45 90 RHC LHC SOP SPL 0 SOP SPL 45 SOP SPL 45 SOP SPL 90 SOP SPL RHC SOP SPL LHC Set SOP to one of 6 special states 0 0 linear 45 45 linear 90 90 linear 45 45 linear RHC Right Hand Circular LHC Left Hand Circular Special SOP polarization control E00 if successful See Table 2 for other error code definitions SOP TRA SPD time Set SOP trace scan speed dwell time per point in ms Range t
99. ing the front panel See the remote control section for details on program installation and hardware setup After running the program the user can set the PMD value either using the discrete lookup table or using the quasi continuous PMD control function Discrete control using lookup table 1 Click the PMDE button on the left function panel to bring up the main PMDE interface Document GP UM PMD 1000 21 Page 103 of 122 Polarization Optimized PMD Source PMD Control Program Ver 2 0 General Photonics PMD 1000 182 ps SET PMD DGD MAXWELLIAN DISTRIBUTION PMDC Scan Interval Cycle Num a a Monit L onitor 100 y 10 Manual SCAN DGD SOPMD 0 Advanced PMDE Scan Interval 100 PMD Measurement a Long Term PMD Monitor y SCAN PMD Setup Scan Interval A 100 Store Recall PMD Calculation y Exit F9 2 Set the PMD ID in the top block of the interface screen The corresponding DGD and SOPMD values will be displayed as the index number is updated and the output PMD updates in real time 3 Click the SOP button on the left function panel to bring up the polarization control interface screen Polarization Optimized PMD Source PMD Control Program Ver 2 0 SCRAMBLING PMDC Monitor Manual SET SOP Sig 1 000 Vy Th f S1 52 and 3 must be 1 Advanced PMDE e Square sum o must be equal to PMD Measurement 6 STATE GENERATOR Long Term PMD Monitor Setup TRACE SCAN S
100. ion sets the dwell time per step Use the left and right arrow keys to move between digits and the up and down arrow keys to increment the active digit The range is 1 to 60 000 ms The ENTER key selects the displayed option STEP This option sets the step size in degrees Use the left and right arrow keys to move between digits and the up and down arrow keys to increment the active digit The range is 0 1 to 64 4 The ENTER key selects the displayed option Document GP UM PMD 1000 21 Page 33 of 122 5 WAVE MODE This option allows the user to independently set periodic waveform control signals for 4 channels of the polarization controller This gives the user the flexibility to switch back and forth between two SOPs square wave on one channel to set up a constant rate SOP variation triangle wave on one channel or to use multiple channels to implement a more complicated variation pattern Applying a sine wave to one channel sweeps out a ring or portion thereof depending on the amplitude sinusoidally in time on the Poincar sphere Figure 10 13 show examples of this for each of the 4 channels individually Figure 10 is the trace for a sine wave with amplitude 60V and frequency 5 Hz applied to channel 1 Figure 11 is the same sine wave applied to channel 2 Figure 12 and 13 show the trace for a sine wave with amplitude 30V and frequency 5 Hz applied to channels 3 and 4 respectively Since V is about 30V the first two traces
101. is saved as a text file with 3 columns DGD SOPMD and DOP Document GP UM PMD 1000 21 Page 82 of 122 Scan DGD and SOPMD This function performs a 2 D DGD SOPMD grid scan over a user defined area PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 PMD Measurement DGD Measurement Scan Setting E ooon mineossomonn ounto E Start DGD 1941 1300 164 oa Jo OGD DOP DOP DGD SOPMO Stop DGD Monitor Manual _ Start SOPMD Advanced PMDE Jo PMD Measurement Stop SOPMD J 200 Long Term PMD Monitor so step jx Setup Store Recall Max DOP i PMD Calculation 795 Exit F9 Co y ASRL4 INSTR pe ndi Press Send to smst AD t ne el Selection parameters Start DGD DGD start value in ps Stop DGD DGD end value in ps DGD step DGD step size in ps Start SOPMD SOPMD start value in ps Stop SOPMD SOPMD end value in ps SOPMD step SOPMD step size in ps Scan Interval on top of graph dwell time per point in s Minimum value 0 4 s When the scan parameters are set click Start to start the scan At each point in the scan the DGD SOPMD and maximum output DOP for that point are displayed above the graphs and the maximum output DOP vs DGD is plotted in the graph on the left The maximum output DOP for the scan and the corresponding DGD and SOPMD values are displayed below the graph The graph on the right
102. l communication port Ethernet Ethernet interface port BNC not used in PMD 1000 GPIB GPIB interface port Line external AC supply input connector 100 240V AC L chassis ground connector Document GP UM PMD 1000 21 Page 10 of 122 Section 4 Operation Instructions Warning Never look into the light source fiber connector when the light source is turned on THE OUTPUT LIGHT FROM A HIGH POWER LASER IS HARMFUL TO HUMAN EYES Please follow industry standard procedures when operating a high power laser source Avoid water condensation or liquid spills during PMDPro storage and operation Check optical power level of the input optical beam For accurate measurements make sure the optical power level at the input connector is below 10 dBm 10 mW 4 1 Unpacking Inspect PMDPro for any physical damage due to shipping and transportation Contact carrier if any damage is found Check the packing list to see if any parts or accessories are missing Avoid high vibration environments when using the PMDPro 4 2 Front Panel Operation The conceptual structure and operational principles of the PMDPro are described in section 2 This section describes operational procedures and control sequences for control of the PMDPro s basic functions from the front panel Setup procedure is described below l Make sure local AC voltage matches the AC voltage requirement of the PMDPro If not do not proceed Contact General Photonics i
103. ler The manual operation mode allows the user to directly set the control voltages to each channel of the polarization controller rather than using the polarimeter feedback to control the polarization controller 182 ps Polarization Optimized PMD Source PMD Control Program Ver 2 0 MANUAL Voltage range is 0 0 to 150 0 Volts PMDC Monitor Manual Advanced PMDE PMD Measurement Long Term PMD Monitor Setup Store Recall PMD Calculation Exit F9 Le The voltage range for each channel is 0 150V V for each channel is about 30V Document GP UM PMD 1000 21 Page 65 of 122 Advanced Functions This function set includes more advanced PMD generation and scan functions that make use of the PMDPro s quasi continuous PMD generation capability It also includes PMD measurement and long term monitoring functions ADVANCED PMDE This operation mode combines the PMD 1000 s continuous PMD generation function with scan emulation and polarization control functions There are four tabs within this section Continuous PMD Polarization Control This is the control screen for the PMD 1000 s deterministic quasi continuous PMD generation function This function allows the user to select any DGD SOPMD combination within the area bounded by the curve PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 Continuous PMD Polarization Control Scan Stored PMD
104. lumns DGD SOPMD and DOP Scan DGD SOPMD table This function scans through a set of user defined DGD SOPMD pairs Polarization Optimized PMD Source PMD Control Program Ver 2 0 Continuous PMD Polarization Control Scan Stored PMD PMD Emulation PMD Scan PMD Trace Scan Local PMD Scan s Instantaneous DGD ps Instantaneous SOPMD ps2 Output DOP OCOips SOPMO ps2 036 04 99 Monitor pa A DOP DGD SOPMD Manual Js ao f f WSOP PMDC Advanced PMDE PMD Measurement Long Term PMD Monitor Tas Des e Hee Oe cel oe toe Setup 5sSuwuebpenmanawHnH HH DW DGD Store Recall PMD Calculation Exit F9 Commandit Press Send 00 Response ie Ss oH Enter the PMD values to be scanned in the table on the left of the screen DGD values are in ps and SOPMD values in ps As in the other scan functions the dwell time per point Scan Interval in s should be set in the box above the graph The minimum value is 0 4 s When all of the PMD values are entered into the table click Start to start the scan As each point is generated the DGD SOPMD and output DOP are displayed above the graph and the output DOP vs DGD is plotted in the graph on the left The graph on the right is a 3D graph of DOP vs SOPMD and DGD It can be rotated or zoomed for viewing from different perspectives To rotate a 3D graph drag it with the mouse To zoom in or out hover the mous
