Faraday Isolator - Newport Corporation
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1. various claims regarding the potential harmful and beneficial effects of magnetic fields on humans it is prudent to limit interaction with these fields as much as possible Personnel with any magnetically sensitive implants such as pacemakers should consult their medical doctor regarding any potential complications which could arise from the isolator external magnetic fields Other non health related hazards The Faraday Isolator external magnetic fields can draw ferromagnetic objects into the magnet housing that can damage the optical elements within the device Keep a suitable area in all directions around the Faraday Isolator clear of any loose ferromagnetic objects Ideally use non magnetic tools such as 300 series stainless steel or titanium and hardware to secure the Faraday Isolator If only ferromagnetic tools are available use extreme care when using them around the Faraday Isolator It is always helpful to bring such tools towards an aperture or end radially rather than along the optical beam path Doing this ensures that the fields will tend to pull such objects into the magnet housing endplate rather than into the optical aperture Where possible use two hands one to hold the tool and the other to guide it to the desired destination 1 3 1 3 1 Another concern regarding external magnetic fields is their effect on magnetically sensitive devices The external fields are strong enough to induce a pulse of current in elec2. Faraday Isolator Broad Band ISO Series User s Manual AD NNevvport Experience Solutions Preface Warranty Newport Corporation warrants that this product will be free from defects in material and workmanship and will comply with Newport s published specifications at the time of sale for a period of one year from date of shipment If found to be defective during the warranty period the product will either be repaired or replaced at Newport s option To exercise this warranty write or call your local Newport office or representative or contact Newport headquarters in Irvine California You will be given prompt assistance and return instructions Send the product freight prepaid to the indicated service facility Repairs will be made and the instrument returned freight prepaid Repaired products are warranted for the remainder of the original warranty period or 90 days whichever is longer Limitation of Warranty The above warranties do not apply to products which have been repaired or modified without Newport s written approval or products subjected to unusual physical thermal or electrical stress improper installation misuse abuse accident or negligence in use storage transportation or handling This warranty also does not apply to fuses batteries or damage from battery leakage THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR F
3. ITNESS FOR A PARTICULAR USE NEWPORT CORPORATION SHALL NOT BE LIABLE FOR ANY INDIRECT SPECIAL OR CONSEQUENTIAL DAMAGES RESULTING FROM THE PURCHASE OR USE OF ITS PRODUCTS First printing 2005 2005 by Newport Corporation Irvine CA All rights reserved No part of this manual may be reproduced or copied without the prior written approval of Newport Corporation This manual has been provided for information only and product specifications are subject to change without notice Any change will be reflected in future printings Newport Corporation 179 Deere Avenue Irvine CA 92606 USA P N 90025451 Rev A Preface iii Technical Support Contacts North America amp Asia Europe Newport Corporation Service Dept Newport MICRO CONTROLE S A 1791 Deere Ave Irvine CA 92606 Zone Industrielle Telephone 949 253 1694 45340 Beaune la Rolande FRANCE Telephone 800 222 6440 x31694 Telephone 33 02 38 40 51 56 Asia Newport Opto Electronics Technologies 253 Aidu Road Bid 3 Fir 3 Sec C Shanghai 200131 China Telephone 86 21 5046 2300 Fax 86 21 5046 2323 Newport Corporation Calling Procedure If there are any defects in material or workmanship or a failure to meet specifications promptly notify Newport s Returns Department by calling 1 800 222 6440 or by visiting our website at www newport com returns within the warranty period to obtain a Return Material Authorization Number RMA Return the product to Newport C
4. e the plane of polarized light please view our Application Notes available through the Support tab Dispersion Some pulse broadening does occur when using Newport s broadband isolator Use the following Sellmeier Equation E E E he 1p n l where E 9 223eV and E 25 208eV Operating and Storage Temperature Performance of Newport s broadband rotators isolators is related to operating temperature 2 Factory Service Information 2 1 Service Form CN Newport Corporation U S A Office 800 222 6440 FAX 949 253 1479 Nevvport Name Return Authorization Please obtain RA prior to return of item Company Address Date Country Phone Number P O Number FAX Number Item s Being Returned Model Serial Description Reason for return of goods please list any specific problems 10 Notes Newport Corporation Worldwide Headquarters 1791 Deere Avenue Irvine CA 92606 In U S 800 222 6440 Tel 949 863 3144 Fax 949 253 1680 Internet sales newport com GO Newport Visit Newport Online at www newport com BSI JA Newport Corporation Irvine California has been certified compliant with ISO 9001 by the British Standards Institution ISO 9001 FM 27207 Printed in the U S
