IEC 61 290 1 1 Edition 3 0 201 5 05 INTERNATIONAL STANDARD Optical amplifiers – Test methods – Part 1 1 Power and gain parameters – Optical spectrum analyzer method IE C 6 1 2 9 0 1 1 2 0 1 5 0 5 (e n[.]
I E C 61 90-1 -1 ® Edition 3.0 201 5-05 I N TE R N ATI ON AL STAN DAR D Opti cal am pl i fi ers – Test m eth o d s – IEC 61 290-1 -1 :201 5-05(en) Part -1 : Power an d g n param eters – Opti cal spectru m an al yzer m eth od TH I S P U B L I C AT I O N I S C O P Y R I G H T P R O T E C T E D C o p yri g h t © I E C , G e n e v a , S w i t z e rl a n d All rights reserved Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or IEC's member National Committee in the country of the requester If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or your local IEC member National Committee for further information IEC Central Office 3, rue de Varembé CH-1 21 Geneva 20 Switzerland Tel.: +41 22 91 02 1 Fax: +41 22 91 03 00 info@iec.ch www.iec.ch Ab o u t th e I E C The International Electrotechnical Commission (I EC) is the leading global organization that prepares and publishes International Standards for all electrical, electronic and related technologies Ab o u t I E C p u b l i ca t i o n s The technical content of IEC publications is kept under constant review by the IEC Please make sure that you have the latest edition, a corrigenda or an amendment might have been published I E C Catal o g u e - websto re i ec ch /catal o g u e The stand-alone application for consulting the entire bibliographical information on IEC International Standards, Technical Specifications, Technical Reports and other documents Available for PC, Mac OS, Android Tablets and iPad I E C pu bl i cati on s search - www i ec ch /search pu b The advanced search enables to find IEC publications by a variety of criteria (reference number, text, technical committee,…) It also gives information on projects, replaced and withdrawn publications E l ectroped i a - www el ectro ped i a o rg The world's leading online dictionary of electronic and electrical terms containing more than 30 000 terms and definitions in English and French, with equivalent terms in additional languages Also known as the International Electrotechnical Vocabulary (IEV) online I E C G l o ssary - std i ec ch /g l o ssary More than 60 000 electrotechnical terminology entries in English and French extracted from the Terms and Definitions clause of IEC publications issued since 2002 Some entries have been collected from earlier publications of IEC TC 37, 77, 86 and CISPR I E C J u st Pu bl i sh ed - websto re i ec ch /j u stpu bl i sh ed Stay up to date on all new IEC publications Just Published details all new publications released Available online and also once a month by email I E C Cu stom er Servi ce Cen tre - websto re i ec ch /csc If you wish to give us your feedback on this publication or need further assistance, please contact the Customer Service Centre: csc@iec.ch I E C 61 90-1 -1 ® Edition 3.0 201 5-05 I N TE R N ATI ON AL STAN DAR D Opti cal am pl i fi ers – Test m eth o d s – Part -1 : Power an d g n param eters – Opti cal spectru m an al yzer m eth od INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 33.1 80.30 ISBN 978-2-8322-2669-8 Warn i n g ! M ake su re th a t yo u o btai n ed th i s pu bl i c ati o n fro m an au th ori zed d i stri bu to r ® Registered trademark of the International Electrotechnical Commission –2– I EC 61 290-1 -1 : 201 © I EC 201 CONTENTS FOREWORD Scope N orm ati ve references Term s, defi n itions and abbrevi ati ons Term s and defi n i ti ons Abbreviati ons Apparatus Test sam ple Procedure Calcu lation Test resu l ts 1 Bibl i ograph y Fig u re – Typical arran g em ent of the optical spectrum an al yzer test apparatus for gai n and power m easurem ents I EC 61 290-1 -1 :201 © I EC 201 –3– I NTERNATI ON AL ELECTROTECH NI CAL COMMI SSI ON OPTICAL AMPLIFIERS – TEST METHODS – Part -1 : Power and gain parameters – Optical spectrum analyzer method FOREWORD ) Th e I n ternati on al El ectrotechn i cal Com m i ssi on (I EC) i s a worl d wi d e org an i zati on for stan dardi zati on com pri si n g al l n ati on al el ectrotech ni cal com m i ttees (I EC N ati onal Com m i ttees) The obj ect of I EC i s to prom ote i n ternati on al co-operati on on al l questi on s concern i n g stand ardi zati on i n th e el ectri cal an d el ectroni c fi el ds To thi s end and i n addi ti on to other acti vi ti es, I EC pu bl i sh es I n ternati on al Stan dards, Tech n i cal Speci fi cati ons, Tech ni cal Reports, Pu bl i cl y Avai l abl e Speci fi cati on s (PAS) an d Gu i des (h ereafter referred to as “I EC Publ i cati on (s) ”) Thei r preparati on i s entru sted to techn i cal com m i ttees; an y I EC Nati on al Com m i ttee i n terested i n th e su bj ect deal t wi th m ay parti ci pate i n th i s preparatory work I nternati on al , g overn m ental an d n on g overn m ental org an i zati ons l i si n g wi th th e I EC al so parti ci pate i n thi s preparati on I E C col l aborates cl osel y wi th th e I n tern ati onal Org an i zati on for Stan d ardi zati on (I SO) i n accordan ce wi th di ti on s determ i ned by ag reem en t between th e two org ani zati ons 2) Th e form al deci si on s or ag reem en ts of I EC on tech ni cal m atters express, as n earl y as possi bl e, an i nternati on al sen su s of opi ni on on th e rel evant su bj ects si n ce each tech ni cal com m i ttee h as representati on from al l i n terested I EC N ati onal Com m ittees 3) I EC Pu bl i cati on s have th e form of recom m endati on s for i n tern ati onal use an d are accepted by I EC N ati onal Com m i ttees i n th at sense Whi l e al l reasonabl e efforts are m ade to ensure th at th e tech n i cal content of I EC Publ i cati on s i s accu rate, I EC can n ot be h el d respon si bl e for th e way i n wh i ch th ey are u sed or for an y m i si nterpretati on by an y en d u ser 4) I n order to prom ote i n tern ati onal u ni form i ty, I EC N ati on al Com m i ttees un d ertake to appl y I EC Pu bl i cati on s transparentl y to the m axi m um extent possi bl e i n th ei r nati on al an d reg i on al publ i cati ons An y d i verg ence between an y I EC Pu bl i cati on an d the correspon di ng nati on al or reg i on al pu bl i cati on sh al l be cl earl y i n di cated i n the l atter 5) I EC i tsel f d oes n ot provi de an y attestati on of form i ty I n depend ent certi fi cati on bodi es provi de form i ty assessm ent servi ces an d, i n som e areas, access to I EC m arks of form i ty I EC i s not respon si bl e for an y servi ces carri ed out by i n d epen den t certi fi cati on bodi es 6) Al l u sers sh ou l d en su re th at th ey h ave th e l atest edi ti on of thi s pu bl i cati on 7) N o l i abi l i ty shal l attach to I EC or i ts di rectors, em pl oyees, servants or ag en ts i ncl u di n g i n di vi du al experts an d m em bers of i ts tech n i cal com m i ttees and I EC Nati on al Com m i ttees for any person al i n j u ry, property d am ag e or other dam ag e of any n atu re wh atsoever, wheth er di rect or i n di rect, or for costs (i n cl u d i n g l eg al fees) and expenses ari si ng out of th e pu bl i cati on, u se of, or rel i an ce upon, th i s I EC P ubl i cati on or an y oth er I EC Publ i cati ons 8) Atten ti on i s drawn to th e N orm ati ve referen ces ci ted i n th i s pu bl i cati on U se of th e referen ced publ i cati ons i s i n di spensabl e for th e correct appl i cati on of th i s publ i cati on 9) Atten ti on i s drawn to th e possi bi l i ty th at som e of th e el em en ts of th i s I EC Pu bl i cati on m ay be the su