105. max Range for min and max 0 to 255 min lt max E06 if values out of range See Table 2 for other error code definitions LCD display will update PME SCN DGD Query DGD scan limits Range Boundaries Min 0 and Max 255 DGD ID s of start and end points Example 84 255 PME SCN PMD Discrete mode PMD scan Scan through all PMD values in lookup table in order of index number i e from 0 to 6560 E00 if successful See Table 2 for other error code definitions LCD display will update PME CUR PMD Query Current PMD ID during a discrete mode DGD or PMD scan 46 PME SCN SPD time Set the dwell time per point in ms for discrete mode DGD or PMD scan Range 1 to 60000 EOO if successful See Table 2 for other error code definitions PME SCN SPD Query dwell time per point in ms for discrete mode DGD or PMD scan 346 PME SCN CYC cyc Set the number of times cycles to run a scan Discrete scan or continuous step trace Range 1 to 9999 EOO if successful See Table 2 for other error code definitions PME SCN CYC Query scan cycle number setting 485 PME SCN CYC CUR Query Current Cycle count Number of completed cycles Example 85 PME SCN CON ENA Begin Continuous Trace Scan using current settings EOO if successful See Table 2 for other error code definitions PME SCN CON DIS Disable stop Continuous Trace
106. ment of the PMD in the system The top line displays the measured DOP at the input I and output O polarimeters The output DOP indicates how well the system PMD is compensated The polarization controller continues to actively optimize SOP as long as the PMDPro is in this mode 3 DGD SELECTED COMP This option scans the input SOP to the PMD element to search for the maximum possible output DOP value for any given user selected DGD state When this option is selected the screen displays DOP I 33 6 O 91 5 DGD 7 14ps ID 20 The top line displays the DOP measured at the input I and output O polarimeters when the DGD SELECTED COMP function was first selected The bottom line displays the current DGD state DGD value and corresponding index number Use the arrow keys to select the desired DGD index The DGD state updates in real time as the index is changed When the desired DGD state is selected press the ENTER key to begin polarization optimization at that state The display format will remain the same but the input and output DOP values in the first line will update with their real time values Use the left arrow key to stop the SOP searching and return the cursor to the index selection position 4 PMD SELECTED COMP This option scans the input SOP to the PMD element to search for the maximum possible output DOP value for any given user selected PMD state When this option is selected the screen displays MAX DOP 92
107. mmediately The PMDPro power supply accepts 100 240 VAC 50 60 Hz line voltages Connect power cord and plug it into the wall receptacle Make sure the ground pin of the power cord is connected to earth ground Make sure the input optical power is at an appropriate level then connect input and output fibers to the PMDPro It is important to clean the fiber connectors using industry standard procedures and to make sure that the connections are good If using a high power optical source if possible turn off optical power source before connector cleaning 4 Power on the PMDPro and the optical source Document GP UM PMD 1000 21 Page 11 of 122 When the PMDPro is first powered on the LCD will briefly flash the following initialization screen which shows the model number and firmware version GENERAL PHOTONICS PMD Pro VER 2 0 4 2 1 MONITOR After the initialization is finished the PMDPro goes into monitor mode The LCD displays DOP xx xx s1 X xx S2 X XX s3 X XX This screen displays the SOP Stokes parameters and DOP information of the light as measured by the input I polarimeter The up and down arrow keys can be used to toggle through two more display screens DOP xx xx s1 X xx S2 X XX s3 X XX O The second screen displays the SOP Stokes parameters and DOP information of the light as measured by the output O polarimeter P xxx uW x xx dBm X XX PS X XXpS2 The third display screen shows the pow
108. n DGD only This function scans through a user defined DGD range with a fixed SOPMD value PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 PMD Measurement DGD Measurement Sean Setting lt Instantaneous OGD ps Instant SOPMD ps2 Output DOP Ms Scan interval 5 an 82 os _Start DGD fo FNDE DGD DOP DOP DGD SOPMO Stop DGD Monitor gjo Manual DGD Step J Advanced PMDE PMD Meas ent Long Term PMD Monitor Setup Store Recall SOPMO with DGD with Max DOP ips Max DOP ips 2 PMD Calculation 1392 0A Exit F9 Co j Press Send mand to PMED 1000 kl ASRL4 INSTR ermandit Pr Response Selection parameters Start DGD DGD start value in ps Stop DGD DGD end value in ps DGD step DGD step size in ps Fixed SOPMD fixed SOPMD value in ps Scan Interval on top of graph dwell time per point in s Minimum value 0 4 s When the scan parameters are set click Start to start the scan At each point in the scan the DGD SOPMD and maximum output DOP for that point are displayed above the graphs and the maximum output DOP vs DGD is plotted in the graph on the left The maximum output DOP for the scan and the corresponding DGD and SOPMD values are displayed below the graph After the scan is finished the data can be saved to a file by clicking SAVE DATA Data is saved as a text file with 3 col
109. n a PMD source because they enable fast repeatable PMD tolerance tests and PMD compensator evaluation Automatic optimization of input SOP is also highly advantageous As described previously PMD tolerance tests can be greatly simplified if the input SOP to the PMD elements inside a PMD source can be controlled and optimized such that each PMD value has the most severe possible impact on the quality of the optical signal regardless of polarization changes caused by disturbances to the fiber link Specifically the input SOP can be automatically maintained at an alignment of 45 degrees from the PSP of the PMD source or the output DOP can be automatically maintained at a minimum value by actively controlling the input SOP PMD compensation is also an extremely attractive function First system vendors and network operators need to know how much improvement can be made in system performance by adding PMD compensation in order to decide whether to deploy PMD compensators on a link with performance issues Second if PMD compensation significantly improves the system performance it can be determined that PMD is the major cause of performance degradation otherwise other impairments should be considered Therefore a PMD source with PMD compensation capability can be used for the diagnosis of system problems Finally optimized PMD compensation can help to determine the PMD values of the fiber link because the PMD value used for optimal PMD compensati