5. er Covers will need to be removed so that the Escape Ports allow rejected polarization light to be safely dumped onto a beam dump Failure to allow these rejected polarizations to escape can cause the device to heat up Such heat can degrade the performance of the Faraday Isolator or in severe cases cause damage to optical components in the isolator While working with low alignment level power and wearing safety glasses remove the screw holding the dust cover in place for both the input and output Any rejected polarized beams in either the forward or backward propagating directions can now exit the polarizer assembly Use an IR viewer or IR card to locate these beams Ensure that they are terminated on beam dumps consistent with the maximum amount of power that may be in such beams If the Faraday Isolator is used in applications where strong reflections and or optical gain elements amplifiers exist there may be very high power rejected beams for backward N General Information 1 3 3 1 4 Notes propagating light at the input polarizer If the average power levels used do not exceed 25W transmitted or 0 5W of backward propagating power then the Polarizer Covers may be kept in their factory positioned orientation that it with all rejected beams blocked by the Polarizer Cover However if the Faraday Isolator is to be used with very high peak intensities it is prudent to allow rejected beams to escape on to external beam dumps to p
6. fety guidelines which limit external fields from magnetic devices to be less than 2KGauss at a radial distance of 5cm from the outside of the device However such fields can be sufficient to attract nearby objects such as knives and razor blades Should attraction of such objects begin to occur there would be a strong attractive force directing these objects towards the interior of the magnet housing This could be particularly likely to result in injury e g a cut or puncture wound if such attraction occurred while the device was being handled particularly if a body part of the operating personnel is near a beam Aperture i e end of the device To minimize the above risks remove all loose ferromagnetic objects from the path over which your Newport Faraday Isolator is to be moved prior to attempting to move it Do not pick up the isolator by its ends i e apertures where the attractive magnetic fields are strongest Always pick the isolator up along its sides Reflection of rejected beams from the input and output polarizer The polarizer covers have been positioned at the factory to block all beams rejected from the polarizers In the event that your Faraday Isolator will be used with transmitted average powers in excess of 25W or will block backward propagating light in excess of 0 5W average power these polarizer covers must be removed to allow rejected beams to exit see Figure 1 onto user supplied beam dumps These rejected beams ca
7. mation However the beam is shifted vertically rather than horizontally This can be seen in figure 2 A more detailed illustration of the aperture locations is in figure 4 Figure 3 Input View of 5mm Aperture Broadband Faraday Isolator Figure 4 shows a diagram with multiple views of the 5mm aperture broadband Faraday isolator Figure 4 Diagram View of 5mm Aperture Broadband Isolator NOTE vim T d POLARIZERS NOT SHOWN E nan oda IN TOP VIEW 1 3 2 Using your Faraday Isolator Observe the guidelines for safe use of your Faraday Isolator found in Section 1 2 above when removing your isolator from its shipping container Do not remove the protective dust cover endcaps from the polarizers until the device is in a clean relatively dust free environment Save the protective endcaps packaging material and containers in the event that the device should ever need to be returned to Newport Verify that the Input and Output polarization states are consistent with the intended mode of operation If not re adjust the isolator as required see Section 1 3 3 With the source laser off or running at very low power less than 100mW position the Faraday Isolator such that the source laser beam can be directed through the Input Aperture Critical alignment of the Faraday Isolator should be done at low power less than 100mW in order to prevent optical damage to your isolator or laser source Use IR cards or viewers to ensure tha