bj ect of paten t ri g hts I EC sh al l n ot be h el d responsi bl e for i denti fyi ng an y or al l such paten t ri g h ts I n tern ati on al Stan dard I EC 61 290-1 -1 has been prepared by su bcom m ittee 86C: Fi bre optic system s and acti ve devices, of I EC techn ical com m ittee 86: Fi bre optics This th ird editi on cancels an d replaces the secon d edi ti on pu blish ed i n 2006 an d constitu tes a tech nical revisi on This edi ti on incl u des the foll owi ng si g n ifican t techn ical chan ges wi th respect to the previ ou s edi tion: a) updates on th e ch aracteristics of m easurem en t apparatus; b) revised l ist of addressed optical am pl ifi er param eters –4– I EC 61 290-1 -1 : 201 © I EC 201 The text of th is stan dard is based on the fol lowi n g docum en ts: FDI S Report on voti n g 86C/1 309/FDI S 86C/1 328/RVD Fu l l inform ati on on th e voti ng for th e approval of th is stan dard can be fou nd i n th e report on voting in dicated in th e above table This publicati on has been drafted i n accordance wi th th e I SO/I EC Directi ves, Part This stan dard sh al l be used in conj unction with I EC 61 290-1 an d I EC 61 291 -1 A l ist of al l parts of th e I EC 61 290 series, pu blish ed u nder th e g eneral titl e Test methods can be fou nd on th e I EC websi te Optical amplifiers – The com m ittee h as decided that the ten ts of th is pu blicati on wi l l rem ain unch ang ed u nti l th e stabi li ty date in dicated on the I EC website un der "h ttp://webstore iec ch " i n th e data related to th e specific pu blicati on At th is date, th e pu bl ication wi ll be • reconfi rm ed, • wi thdrawn , • repl aced by a revised editi on, or • am ended A bi l in g ual versi on of th is pu bl icati on m ay be issu ed at a l ater date ————————— Th e fi rst edi ti on s of som e of th ese parts were pu bl i sh ed u n d er th e g en eral ti tl e specification or Optical amplifier test methods Optical fibre amplifiers – Basic I EC 61 290-1 -1 :201 © I EC 201 –5– OPTICAL AMPLIFIERS – TEST METHODS – Part -1 : Power and gain parameters – Optical spectrum analyzer method Scope This part of I EC 61 290 appl ies to all com m erci all y avai labl e optical am plifi ers (OAs) an d optical l y am plifi ed m odu les I t applies to OAs using optical l y pum ped fi bres (OFAs based on either rare-earth doped fibres or on th e Ram an effect) , sem icon ductor OAs (SOAs) an d plan ar optical waveg u i de am plifiers (POWAs) The obj ect of th is standard is to establ ish un iform requ irem ents for accurate an d reliable m easurem ents, by m ean s of th e optical spectru m anal yzer test m ethod, of th e foll owi ng OA param eters, as defin ed in I EC 61 291 -1 : a) b) c) d) e) nom i nal ou tput sig n al power; g n; pol ari zati on-dependent g ain ; m axim um ou tpu t sig n al power; m axim um total output power NOTE Al l n um eri cal val ues fol l owed by (‡) are su g g ested val ues for whi ch th e m easurem en t i s assured The object of th is standard is specifical l y di rected to sin g le-ch ann el am plifiers For m ultich ann el am pl ifiers, on e sh oul d refer to th e I EC 61 290-1 seri es [1 ] Normative references The foll owi ng docum en ts, i n wh ole or i n part, are norm ati vel y referenced i n th is docum en t and are in dispensabl e for i ts appl ication For dated references, on l y the edition cited applies For un dated references, th e l atest editi on of th e referenced docum en t (i nclu ding an y am endm ents) appli es I EC 61 290-1 , Optical amplifiers - Test methods - Part 1: Power and gain parameters I EC 61 291 -1 , Optical amplifiers - Part 1: Generic specification Terms, definitions and abbreviations 3.1 Terms and definitions For the purposes of th is docum en t, the term s an d defi n iti ons given i n I EC 61 291 -1 appl y 3.2 ASE