110. n the bottom line of the screen The value on the left side is the DGD and the value on the right is the SOPMD The PMD setting is changed in real time as the index is incremented To observe the effect of the generated PMD on the input signal press the MONITOR button The display returns to the series of three screens showing respectively the SOP and DOP observed by the input polarimeter before the PMD generation element the SOP and DOP observed by the output polarimeter after the PMD generation element and the output power level and current DGD and SOPMD value Use the up and down arrow buttons to move between the monitor screens Document GP UM PMD 1000 21 Page 17 of 122 2 SET CONTINUOUS PMD In this mode the user inputs the desired output DGD in units of ps and SOPMD in units of ps The PMDPro then calculates and displays the closest achievable match to the DGD and SOPMD values input by the user At this point the user can either choose to execute the setting or modify the requested values and recalculate When this option is selected the LCD displays the PMD selection screen DGD _ 0 00 lt 91 04 SOPMD ___0 0 lt 0 0 For both DGD and SOPMD the number to the left of the lt symbol is the value set by the user The number on the right is the maximum available value The maximum available DGD value is determined by whether the PMDPro is a 90 ps or 180 ps unit The maximum available SOPMD value is determined
111. ncluding PMD can be compensated by digital signal processing In addition because of the quadrupled spectrum efficiency resulting from QPSK modulation and polarization multiplexing the effective optical signal bandwidth of a 40G channel is about the same as that of a 10G TDM channel Consequently the PMD effect on such a narrow band signal is also greatly reduced even without PMD compensation Although transceivers incorporating polarization multiplexed coherent detection may still not be cost effective compared with other approaches for 40Gb s transmission they are most attractive for 100Gb s and higher speed transmissions Document GP UM PMD 1000 21 Page 107 of 122 5 3 Instruments required for PMD related tests PMD source for PMD tolerance test No matter which approach is taken it is desirable to have an instrument capable of testing the performance of different methods in mitigating PMD effects This test is called a PMD tolerance test The general setup is shown in Figure 31A The key instrument in this setup is the PMD source which can generate precise 1 and higher order PMD values The bit error rate BER of the system or another such performance indicator is measured as the 1 order PMD DGD values generated by the PMD source are gradually increased until the BER reaches the limit set for the system as shown in Figure 31B The corresponding DGD is the 1 order PMD tolerance of the system Both the 1 and 2 order PMD S
112. nication requires installation of an additional driver After the control program is installed and the computer is restarted connect the PMDPro to the computer with a USB cable and power on the PMDPro This should initiate installation of the USB driver Document GP UM PMD 1000 21 Page 49 of 122 If asked to specify a driver location select the USB Driver folder and make sure that include subfolders is checked 4 3 5 GPIB Connection To ensure proper communication use a GPIB cable that is fully compatible with the IEEE 488 1 standard All GPIB IEEE 488 interface connections must be made before turning on the instruments The GPIB address can be changed either from the SETUP menu of the front panel controls or from the SETUP screen of the control program if an interface other than GPIB is being used 4 3 6 Ethernet Connection The IP address from an ISP is assigned in one of two ways e Set to an IP which is only good for a limited time and which is changed according to the policy set by the ISP s DHCP server This is a dynamic IP address e Set to an IP address which can be unchanged for months or years at a time This is a static IP address Ethernet Setup 1 Connections There are two connection configurations for Ethernet control a Static IP the administrator assigns the instrument a fixed IP address In this mode the instrument can be directly connected to the control PC as shown in Figure 24 For a
113. nput power should be between 10 and 10 dBm 3 2 Electrical Features The PMDPro system uses a power supply that accepts 100 240 VAC 50 60 Hz line voltages Due to high voltage the following safety precautions must be exercised during operation e The ground pin on the power supply cord must be connected to earth ground of the wall receptacle e Never touch the boards inside the package without proper insulation e The PMDPro is not user serviceable It should be serviced only by factory authorized personnel The front panel of the PMDPro is shown in Figure 3 The power switch Power liquid crystal display LCD push button control pads and input output optical connectors are mounted on the front panel The AC power plug fuse chassis ground connector RS 232 USB Ethernet and GPIB interface connectors and two fans are mounted on the rear panel as shown in Figure 4 The PMDPro includes RS 232 USB Ethernet and GPIB interfaces for external computer operation of the system and data readout RS 232 and USB cables are provided for connecting the PMDPro to a personal computer A LabView National Instruments Www ni com control program compatible with all of the control interfaces is provided Control commands and control program installation and operation instructions are located in Section 4 3 Document GP UM PMD 1000 21 Page 8 of 122 Benes Photores PMD 1000 A PMDPro E Figure 3 Front panel layout Front panel desc
114. o 60000 Example 4000 Default Units ms Default value 100 SOP TRA SPD Query the trace scanning speed dwell time Ex 234 Default 100ms SOP TRA STP stp Set the SOP trace scan step size Units degrees Default 1 Range 0 0 to 99 9 EOO if successful See Table 2 for other error code definitions SOP TRA STP Query the SOP trace scan step size setting Ex 99 9 SOP TRA STA Query the SOP trace scan axis setting O 45 45 90 S3 0 ALL Set trace scan axis Set the trace scan axis SOP TRA 0 0 E00 if successful SOP TRA 45 45 See Table 2 for other error code SOP TRA 45 45 definitions SOP TRA 90 90 SOP TRA S3 0 S3 0 Trace equator of Poincar sphere SOP TRA ALL All Perform all 5 traces sequentially SOP MPC ENA Begin enable waveform generation with E00 if successful See Table 2 for current settings on all channels other error code definitions SOP MPC DIS Stop disable waveform generation E00 if successful See Table 2 for other error code definitions SOP CHx AMP Query Channel x Amplitude setting Sample SOP CH AMP x to4 Response 23 5 Units in Volts Amplitude range OV to 150V Default CH1 30V others 0V SOP CHx FRQ Query Channel x Frequency setting Sample SOP CH1 FRQ x l to4 Frequency range 0 Hz to 120Hz Default CH1 10Hz others 0Hz Response 12 6 Units in Hz Document GP UM PMD 1000 21 Page
115. on is close to the real PMD value of the fiber link Such a feature is attractive for frequent PMD monitoring of an in service fiber link a task that cannot be accomplished with PMD analyzers currently on the market 5 5 The polarization optimized PMD source The PMDPro meets all of the requirements described above It is constructed with a polarization controller PC a polarimeter at the input end a PMD generator a second polarimeter at the output end and a digital signal processor DSP based electronic circuit as shown in Figure 33 The two polarimeters are used to provide feedback signals to the DSP circuit for full polarization optimization The circuit receives the polarization measurements from the two polarimeters processes them then sends commands to control the PMD generator and the polarization controller The circuit can use the SOP information from the input polarimeter as the feedback to control the PC and generate any SOP the user prefers In particular it can automatically align the SOP to 45 degrees from the PSP of the PMD generator This polarization state causes the PMD generator to cause the worst case 1 order PMD DGD effect on the optical signal at any DGD setting and is therefore the preferred SOP for DGD tolerance tests for transceivers and fiber systems Alternatively the circuit can use the DOP information from the output polarimeter as the feedback to control the PC The input SOP that minimizes the output DOP ca