8. n represent a hazard to users and or their General Information 3 colleagues Care must be exercised to ensure that all rejected beams both transmission and isolation directions are accounted for and terminated into functional beam dumps Wherever possible keep the strongest rejected beams in the horizontal plane of the table or otherwise safest direction typically down into the table Always wear laser safety glasses goggles consistent with all laser frequencies and power levels present See the following sections for further details Failure of operating personnel to observe standard laser safety by sighting down through the isolator when laser radiation is present The optical elements within the Newport Faraday Isolators can be transmissive throughout the visible and near infrared Consequently it is never appropriate to view through the device in either the transmission or isolation direction when laser radiation is present even with laser safety goggles Never sight through your Newport Faraday Isolator in either direction when there is any possibility of laser radiation being present Harm caused by external magnetic fields Your Newport Faraday Isolator has been designed to meet existing Federal safety guidelines for external fields as noted previously Such guidelines could change in the future as more information becomes known or reviewed regarding the interaction between magnetic fields and human health Since there exist
9. orporation freight prepaid clearly marked with the RMA and we will either repair or replace it at our discretion Newport is not responsible for damage occurring in transit and is not obligated to accept products returned without an RMA E mail rma service newport com When calling Newport Corporation please provide the customer care representative with the following information Your Contact Information Serial number or original order number Description of problem 1 e hardware or software To help our Technical Support Representatives diagnose your problem please note the following conditions Is the system used for manufacturing or research and development What was the state of the system right before the problem Have you seen this problem before If so how often Canthe system continue to operate with this problem Or is the system non operational e Can you identify anything that was different before this problem occurred Preface Table of Contents M atrantvcs cat alte cat oca oup ed R edes ii Technical Support Contacts esser tee Serb e Ind a ure bei ad bad erue qes iii Table OP Contents daba eco RERO auntie css Raa E AA iv 1 General Information 1 l t Introd ctio a5 crt ones NOS A Sabe teo 1 1 2 Safe Use of Your Newport Faraday Isolator 2 3 AOSTA OI au etes a cim etico eis a s eter br eds Lb mr toes oo 4 1 3 1 The Newport Broadband Faraday I
10. revent any ablation damage to the Nickel plated Polarizer Covers Follow the same procedure above as for high average powers in order to safely terminate all rejected beams Tuning your Faraday Isolator For the 5mm aperture ISO 05 800 BB there are only two configurations for the input polarization In order to switch between the two the input and output polarizer dust covers must be removed then the polarizer mounts must be removed and rotated 90 deg Caution must be taken during this operation to avoid attraction of a screwdriver to the aperture of the device and the potential damage to the optics For more details please contact Newport s technical sales department at tech newport com Specifications Mod soosswseo _ 180 05 800 88 P Clear Aperture mm Canter Wavelength om m w Spectral Range nm 720 950 720 950 800 Isolation dB 25 C 230 288 800 o m m om w Pulse Damage Threshold MW cm For a 10 ns pulse Polarizer Type Glan Laser Calcite PBS Cube Rotating Medium Terbium Gallium Granet Terbium Gallium Granet 1 Polarization Orientation Please note that the broadband rotators and isolators utilize a 45 crystal quartz rotator At the center wavelength there will be 90 polarization rotation in the forward direction In the reverse direction there will be x 0 polarization rotation across the entire spectral bandwidth of the device For more information on how our Broadband isolators rotat
11. solator 4 1 3 2 Using your Faraday Isolator eese 5 1 3 3 Tuning your Faraday Isolator ssssssss 7 TA Specifications eate evertere eoe meer te eroe aces zr ie Nen es via 7 2 Factory Service Information 9 2 4 Service iF OFM exes egestas iat bales de da decere eee eai de eee eo ead 9 1 1 General Information Introduction Newport s ISO 05 800BB Faraday Isolator is essentially a uni directional light valve or spectrally selective one way mirror It is used to protect a laser source from destabilizing feedback or actual damage from back reflected light Figure 1 below identifies the main elements of your Faraday Isolator Figure 1 ISO 05 800BB Broadband 5mm Aperture Faraday Isolator Transmission Arrows Magnet Polarizer Cover Housing Output Input Polarizer Polarizer Mount l Mount Base plate The 5mm aperture Faraday isolator is a rectangular shaped magneto optic device Strong Neodymium Iron Boron permanent magnets are used to generate high gt 10 000 Gauss axially oriented fields within the magnet housing The strong longitudinal field causes 45 degrees of non reciprocal polarization rotation for propagating light via the Faraday Effect in the Terbium Gallium Garnet TGG crystal located within the magnet housing Following the TGG crystal is a quartz reciprocal rotator with 45 deg rotation In the forward direction the two rotations add