DBR DFB Abbreviations am pl ified spon tan eous em ission distri bu ted Brag g refl ector (laser di ode) distri bu ted feed-back (l aser diode) ————————— N u m bers i n sq uare brackets refer to the Bi bl i og raphy –6– ECL LED OA OFA POWA SOA I EC 61 290-1 -1 : 201 © I EC 201 external cavi ty l aser (diode) lig h t em ittin g diode optical am pl ifi er optical fi bre am pl ifi er plan ar optical waveg u i de am pl ifier sem iconductor optical am plifi er Apparatus A di agram of th e m easurem ent set-up is g iven in Fi gu re Optical source J1 dB Polarization controller (optional) Optical power meter Variable optical attenuator IEC Figure a – Calibration Optical source J1 dB J2 Polarization controller (optional) Optical spectrum analyzer Variable optical attenuator IEC Figure b – Input signal power measurement Optical source dB Variable optical attenuator J1 Polarization controller (optional) J2 OA OA under test Optical spectrum analyzer IEC Figure c – Output power measurement Figure – Typical arrangement of the optical spectrum analyzer test apparatus for gain and power measurements The test equ ipm ent listed below, with th e requ ired characteristics, is needed a) optical source: The optical source sh al l be ei ther at fixed wavel eng th or wavel en g th -tu n eable – fixed-wavelength optical source: This optical source sh all g en erate a l ig ht with a wavelen gth and optical power specified i n th e relevant detail specificati on Un less oth erwise specifi ed, the optical source shal l em it a tin u ous wave with the fu ll wi dth at h alf m axim um of th e spectrum narrower th an nm (‡) A distri bu ted feed-back (DFB) l aser, a distri bu ted Brag g reflector (DBR) l aser, an external cavi ty l aser (ECL) diode an d a l ig h t em itti n g diode (LED) wi th a n arrow-ban d fi lter are appl icabl e, for exam ple The su ppressi on rati o for th e si de m odes for the DFB laser, th e DBR l aser or th e ECL I EC 61 290-1 -1 :201 © I EC 201 –7– shall be hi g her th an 30 dB (‡) The output power fl uctuation sh all be less than 0, 05 dB (‡) , wh ich m ay be better attai n able wi th an optical isol ator at th e outpu t port of th e optical source Spectral broaden ing at th e foot of th e l asin g spectru m shal l be m in im al for laser sources and the ratio of th e sou rce power to total spontaneou s em ission power of th e l aser shall be m ore th an 30 dB; – wavelength-tuneable optical source: This optical source shall be abl e to gen erate a wavelen g th-tu n abl e li g ht wi thin th e ran ge specifi ed i n th e relevan t detai l specification I ts optical power sh al l be specified in th e relevant detai l specificati on U n less oth erwise specifi ed, the optical source shall em it a tin u ous wave with the fu ll wi dth at half m axim um of th e spectrum n arrower than nm (‡) An ECL or an LED wi th a narrow bandpass optical filter is appl icabl e, for exam pl e Th e su ppressi on rati o of si de m odes for th e ECL sh all be h ig h er th an 30 dB (‡) Th e output power fl uctuation sh al l be l ess th an 0, 05 dB, wh ich m ay be m ore easi l y attainable wi th an optical isolator at th e output port of the optical source Spectral broaden i ng at the foot of the lasin g spectrum shall be m in im al for th e ECL Spectral broaden i ng at th e foot of th e lasin g spectrum shall be m in im al for l aser sou rces an d th e ratio of th e source power to total spon tan eou s em ission power of the laser sh al l be m ore th an 30 dB The use of an LED shal l be l im ited to sm al l-si g nal g ain m easurem ents b) optical power meter: I t sh all h ave a m easurem ent u ncertain ty better than ± 0, dB, irrespecti ve of th e state of polari zation , with i n th e operati onal wavelen gth ban dwidth of th e OA A d yn am ic ran ge exceedin g the m easured