116. or example the arrow keys can be used to move between channels From a channel selection position pressing ENTER will move the cursor to the voltage corresponding to the current channel position Once on the voltage use the arrow keys to set the voltage for that channel left and right arrow to move between digits and up and down arrows to change the value of the selected digit The voltage range for each channel is 0 0 to 150 0V and V for each channel is about 30V The channel voltages are updated in real time as the settings are changed so that the effects of the SOP change can be observed Pressing ENTER when the cursor is on a voltage setting position will advance it to the next channel selection position Document GP UM PMD 1000 21 Page 42 of 122 4 2 8 STORE This mode allows the user to store either sequences of PMD values to be used for a sequential scan see PMDE section or PMD compensation data from any of the PMD compensation function modes When the STORE button is pressed the LCD displays the following screen 1 PMDE Str Seq BNK A 2 PMDC STORE RESULT 1 PMD SEQUENCE This option allows users to store up to 5 sequences of PMD values for use in the selected PMD scan function see PMDE section for details on how to run a scan of a stored sequence Each storage bank A E can hold up to 100 values index range 00 99 A PMD sequence stored in a bank can consist of discrete mode PMD values continuous mode PMD values
117. or a combination of the two Press the ENTER key to select this option The cursor will move to the bank index A E Use the arrow keys to select the desired storage bank and then press ENTER The LCD displays the following screen A Dsc ID 0023 Lo 00 8 21ps 0 0 ps2 The letter at the top left of the screen indicates the selected storage bank A in this example Dsc indicates that a discrete mode value is to be stored ID is the PMD index number of the value to be stored the DGD and SOPMD corresponding to the index are displayed in the bottom line of the screen and Lo is the memory location index Use the left and right arrow keys to move the cursor position and the up and down arrow keys to change the value at the current cursor position To store a discrete mode PMD value move the cursor to the ID position and use the arrow keys to set the desired PMD index The corresponding DGD and SOPMD displayed in the bottom row will update as the index is changed Then move the cursor to the Lo position and use the arrow keys to set the desired memory location Pressing ENTER from here will store the current PMD value in the currently selected memory location and increment the memory location by 1 To store a continuous mode PMD value move the cursor to the _ Dsc position and press the up or down arrow key The screen display will change to Document GP UM PMD 1000 21 Page 43 of 122 A Cts Calc Loc 00 DGD 8 21 SO __0 0
118. oss or measurement instability that does not improve after cleaning the external connectors may indicate that the instrument s internal connector ferrules require cleaning Each connector ferrule is contained in a universal connector interface consisting of a front piece that connects to the external fiber connector and a base piece that is mounted on the front panel of the instrument as shown in Figure 2 To clean a connector ferrule first make sure no external connector is connected to the universal connector interface Then using a Phillips screwdriver remove the two small screws connecting the front and back parts of the adapter and carefully pull the front flange straight out Note never remove the adapter base from the front panel The ferrule end should now be exposed Clean the ferrule using standard cleaning procedures compressed air or a fresh lint free tissue and alcohol taking care to avoid scratching the ferrule surface Finally replace the front flange position it so that the key notch faces up and the small alignment pin lines up with the hole in the base piece before pushing it in and the screws For frequent measurements we recommend that the user prepare a patch cord fiber to avoid wear on the internal connector Hole for alignment pin Remove screws Adapter base Front flange do not remove Ferrule end Figure 2 Diagram of universal connector interface Document GP UM PMD 1000 21 Page 7 of 122 I
119. own in Figure 29 By contrast when the input SOP is aligned 45 degrees from the PSP of the fiber link or PMD source the PMD has its maximum effect on the transmitted optical signal and hence its worst case effect on system performance The effect of PMD on data can be characterized by the degree of polarization DOP of the optical signal because PMD causes depolarization of the optical signal as shown in Figure 29 the smaller the DOP the larger the PMD effect In general the DOP of the signal passing through a medium with nonzero 1 order PMD can be expressed as DOP t J4 7 1 R 2 R 0 1 1 where t is the DGD value of the medium y is the power distribution ratio of the two polarization components with respect to the principal state of polarization PSP of the DGD element y 2 when the powers of the two polarization components are equal or when the input SOP to the medium is oriented 45 degrees from its PSP and R r is the self correlation function of the optical signal which decreases as t increases Clearly the DOP reaches a minimum value of R z R 0 when y or when the input SOP is 45 degrees from the PSP of the DGD medium At this SOP the PMD has its worst effect on the quality of the signal Conversely when y 1 or when the input SOP is aligned with the PSP the DOP remains at its maximum value of 1 regardless of the DGD value When higher order PMD is present the PSP is different for different waveleng
120. polarization state of the signal at the input to the PMD element such that the power is split equally between polarization components aligned to the slow and fast axes of the PMD element If the PMD setting is a continuous mode state or a lookup table state with an ID gt 255 the following error message will be displayed when the equal power split option is selected Active in DGD only Discrete ID 0 to 255 Document GP UM PMD 1000 21 Page 38 of 122 If the PMD setting is a lookup table state with index number between 0 and 255 when the equal power split option is selected the PMDPro will immediately adjust the SOP to balance the power split between the fast and slow axes and the following operation screen will be displayed EQU POW SPL DGD 43 20ps 0 0ps2 The lower line displays the current DGD setting on the left The SOPMD on the right will always be 0 0 for this option 2 OUTPUT DOP TO MIN This option can be used with any discrete or continuous mode PMD setting It tunes the polarization state at the input to the PMD element to the SOP that results in the maximum depolarization of the signal by the PMD element i e minimum DOP measured at the output polarimeter When this option is selected the following operation screen is displayed DOP I 100 O 30 19 90ps 300 0ps2 The top line shows the DOP measured by the input I and output O polarimeters and the bottom line shows the DGD and SOPMD of the currently