12. t the source laser beam is centered on the input and output apertures The clear aperture of this device is 4mm centered on the circular cross section of the magnet body There are different mounting options for establishing appropriate beam height It is also preferable to use an IR viewer to ensure that weak reflections from AR coated optical surfaces in the Faraday Isolator are not being directed back into the source laser The optical surfaces in the Faraday Isolator are angled slightly to reduce these reflections Increasing the distance between the Faraday Isolator and the source laser can also help ensure that no reflections couple back into the source laser if necessary Alternatively if the beam used is smaller than the aperture of the device by a reasonable margin the device may be slightly tilted At this point the Faraday Isolator should be secured to the work surface with two to four 4 20 or M6 screws one for each slot in the baseplate flanges Steel ferromagnetic ball drivers or other such wrenches will be attracted to the external magnetic field surrounding the device If possible use anti magnetic stainless steel or titanium tools If ferromagnetic tools are used it is desirable to introduce the slowly towards the device from the sides along the direction of the baseplate flange slots If the Faraday Isolator will be used with average powers in excess of 25W transmitted or 0 5W rejected backward propagating radiation the Polariz
13. tronic devices such as digital watches that can destroy them The fields can also disrupt the operation of other mechanical devices with ferromagnetic parts in them Finally the external fields can erase information from magnetic strips such as are found on credit and ID cards Remove all magnetically sensitive materials and devices such as watches computer hard drives and magnetic strips from operators prior to working in the proximity of an isolator Operation The Newport Broadband Faraday Isolator Figure 2 View of ISO 05 800 BB with polarizer covers removed Polarizer Cover Screw Holes N Input Polarizer With the polarizer covers off a polarizer can be seen at each end of the device For the 5mm aperture devices glan laser calcite polarizers are used The arrow stickers on the top indicate the transmission direction The input polarization shown is horizontal The central magnet housing together with the TGG and quartz crystals residing in its center form a broadband Faraday rotator The input and output polarizers work in conjunction with the central Faraday rotator to form a Faraday Isolator as described previously in Section I Figures 3 shows the input view of the isolator note that the aperture is displaced to one side This is due to the displacement of the beam after transmission through the glan laser calcite input polarizer The output polarizer creates a similar magnitude of displacement General Infor
14. up resulting in 90 deg of rotation In the reverse direction the two rotations are opposite and result in 0 deg of rotation The change in rotation as the wavelength shifts from the central wavelength is similar for both 1 2 TGG and quartz resulting in broadband operation In operation the magnet housing is sandwiched between input and output polarizers that have their transmission axis oriented 90 degrees relative to each other In the reverse direction the backward traveling beam has a polarization orthogonal to the input polarizer and is therefore crossed with it resulting in a rejected beam exiting the input polarizer Safe Use of Your Newport Faraday Isolator The operational hazards presented to operating personnel by the use of your Newport Faraday Isolator are listed below An explanation of how the Faraday Isolator is designed together with procedures users can employ to eliminate or minimize these hazards is presented in italics l Danger of sharp ferromagnetic objects being attracted to the residual permanent magnet fields outside of the isolator This hazard is of most concern if such fields cause flying objects when being handled Your Newport Faraday Isolator requires strong internal magnetic fields to operate properly Efforts have been made to minimize external fields from the device while still maintaining a relatively small and cost effective package The external fields are designed to be well within Federal sa
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