gai n is requ ired (e g 40 dB) ; c) optical spectrum analyzer: Withi n th e operation al wavel eng th ban dwi dth of the OA, th e l i n earity of th e spectral power m easurem ent shal l be better than th e desired g ain u ncertain ty an d at m ost ± 0, dB, an d th e am pl itu de stabi l ity of th e spectral power m easu rem ent sh al l be better than the desired power u ncertai n ty an d at least better than ±0, dB over the durati on of th e m easurem ent Pol arization dependence of th e spectral power m easu rem ent sh all be better than ± 0, dB The wavel en g th m easurem ent uncertai nty shall be better th an ± 0, nm A d yn am ic ran g e exceedin g th e m easured g n is requ ired (e g 40 dB) Th e spectral resol ution sh all be equ al or better th an nm ; d) optical isolator: Optical isol ators m ay be used to bracket th e OA The polari zati on -depen den t l oss variation of the isolator shal l be better than 0, dB (‡) Optical isolation sh al l be better th an 40 dB (‡) The reflectance from th is device sh al l be sm al ler than –40 dB (‡) at each port; e) variable optical attenuator: The attenu ati on ran g e and stabil ity sh al l be over 40 dB (‡) an d better th an ± 0, dB (‡) , respecti vel y Th e refl ectance from th is device sh all be sm aller th an –40 dB (‡) at each port; f) polarization controller: This device sh all be able to provide as in put si gn al li g ht all possi ble states of polari zati on (e g lin ear, el li ptical and ci rcu l ar) For exam ple, the pol arization trol l er m ay consist of a l i near polari zer fol lowed by an al l-fibre-type pol ari zati on trol ler, or by a li n ear pol ari zer foll owed by a quarter-wave pl ate rotatable by m in im u m of 90°, an d a half wave plate rotatable by m i nim um of 80° The loss vari ation of th e polari zati on control ler sh all be less than 0, dB (‡) The reflectance from th is device sh al l be sm all er than –40 dB (‡) at each port Th e u se of a polari zati on trol l er is consi dered opti onal, except for the m easu rem ent of polari zation depen den t g n , bu t m ay also be n ecessary to ach i eve the desired u ncertain ty of oth er power and g n param eters for OA devices exh ibi tin g si gn ificant pol ari zation dependent g n ; g) optical fibre jumpers: The m ode fiel d di am eter of the optical fibre j um pers used shall be as close as possibl e to th at of fi bres used as i n pu t an d ou tpu t ports of the OA Th e reflectance from th is device shall be sm al ler than –40 dB (‡) at each port, and th e l en g th of th e j u m per shal l be sh orter th an m ; –8– I EC 61 290-1 -1 : 201 © I EC 201 Standard optical fibres type B1 as defi ned in I EC 60793-2-50 [2] are recom m ended However, other fibre types m ay be used as in pu t/output fi bre I n th is case, type of fi bre wi l l be considered h) optical connectors, J1 and J2: The n ecti on l oss repeatabi l i ty shal l be better th an ± 0, dB Test sample The OA un der test shal l operate at n om in al operati ng di tions I f th e OA is likel y to cause laser oscil lations du e to un wan ted refl ecti ons, optical isol ators sh al l be u sed to bracket th e OA u n der test This wi ll m inim ize th e si gn al i nstabil i ty and th e m easurem ent u ncertain ty For m easu rem ents of th e param eters of Cl ause , care shal l be taken in m ain tai n in g the state of polarizati on of the in put l ig ht durin g the m easu rem ent Ch ang es i n the pol ari zati on state of th e in pu t l igh t m ay resul t i n i nput optical power chan ges because of th e sl ig h t polarization depen dency expected from al l the optical com pon ents used, th is leadin g to m easu rem en t errors Procedure The procedure is as fol l ows: a) Gain and nominal output signal power: This m eth od perm its determ in ati on of the g ain th