121. ptions and the ENTER key the center key in the arrow keypad to select the desired option 1 ITU FREQ CHANNEL Sets the operation wavelength Use the left and right arrow keys to move the cursor and the up and down arrow keys to increment the digits to select the desired ITU channel number range 1 87 for C band model The corresponding frequency and wavelength are displayed Ch C037 193 40THz 1550 12 nm Once the value is set pressing the ENTER key executes the setting and returns the display to the SETUP menu 2 GPIB ADDRESS This option sets the GPIB address for the PMDPro When this option is selected the screen displays GPIB ADDRESS 05 Range 01 to 30 Document GP UM PMD 1000 21 Page 13 of 122 Use the left and right arrow keys to move the cursor and the up and down arrow keys to increment the digits The range of available addresses is 1 to 30 and the default value is 5 Once the value is set pressing the ENTER key executes the setting and returns the display to the SETUP menu 3 GET DYNAMIC IP Sets the PMDPro for dynamic IP addressing and requests a dynamic IP address from the server If the instrument is able to establish communication with the DHCP server and successfully retrieve a dynamic IP address the dynamic IP address will be displayed on screen GETTING DYNAMIC IP Please Wait IP 191 168 0 65 Dynamic Mode Set i If the request is unsuccessful the address displayed will
122. r evaluation setup schematic For electrical compensation the compensator may be inside the receiver RX The plots shown in Figure 31 can be generated here with PMD compensation at different PMD settings of the PMD source PMD source PMD analyzer or monitor for link PMD determination The PMD values of fiber routes generally must be measured before link deployment This requires PMD analyzers In general a PMD analyzer requires a large bandwidth light source whether it is tunable laser based or broadband source based As mentioned previously the PMD of fiber routes may change with time due to changes in environmental conditions Fora ROADM network once the fibers are lit the wavelength channel for each transceiver pair is determined and is confined within a 50GHz bandwidth Therefore PMD analyzers requiring broadband light sources cannot be used to characterize such a system In addition it is undesirable to disconnect the transceivers and insert a PMD analyzer into the link because this would cause a severe service interruption It is therefore attractive to be able to determine the PMD value of an in service link while both the transmitter and receiver are operational This capability is important for the diagnosis of fiber routes with performance issues Document GP UM PMD 1000 21 Page 110 of 122 5 4 Desirable features for a PMD source High repeatability and rapid generation of 1 and higher order PMD values are desirable i
123. rameter values Sum of squares of Stokes values 1 00 String of characters too long gt buffer limit 0 Document GP UM PMD 1000 21 Page 100 of 122 Section 5 Applications This section includes brief descriptions of several application examples for a polarization optimized PMD source 5 1 PMD Tolerance Testing with Polarization Multiplexed Signals For polarization multiplexed signals the measured DOP at the input and output of the PMDPro are not accurate indicators of the PMD effect on the signal Therefore the functions that depend on them including the WSOP and PMDC functions should not be used with polarization multiplexed signals However the polarization controller s scrambling function can be used in conjunction with the basic PMD generation function to perform PMD tolerance testing with polarization multiplexed signals Front Panel Control 1 Set the PMD value Press the PMDE button to bring up the PMD generation menu Select either option 1 SET DISCRETE PMD or option 2 SET CONTINUOUS PMD 2 For discrete mode use the arrow buttons to select the index number corresponding to the desired DGD SOPMD pair The DGD SOPMD values will be updated in real time as the index numbers are changed SET PMD ID 1 0 36 ps 0 0 ps2 The continuous mode edit screen is shown below DGD _ 0 00 lt 91 04 SOPMD ___0 0 lt 0 0 For both DGD and SOPMD the number to the left of the lt symbol is the value
124. reen When the program is first started if the communication between the computer and PMDPro is properly established the screen shown below will be displayed If the program does not detect the PMDPro it will display a message to that effect Available communication ports will be displayed in a pull down menu at the bottom left of the screen Select Refresh if the correct port is not displayed The connection port can be verified from the Device Manager on the control computer Control Panel System Hardware Device Manager View Devices by Type Ports Document GP UM PMD 1000 21 Page 56 of 122 PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 OUTPUT POWER Pore aa PMDC DGD SOPMD Display the current DGD SOPMD setting Monitor DGD 30 13 Manual Advanced PMDE PMD Measurement Long Term PMD Monitor OUTPUT The program interface consists of a function selection panel on the left side of the screen and the main operation area which occupies most of the screen The function selection panel contains 13 buttons corresponding to various operation modes These buttons are divided into three groups The top group Front Panel Function includes most of the basic functions The second group Advanced Function includes more advanced functions using the quasi continuous PMD generation function and 2D and 3D graphing capabilities The third group
125. rent location type in the index number of the desired DGD SOPMD pair from the lookup table Index number range is 0 6560 For a discrete value this fully specifies the PMD The DGD and SOPMD fields do not have to be filled in For a continuous PMD state the PMD ID field does not have to be filled in DGD For a continuous PMD state type in the desired DGD in ps SOPMD For a continuous PMD state type in the desired SOPMD in ps Document GP UM PMD 1000 21 Page 89 of 122 When all of the PMD states to be stored have been entered in the table click the STORE button to store the PMD sequence to memory Note that for continuous states the state stored in memory and used for the scan is the closest matched set of calculated values to the user requested DGD SOPMD values PMD sequence recall To recall data from memory and display it on screen select the desired memory bank Then define the range of memory locations from which to recall data by selecting the start and end ID s in the corresponding boxes Click RECALL to display the data in the table on the right Export After stored data is recalled to the table on screen it can be exported to a text file by clicking the EXPORT button The program will prompt for a file name and location Data is stored in the format in which it is displayed in the on screen table nn gt File Edt Format View Help 182ps PMD 1000 182 ps ETA Dsc con 1 Serial Number 060 P
126. ribed in the previous section WDM WDM MUX Link with PMD DeMUX TCA 1000 Figure 26 System setup using TCA 1000 as signal emulator Figure 26 illustrates a system setup for PMD monitoring using General Photonics Tunable Channelized ASE Source TCA 1000 in conjunction with the PMDPro The TCA 1000 is used as the input to one frequency channel before multiplexing After demultiplexing that frequency channel is sent to the PMDPro which performs DGD measurements at user specified intervals Since the PMD effect varies with input polarization it is possible to obtain spurious results if the input polarization happens to be aligned to the effective fast or slow axis of the device or link under test To counter this possibility the TCA 1000 can be instructed to periodically rotate its output polarization state by 45 WDM WDM MUX Link with PMD DeMUX Tunable filter Figure 27 System setup for long term monitoring of in service link Document GP UM PMD 1000 21 Page 86 of 122 Figure 27 illustrates a system setup for monitoring the PMD of an in service link The signal is tapped before the demultiplexer sent through an EDFA and then the frequency channel to be tested is separated out with a tunable filter and sent to the PMDPro PMD 1000 182 ps Polarization Optimized PMD Source PMD Control Program Ver 2 0 Time Delay s 91 Frequency THz 9193 4 Wavelength nm 1550 12 Monitor Manual Start Time 7 06 PM 7 8 2010 File P