rou g h th e m easu rem en ts of th e OA i nput si gn al power, P i n , th e OA outpu t power, Pou t , an d th e OA am plifi ed spon taneous em ission (ASE) power, PASE at the si g nal wavelen gth The m easurem ent procedures described bel ow shal l be fol lowed: ) set th e optical source at the test wavel eng th specifi ed i n th e relevan t detail specification Set the optical sou rce an d th e vari able optical attenu ator in a way to provide, at th e in pu t port of the OA, the optical power Pi n specifi ed in th e rel evant detai l specification; 2) m easu re P i n with th e optical power m eter, as shown i n Fi g ure a, to cali brate the optical spectrum an al yzer; 3) m easure Pi n wi th the optical spectrum an al yzer, as sh own i n Fig ure b; 4) m easu re P ou t wi th the optical spectrum anal yzer, as sh own i n Fig ure c; 5) m easure PASE wi th the optical spectrum anal yzer, as shown in Fig ure c, according to th e tech n iqu e specified i n th e rel evan t detail specificati on; I n cases using a pol ari zati on control ler, th e foll owi ng procedu re sh al l be u sed: 6) m easure P ou t by adj ustin g th e polari zation trol l er un til a m in im um Pou t is ach ieved an d repeat step 5) Various tech ni ques for P ASE m easurem en ts are appl icable On e tech niqu e m akes use of an in terpol ati on procedure to eval uate th e ASE level at th e sign al wavel eng th by m easurin g th e ASE l evel at wavel en g th offset to both side of sig nal wavelen gth on the optical spectru m anal yzer display Another techn i qu e em pl oys a polarizer, placed between th e variabl e optical atten uator an d th e OA u nder test, to elim in ate th e si g nal com pon en t from the OA ou tput to m easure th e ASE l evel withou t bei n g affected by the am pl ifi ed si gn al spectru m I n th e latter case, the i n pu t optical sig nal sh all be l in earl y polari zed wi th an extinction rati o better th an 30 dB (‡) , an d P ou t shall be calcu lated as an averag ed value overal l th e polarization states I f the pol ari zer techn i que can not sufficientl y el im i n ate th e si gn al power, th e interpol ation techn i qu e can be u sed in additi on to th e pol arizer techn i que Optical n ectors J and J sh all n ot be rem oved du ri n g th e m easurem ent to avoid m easurem ent errors du e to re-con nection b) Polarization-dependent gain variation: I EC 61 290-1 -1 :201 © I EC 201 –9– As in a) , bu t use a pol ari zati on controller between th e vari able optical atten u ator an d th e n ector J (see Fi g ure ) , repeat al l procedu res at differen t states of polari zation as specified i n the rel evan t detail specificati on, an d repl ace procedu re ) wi th th e fol lowi n g: ) set th e optical sou rce to th e test wavel en gth specified in th e relevant detail specificati on Set the polarization troll er at a g iven state of pol arization as specifi ed i n th e relevant detail specification Set the optical source and the vari abl e optical atten u ator in a way to provi de, at th e in put port of th e OA, th e optical power Pi n specifi ed in th e relevant detai l specification c) Maximum output signal power: As in a) , bu t th is param eter is determ in ed by repeatin g al l steps at different wavelen gths specified i n detailed specificati on, an d repl ace steps ) , 4) , an d 6) wi th the fol l owing : ) set the wavelen gth-tu n eabl e optical sou rce at the test wavelen gth specifi ed in th e relevant detai l specificati on Set th e optical source an d th e variable optical atten uator in a way to provide, at th e i nput port of th e OA, the m axim um inpu t optical power Pi n m ax specified in the rel evant detai l specificati on ; 4) acti vate OA an d adjust the m axim um pu m p power or m axim um pu m p cu rren t of OA to th e n om in al di ti on as specified i n th e rel evan t detai l specificati on When the OA un der test is integ rated with trol circu i try, the OA sh all be tested wi th constan t pum p power m ode or constant pum p cu rren t m ode and m easure P ou t wi th th e optical spectrum an al yzer, as sh own i n Fig ure c; 6) m easure m axim um output sig n al power by adj usti n g th e pol ari zation troll er u nti l a m axim um Pou t is ach i eved, an d repeat a) , step 5) d) Maximum total output power: Sam e procedure as for c) The state of polarization of the i n pu t sig n al sh al l be ch ang ed after each m easurem ent of Pi n , P ou t an d PASE by m eans of the pol ari zation control ler, so th at substanti al l y al l th e states of polari zation, in princi ple, are successivel y l au nch ed into the in put port of th e OA u n der test The pol ari zation controll er shal l be operated as specified i n th e relevant detail specificati ons A possi ble way, wh en u si ng a l in ear pol ari zer fol lowed by a qu arter-wave rotatabl e plate, is th e fol lowi n g : the l in ear pol arizer is adj usted so that th e OA output power is m axim ized; th e qu arter-wave plate is then rotated by a m in im um of 90 ° step-by-step At each step, th e halfwave pl ate is rotated by a m in im u m of 80 ° step-by-step An other possi ble way is to select fou r kn own an d specified states of pol arization to all ow m atrix calcu l ation of the resu l tin g pol ari zati on depen den t g ain A short optical j um per at th e OA i npu t, kept as straig ht as possibl e, sh all be used, in order to m inim i ze th e chan ge of the state of polari zation i nduced i n i t by possible stress an d an isotropy The pol arization -dependen t l oss variati on of th e optical n ector sh all be l ess than 0, dB (‡) Calculation The calcu l ations shal l be m ade as fol l ows: a) Nominal output signal power: The nom inal ou tput sig n al power Psi g -out-n om (in dBm ) shall be calcu lated as: Psi g -out-nom = l og ( P out – PASE ) + L bj (dBm ) wh ere Pou t is the recorded absolu te valu e of ou tpu t optical si gn al power (i n mW) ; – 10 – PASE L bj I EC 61 290-1 -1 :201 © I EC 201 is th e recorded absolu te valu e of ou tput ASE power throu g h the optical bandpass fil ter (i n mW) ; is th e insertion loss of the fibre j um per placed between th e OA an d th e optical power m eter (i n dB) N OTE Th e m easu rem ent error can be better than , dB (‡) , d ependi n g on the opti cal spectrum an al yzer u ncertai n ty b) Gain: The gai n G at th e si g nal wavelen g th sh al l be calcu lated as: G = ( Pout – PASE ) / Pi n (l in ear u n its) G = log [( Pout – PASE ) / Pi n ] (dB) or N OTE Th e sm al l -si g n al reg i m e i s the ran g e of i n pu t si g n al power su ffi ci en tl y sm al l so th at the OA u n d er test operates i n th e l i near reg i m e Th i s reg i m e can be establ i shed by pl otti n g G versu s P i n The l i n ear reg i m e dem ands Pi n to be i n the rang e wh ere th e g n i s qu i te i n depen dent from P i n An i n put si g nal power rang i n g from –30 dBm to –40 dBm g en eral l y i s wel l wi th i n th i s ran g e N OTE The m easu rem en t error can be better than ± , dB (‡) , d epen di n g on th e opti cal spectru m anal yzer u ncertai n ty, m nl y i n term s of i ts pol ari zati on depen dency I f l i n earl y pol ari zed l i g ht (i e l i g h t g en erated by a l aser) and a pol ari zati on trol l er are u sed, th e m easu rem ent error can be m u ch reduced by adj usti n g th e state of pol ari zati on of the i n pu t si g n al to th e OA so th at th e opti cal spectrum an al yzer al ways i nd i cates th e m i nim u m (or m axi m um ) si g nal power i n each m easu rem ent On th e oth er han d, an LED an d a m on ochrom ator can be used as an opti cal sou rce to red