127. ription LCD display displays data and operation mode information Power power on off switch Input universal connector interface adapter for optical fiber input Output universal connector interface adapter for optical fiber output Keypad control button descriptions PMDE DGD PMD setting scan and emulation functions SOP Polarization control waveform and scrambling functions WSOP Automatic input polarization alignment for worst case PMD effect MONITOR Displays SOP and DOP readings from input and output polarimeters as well as output power and PMD information PMDC DGD and PMD compensation functions MANUAL SOP control via direct real time setting of individual polarization controller channel voltages STORE Allows user to store sequences of PMD values for scans or to store individual PMDC measurement results RECALL Allows user to recall stored PMD sequences or PMDC measurement results SETUP Allows user to set basic system parameters operation wavelength ITU channel GPIB address ESC Steps back to screen one level up from currently displayed screen ENTER center key in arrow keypad Enters parameters set with arrow keys A lt gt Arrow keys used to set measurement control parameters v Document GP UM PMD 1000 21 Page 9 of 122 eee 33595 8 GENERAL PHOTONICS CORP CHINO CA USA CE USB RS 232 ETHERNET BNC Figure 4 rear panel layout Rear panel description USB USB interface port RS 232 seria
128. rotators which can rotate SOP in 3 ways When the rotator between two adjacent crystals rotates the SOP 45 the optical axes of the two crystals are aligned to produce the maximum combined DGD When the rotator between two adjacent crystals rotates the SOP 45 the optical axes of the two crystals are counter aligned to produce the minimum combined DGD When the rotator between two adjacent crystals rotates the SOP 0 no rotation the optical axes of the two crystals Document GP UM PMD 1000 21 Page 112 of 122 are aligned 45 from each other producing higher order PMD This higher order PMD generation capability is not available in previous DGD generator designs in which the polarization rotators can only generate 45 polarization rotations The 0 degree polarization rotation is essential for the generation of higher order PMD The total number of PMD values that can be generated with N 1 sections of birefringent material and N rotator pairs is 3 For N 8 the total number of PMD states is 6561 The total number of DGD only 1 order PMD states is 2 For N 8 the total number of DGD only states is 256 Unlike the analog crystal rotators used in other PMD source designs which suffer from slow speed and low repeatability the digital ternary operation method of this PMD source makes PMD generation fast and highly repeatable In addition to the digital ternary rotators described above the PMDPro uses a quasi continuous
129. rows to move between scan setup options and the ENTER key to access the setup screen for the selected option a START This option starts the scan Use the other options to perform the scan setup then return to option a to begin the scan When the scan is running the screen displays DGD ID 000 CY 0000 DGD 0 00 ps ID 000 For a DGD only scan or PMD ID 0000 CY 0000 0 00 ps 0 0 ps2 For a discrete PMD scan During the scan the screen displays the current ID DGD and if applicable SOPMD values and the number of completed cycles b MODE There are two scan options Discrete PMD and DGD Only Use the up and down arrows to toggle between them and ENTER to select the displayed option Discrete PMD scans through all 6561 PMD states in the lookup table from lowest index number to highest index number DGD Only scans through a selected subset of the 256 DGD states with SOPMD 0 in order of increasing DGD If DGD Only is selected option a becomes START Scan DGD and option e is enabled c INTERVAL This option allows the user to set the dwell time in ms at each point in the scan The time range is 1 60 000 ms Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit The ENTER key sets the dwell time to the displayed value d CYCLES This option sets the number of times to run the scan The cycle range is 1 9999 Use the l
130. selected PMD state The polarization controller will actively optimize SOP as long as the PMDPro is in this mode 4 2 6 PMDC Pressing the PMDC button accesses the PMDPro s PMD compensation functions In this mode the PMDPro uses its polarization controller and PMD generation element to find the optimum SOP and PMD value to compensate for any PMD in the input signal This set of operations uses only the PMDPro s discrete PMD generation mode Additional PMDC based functions are available in the deluxe version of the control software For the PMDC functions the PMDPro tunes the SOP and DGD PMD to maximize the DOP measured by the output polarimeter The combinations of SOP and DGD or PMD that are available for the search depend on the function chosen by the user The DGD and PMD optimized compensation functions can also be used to measure the DGD or PMD in the system Data from any of the 4 PMD compensation modes can be stored using the STORE button for more detail see the STORE section When PMDC is selected the screen displays the following options Document GP UM PMD 1000 21 Page 39 of 122 1 DGD OPTIMIZED Comp 2 PMD OPTIMIZED Comp 3 DGD SELECTED Comp f 4 PMD SELECTED Comp Use the up and down arrow keys to move between menu options and the ENTER key the center key in the arrow keypad to select the desired option 1 DGD OPTIMIZED COMP This function scans through all available DGD states with SOPMD 0 and
131. set by the user The number on the right is the maximum available value The maximum available DGD value is determined by whether the PMDPro is a 90 ps or 180 ps unit The maximum available SOPMD value is determined by the DGD value the user selects As the user changes the requested DGD value the maximum available SOPMD value will change accordingly Document GP UM PMD 1000 21 Page 101 of 122 90ps PMDPro Maximum SOPMD determined by selected DGD N w amp O oO O a DGD ps Selected DGD Figure 28 DGD SOPMD range determinants for continuous control Use the left and right arrow keys to move the cursor and the up and down arrow keys to increment the digits to set the DGD and SOPMD values to be matched Note that the left and right arrow keys will scroll through all modifiable cursor positions For example pressing the right arrow key from the rightmost digit of the DGD setting line will move the cursor to the leftmost position of the SOPMD setting line When the DGD and SOPMD values are set press the ENTER key to calculate the closest available matches to the requested values If the requested SOPMD is out of range the PMDPro will flash an SOPMD out of range error message before returning to the PMD selection screen If the selected values are within range the LCD will display DGD 31 04 C 31 10 SOPMD _ 530 0 C 530 0 where the number to the right of the C on each line is now the calculated
132. set up the static Ethernet configuration Static IP setup cannot be done from the front panel Document GP UM PMD 1000 21 Page 51 of 122 4 GP_SET ETHERNET program To run this program a Connect the PMDPro to the control computer with a straight wired RS 232 b c The program has 3 tabs cable as described in section 4 3 3 This program is RS 232 only and cannot be run from any other interface Set the control computer s baud rate to 28800 Open the program GP_SET ETHERNET Select the correct serial RS 232 port from the port configuration box at the top of the screen The baud rate should be set to 28800 Once these two parameters are set click the white arrow to run the program The first tab GET IP CONFIG is used to query the current IP configuration of the instrument When the Get IP Config button at the left of the screen is clicked the program will read back the instrument s current network parameters as well as whether the instrument is currently set for static or dynamic IP addressing GP_SET_ETHERNET vi gt Ranaral Dhataniere 2 GP ETHERNET SETUP Sitti tai tf HULUN Serial Port Baud Rate Port Configuration coma 28800 Note RS 232 baud rate must be 28800bps GET IP CONFIG MODE SETTING STATIC IP SETTING Click the button to get IPCONFIG z IP Address 192 168 1 250 Get IP Config ETHERNET MODE Net MASK 255 255 255 0 STATIC Gate
133. sweep out close to a full ring while the last two sweep out about half a ring Fes Figure 10 Sine wave with A 60V f 5Hz on channel 1 Figure 11 Sine wave with A 60V f 5Hz on channel 2 Figure 12 Sine wave with A 30V f 5Hz on channel 3 Figure 13 Sine wave with A 30V f 5Hz on channel 4 Document GP UM PMD 1000 21 Page 34 of 122 A triangle wave applied to a single channel also sweeps out a ring or portion thereof depending on the amplitude on the Poincar sphere but the polarization change along that path occurs at a constant speed determined by the frequency The final trace over several periods will look the same as that of a sine wave If a square wave is applied to a single channel the polarization will switch periodically between two polarization states determined by the amplitude of the wave The frequency determines how long the polarization stays in each state Figure 14 17 show the traces for a square wave with amplitude 30V and frequency 5 Hz applied to channels 1 4 respectively Figure 14 Square wave with A 30V f 5Hz on channel 1 Figure 15 Square wave with A 30V f 5Hz on channel 2 Figure 16 Square wave with A 30V f 5Hz on channel 3 Figure 17 Square wave with A 30V f 5Hz on channel 4 Document GP UM PMD 1000 21 Page 35 of 122 If periodic waveforms are simultaneously applied to more than one channel their effects are superposed and the polarization state periodically sweeps out a more complicat
134. t is the same for all communication interfaces RS 232 USB Ethernet or GPIB Once the connection has been established and the instrument has been detected by the control computer any program that supports the communication protocol being used RS 232 USB Ethernet or GPIB can be used to send ASCH commands to the instrument Commands should be sent one at a time A new command should not be sent until the instrument s response to the preceding command is received Table 1 PMD 1000 Communication Command List Command Description Response IDN Query product number GP PMD Pro V2 0 VER Query firmware version V1 3 1 110423A G 8 Bit Ana 09 1 ps SER Query product serial number Example 106800000040 PMDE MODE Single Value Control ea a e e a aa e e PMD idn Discrete mode PMD control E00 if successful See Table 2 for Set DGD SOPMD to values corresponding to index other error code definitions number idn This command does not change the operation mode or update the LCD display PMD Discrete mode PMD query Example 1005 Query current or most recently set PMD ID If not in PMD mode will return the last Range 0 to 6560 PMD ID set PMD CON CAL Continuous mode PMD query dgd sopmd Query most recent set of calculated DGD SOPMD Eg 30 37 100 0 values DGD given in ps SOPMD in ps PMD CON MAX Continuous mode PMD query dgd max sopmd max Queries 1 DGD range of PM
135. th components of the signal and Eq 1 may no longer hold Nevertheless there always exists an input SOP at which the PMD has its most severe impact on the quality of the signal and at which the DOP of the signal at the output end is therefore at a minimum There also exists an input SOP at which the PMD has the least effect on the quality of the signal and at which the output DOP may therefore be much higher Document GP UM PMD 1000 21 Page 109 of 122 PMD source for PMD compensator evaluation A PMD source is also necessary to evaluate the performance of a PMD compensator whether optical or electrical as shown in Figure 32 PMD compensator evaluation can include several types of tests First the system improvement margin at different PMD settings can be determined Second the PMD compensation range of the compensator can be determined by gradually increasing the input PMD while measuring the BER of the fiber link 3 Third the PMD compensator s PMD recovery time can be determined by performing a step PMD change and monitoring the PMD compensator s response Finally the PMD compensator s SOP recovery time at different PMD settings can be determined by changing the SOP rapidly at each PMD setting and monitoring the PMD compensator s response Therefore a PMD source with fast PMD variation and fast polarization control capabilities is attractive for PMD compensator evaluation PMD Compensator Figure 32 PMD compensato
136. the lower right of the screen during operation Use the arrow keys to stop operation and return to waveform setup 4 2 5 WSOP After a static PMD state has been set using the PMDE function either from discrete or continuous mode this function uses the PMDPro s polarization controller to adjust the input SOP to the PMD generation element to obtain the worst case PMD effect based on either of two methods In the first case the input polarimeter reading is used to control the polarization controller to align the input polarization state to achieve an equal power split between polarization components aligned to the slow and fast axes of the PMD element as shown in the figure below Document GP UM PMD 1000 21 Page 37 of 122 Figure 22 Effect of input polarization alignment on PMD effect caused by a DGD element a Equal power split between fast and slow axes b Input polarization aligned to fast axis pulse is not distorted c Input polarization aligned to slow axis pulse is phase delayed but not distorted In the second case the output polarimeter reading is used to control the polarization controller to tune the input polarization state to minimize the DOP of the signal after it passes through the PMD element When WSOP is selected the screen displays 2 options 1 EQUAL POWER SPLIT 2 OUTPUT DOP TO MIN 1 EQUAL POWER SPLIT This option can be used with a DGD only SOPMD 0 discrete mode state PMD ID 0 255 It aligns the
137. tore Recall PMD Calculation Exit F9 and y ASRLAANSTE m Command Press Sen ommand to PMID 100 Response Ee Cc ET oe 4 Select a frequency in the triangle scrambling section at the top left of the screen and click the Start button to begin scrambling Document GP UM PMD 1000 21 Page 104 of 122 Quasi continuous PMD setting 1 Click the Advanced PMDE button on the left function panel to bring up the advanced function PMDE interface 2 Click the Continuous PMD Polarization Control tab PMD 1000 182 ps Polarization Optimized PMD Source Serial Number 060 PMD Control Program Ver 2 0 Continuous PMD Polarization Control Scan Stored PMD PMD Emulation PMD Scan SOP PMDC Monitor Manual Advanced PMDE PMD Measurement Long Term PMD Monitor Setup Store Recall PMD Calculation Exit T9 Comar kl ASRL4 INSTR p 3 Set the DGD and SOPMD values by dragging the sliders by entering the desired values in the value selection boxes under the plot axes and then clicking the mouse outside the text boxes or by dragging the red cursor within the plot area Click the Set button on the right of the screen to set the DGD SOPMD values The DGD and SOPMD indicator boxes on the right of the screen will display the closest available values to those selected 4 Select the continuous SOP scrambling frequency by either selecting a value from the pull down menu or typing a value in the box un