uce the opti cal spectrum an al yzer error to ± 0, dB, si nce LEDs em it u npol ari zed l i g h t H owever, i t i s to be n oted th at th e opti cal power l evel obtai n abl e from such a sou rce i s m uch l ower th an th at of a l aser c) Polarization-dependent gain: Calcu late th e gai n val u es at th e differen t states of pol ari zati on , as i n 7, poi nt b) above I dentify th e m axim um , Gm ax , and the m i nim um , Gm i n , gai n as the h ig h est and the l owest of all these g n valu es, respectivel y The polari zati on-depen den t g n vari ation ∆ Gp sh all be calcu lated as fol lows: ∆ Gp = Gm ax-pol – Gm i n-pol (dB) N OTE ∆ Gp does n ot necessari l y i n di cate th e possi bl e m axi m um vari ati on of the pol ari zati on depen den cy I n fact, the evol uti on of the state of pol ari zati on i n si de th e OA depen ds on tem peratu re an d other param eters, an d th e attenuati on th rou g h the OA u n der test i s m axi m u m onl y when each i nput state of pol ari zati on si m u l tan eousl y yi el ds m axi m u m attenu ati on for each com pon en t i n th e OA un der test N OTE Th e m easurem en t error can be better th an ± dB (‡) , depen di n g on th e opti cal spectrum anal yzer un certai nty, m nl y i n term s of i ts pol ari zati on depen dency d) Maximum output signal power: The m axim um ou tpu t si g nal power P si g -out-m ax (in dBm ) shal l be calcul ated as: Psi g -out-m ax = Pout-m ax – P ASE (l in ear u n its) Psi g -out-m ax = l og ( P ou t-m ax – PASE ) (dBm ) wh ere Pou t-m ax is th e recorded absol ute m axim u m val ue of ou tpu t optical power (i n mW); e) Maximum total output power: The m axim u m total ou tpu t power P ou t-m ax (in dBm ) sh al l be calcu l ated as: Pout-m ax = log ( P out-m ax ) wh ere (dBm ) I EC 61 290-1 -1 : 201 © I EC 201 – 11 – Pou t-m ax is th e recorded absol ute m axim u m val ue of ou tpu t optical power (in mW) Test results Test resu lts are as fol l ows: a) Nominal output signal power: The fol lowi ng detai ls sh al l be presented ) arran g em ent of the test set-u p; 2) type of optical source; 3) i ndication of the optical pum p power (if applicable) ; 4) operati n g tem perature (when requ ired) ; 5) input sig n al optical power, Pi n ; 6) resol uti on ban dwidth of the optical spectrum anal yzer; 7) wavelen g th of th e m easu rem ent b) Gain: The detai ls ) to 7) , previousl y l isted for n om in al ou tpu t sig n al power, shal l be presen ted an d, i n addition 8) gain c) Polarization-dependent gain: The detai ls ) to 7) , previ ousl y l isted for n om in al ou tpu t sig n al power, shal l be presen ted an d, i n addition 8) polari zati on depen dency of th e optical spectrum anal yzer power u ncertain ty; 9) th e m axim um and m in im um gai n, Gm ax-pol an d Gm i n-pol ; 0) pol ari zati on-dependent g ain variati on; 1 ) chan ge in th e state of polari zation g iven to the in put sig n al l ig ht d) Maximum output signal power: The detai ls ) to 7) , previousl y l isted for th e nom inal ou tpu t sig nal power, sh al l be presented and, i n addition 8) m axim um ou tpu t si gn al power Psi g -out-m ax e) Maximum total output power: The details ) to 7) , previou sl y l isted for th e nom i nal ou tpu t sig nal power, sh all be presented and, in addi ti on 8) m axim um total output power Pout-m ax – 12 – I EC 61 290-1 -1 :201 © I EC 201 Bibliograph y [1 ] [2] I EC 61 290-1 (all parts) , parameters Optical amplifiers – Test methods – Part 10: Multichannel I EC 60793-2-50, Optical fibres – Part 2-50: Product specifications – Sectional specification for class B single-mode fibres _ I N TE RN ATI O N AL E LE C TR OTE C H N I C AL CO M M I S SI O N , ru e d e Vare m bé PO Box 31 CH -1 21 G e n e va S wi tze rl an d Te l : + 41 Fax: + 22 9 1 22 9 0 i n fo @ i e c ch www i e c ch