138. uld be set to English United States Changing the language settings can cause the program to read numerical values incorrectly Document GP UM PMD 1000 21 Page 116 of 122 Section 7 Technical Support General Photonics is committed to high quality standards and customer satisfaction For any questions regarding the quality and use of the PMDPro or future suggestions please contact General Photonics Corporation at 909 590 5473 telephone or 909 902 5536 fax or by e mail at support generalphotonics com General Photonics will respond to all customer questions within 24 hours during regular business hours General Photonics can also be contacted by mail at General Photonics 5228 Edison Avenue Chino California 91710 USA Document GP UM PMD 1000 21 Page 117 of 122 Appendix A ITU Grid Channel Lookup Table The following tables are references for the PMDPro operation wavelength setup They list the frequency and wavelength corresponding to each channel in the C and L bands C BAND CHANNEL FREQUENCY GHz WAVELENGTH nm C1 191600 1564 68 C2 191650 1564 27 C3 191700 1563 86 C4 191750 1563 45 C5 191800 1563 05 C6 191850 1562 64 C7 191900 1562 23 c8 191950 1561 83 c9 192000 1561 42 C10 192050 1561 01 C11 192100 1560 61 C12 192150 1560 20 C13 192200 1559 79 C14 192250 1559 39 C15
139. umns DGD SOPMD and DOP Document GP UM PMD 1000 21 Page 81 of 122 Scan SOPMD only This function scans through a user defined SOPMD range with a fixed DGD value PMD 1000 182 ps Polarization Optimized PMD Source PMD Control Program Ver 2 0 PMD Measurement DGD Measurement Scan Setting x n Instantaneous OGD ps Instantaneous SOPMO ps2 Output DOP Ps BS 335 4931 sopmD DOP Monitor Manual _Foxed DGD PEJ Start SOPMD Advanced PMDE Jo PMD Measurement Stop SOPMD J so Long Term PMD Monitor SOPMO Step jx O 320 1000 1500 2000 2500 3000 3500 4000 4500 5000 Store Recall T5 ee E ooon Mar DOP ba 473 PMD Calculation Exit F9 J ASRL4 INSTR a ie eee Selection parameters Fixed DGD fixed DGD value in ps Start SOPMD SOPMD start value in ps Stop SOPMD SOPMD end value in ps SOPMD step SOPMD step size in ps Scan Interval on top of graph dwell time per point in s Minimum value 0 4 s When the scan parameters are set click Start to start the scan At each point in the scan the DGD SOPMD and maximum output DOP for that point are displayed above the graphs and the maximum output DOP vs SOPMD is plotted in the graph on the left The maximum output DOP for the scan and the corresponding DGD and SOPMD values are displayed below the graph After the scan is finished the data can be saved to a file by clicking SAVE DATA Data
140. us DGD ps Instantaneous SOPMDXps2 Output DOP PMDC Ja u7 Stop OGD TY Monitor BE 2 DOP DGD SOPMD SOP OGD step Manual OF Start SOPMD 9200 Advanced PMDE Stop SOPMD 3 SMSA PMD Measurement SOPMD Step Long Term PMD Monitor 0 RE TR E A Setup 60 62 64 66 68 70 72 74 76 78 80 82 84 85 88 90 DGD Store Recall PMD Calculation Exit F9 ASRLAINSTR Command Press Send ans mand to PMID 1000 Response i ee ie U Selection parameters Start DGD DGD start value in ps Stop DGD DGD end value in ps DGD step DGD step size in ps Start SOPMD SOPMD start value in ps Stop SOPMD SOPMD end value in ps SOPMD step SOPMD step size in ps Scan Interval on top of graph dwell time per point in s Minimum value 0 4 s When the scan parameters are set click Start to start the scan As each point is generated the DGD SOPMD and output DOP are displayed above the graphs and the output DOP vs DGD is plotted in the graph on the left The data is also plotted in a 3D graph on the right of the screen The graph can be rotated or zoomed to view the data from different perspectives Document GP UM PMD 1000 21 Page 78 of 122 To rotate a 3D graph drag it with the mouse To zoom in or out hover the mouse over it and scroll up or down After the scan is finished the data can be saved to a file by clicking SAVE DATA Data is saved as a text file with 3 co
141. us mode d 180 ps version quasi continuous mode Pressing the PMDE key on the front panel accesses the PMDPro s DGD PMD generation functions including generation of a single DGD SOPMD pair scanning through DGD or PMD states in the lookup table generating a continuous PMD trace scanning through a user generated sequence of states or generation of a Maxwellian distribution of DGD values Document GP UM PMD 1000 21 Page 16 of 122 When the PMDE key is pressed the LCD displays 6 menu options on 3 screens 1 SET DISCRETE PMD 2 SET CONTINUOUS PMD 3 SCAN DISCRETE PMD f 4 PMD TRACE SCAN l 5 DGD PMD EMULATION 6 SCAN PMD MEM BANK Use the up and down arrow keys to move between menu options and the ENTER key the center key in the arrow keypad to select the desired option 1 SET DISCRETE PMD Set a single PMD value first and second order PMD combination using the lookup table When this option is selected the LCD displays the following screen SETPMD ID ___0 0 00 ps 0 0 ps2 Use the left and right arrow keys to move the cursor and the up and down arrow keys to increment the digits to select the index number ID corresponding to the desired PMD value There are 6561 PMD values index numbers 0 to 6560 PMD values are grouped in the following order states with DGD only states with wavelength independent SOPMD states with wavelength dependent SOPMD The PMD corresponding to the selected index is displayed i
142. uses the PMD generator to have the worst case total PMD effect on the optical signal and is therefore the optimal polarization state for total PMD tolerance tests of Document GP UM PMD 1000 21 Page 111 of 122 transceivers and fiber systems Finally the optimized input SOP obtained by maximizing the DOP from the second polarimeter enables PMD compensation PC Polarimeter 1 PMD Generator Polarimeter 2 E Output DSP based circuit Interfacing electronics Input Figure 33 System diagram of polarization optimized PMD source The DSP based circuit is used to 1 process information from the polarimeters and control instructions from users 2 instruct the PMD generator to select desired PMD values 3 control the PC to optimize the input SOP for various functions The PMD generator used in the PMDPro is based on General Photonics patent pending ternary polarization rotation technology The generator is constructed using a series of birefrigent crystals with a ternary polarization rotator sandwiched between each pair of adjacent crystal segments as shown in Figure 34 The crystals are arranged in descending order with lengths decreasing sequentially by a factor of 2 Each rotator is capable of rotating the state of polarization SOP by 45 0 or 45 degrees ee Rotator 1 Rotator 2 Rotator N Birefringent Crystals Figure 34 The construction of a PMD generator made with birefringent crystals and ternary polarization
143. vanced functions The structure features and functions of the PMDPro are described in more detail in sections 3 and 4 Section 5 includes application examples and section 6 describes basic troubleshooting Document GP UM PMD 1000 21 Page 6 of 122 Section 3 Feature Description 3 1 Optical Features The PMDPro system has two bulkhead adapters on the front panel to accommodate the optical input and output The adapters are universal connector interfaces UCI which feature a male type adapter top piece that can be removed for direct access to the ferrule end for routine cleaning and maintenance without removing the entire adapter from the panel This feature helps avoid high insertion loss high return loss and measurement instability caused by dirty or contaminated connectors In addition the PMDPro s universal interchangeable adapter allows the end user to switch to ST SC or FC connectors without opening the instrument panel Although the PMDPro is shipped with a standard typically FC PC or FC APC fiber adapter other interchangeable inserts are available For additional information on different input fiber adapter inserts please contact General Photonics External fiber connectors should be cleaned using industry standard cleaning methods before connection to the PMDPro If this procedure is followed before each connection the instrument s internal connector ferrules should not need regular cleaning However high insertion l

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