光有源器件介紹

光有源器件

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光無源器件光器件：光通信網(wǎng)絡(luò)的基礎(chǔ)光有源器件定義：需要外加能源驅(qū)動(dòng)工作的光電子器件半導(dǎo)體光源(LD,LED,DFB,QW,SQW,VCSEL)半導(dǎo)體光探測(cè)器(PD,PIN,APD）光纖激光器（OFL:單波長(zhǎng)、多波長(zhǎng)）光放大器(SOA,EDFA)光波長(zhǎng)轉(zhuǎn)換器(XGM,XPM,FWM)光調(diào)制器（EA）光開關(guān)/路由器光無源器件定義：不需要外加能源驅(qū)動(dòng)工作的光電子器件光纖連接器（固定、活動(dòng),FC/PC,FC/APC）光纖定向耦合器/分支器光分插復(fù)用器（OADM)光波分/密集波分復(fù)用器（WDM/DWDM)光衰減器（固定、連續(xù)）光濾波器（帶通、帶阻）光纖隔離器與環(huán)行器（偏振有關(guān)、無關(guān)）光偏振態(tài)控制器、光纖延遲線、光纖光柵光器件與電器件的類比多波長(zhǎng)光源DWDM光調(diào)制器光隔離器光耦合器光波長(zhǎng)轉(zhuǎn)換光放大DWDM光色散補(bǔ)償光隔離器光環(huán)行器光波長(zhǎng)轉(zhuǎn)換OADMDWDM光隔離器光環(huán)行器光開關(guān)光器件的應(yīng)用可調(diào)諧濾波DWDMOXC光耦合器光調(diào)制解調(diào)光器件的分類光電變換器件光開關(guān)與調(diào)制器件光放大器件光色散補(bǔ)償器件光網(wǎng)絡(luò)器件光電變換器件F-P腔激光二極管(LD)分布反饋布拉格激光器(DFB)分布布拉格反射激光器(DBR)外腔激光器與Q開關(guān)激光器發(fā)光二極管(LED)光纖激光器(OFL)垂直腔表面發(fā)射激光器(ECSEL)多波長(zhǎng)光源與波長(zhǎng)可調(diào)諧激光器光電探測(cè)器(PD、PIN、APD)

光調(diào)制器件幅度調(diào)制機(jī)械調(diào)制電光調(diào)制直接調(diào)制電吸收光調(diào)制(EA)相位調(diào)制偏振調(diào)制光電集成芯片(OEIC)光子集成芯片(PIC)光放大器件摻鉺光纖放大(EDFA)摻鐠光纖放大(PDFA)摻釹光纖放大(NDFA)分布式光纖放大喇曼光纖放大(SRFA)布里淵光纖放大(SBFA)半導(dǎo)體光放大(SOA)

光色散補(bǔ)償器件色散控制色散位移單模光纖非零色散位移單模光纖大有效截面單模光纖色散平坦單模光纖色散補(bǔ)償色散補(bǔ)償光纖模塊SOA色散補(bǔ)償光纖光柵色散補(bǔ)償色散管理光網(wǎng)絡(luò)器件光耦合透鏡（自聚焦透鏡、玻璃球透鏡）光連接器與光耦合器光隔離器與光環(huán)行器光濾波與光波分復(fù)用器件光起偏器與偏振控制器光波長(zhǎng)轉(zhuǎn)換與光波長(zhǎng)路由器件光調(diào)制解調(diào)器（Modem）光衰減器與光延時(shí)器件光開關(guān)與光交叉連接器件微光電機(jī)械芯片元件：Components器件：Devices模塊：Modules系統(tǒng)：SystemsOpticalComponentTechnologiesOpticalfibretechnologyMicrooptictechnologyPlanarwaveguidetechnologyMicro-Optic-Electronic-MechanictechnologyFibreTechnology

Fibreisnotonlyatransmissionmedium.Manydevicessuchasamplifiersandfilterscanbemadefromfibre.Componentsusuallyendupconnectedtoafibrefortransmission.Microoptics

Devicesaremadeusingtraditionalopticalcomponents(suchaslenses,prismsanddiffractiongratings)assembledtogether.Makingverysmall,veryhighprecisioncomponentsandassemblingthemintousefuldevicestotoleranceswelllessthanonemicronisverydifficultandexpensivetoaccomplish.PlanarWaveguideTechnology

Devicesareconstructedonthesurfaceofaflatpieceofmaterialsuchassilicaorsemiconductorcrystalusingthetechniquesofsemiconductorchipmanufacturing.PlanarOpticalDevicesAdvantagesBuildadevicesmuchmoreefficientlyandwithmuchlowercost.Physicallyquitesmallandbebuiltwithverygreatprecision.CriticaldimensionscanbecontrolledmuchmoreaccuratelyThereareanumberofdevicesthatcan'tbebuiltanyotherway.Manydevicescanbemadetogetheronasinglelargesubstrateandlatercutupintoindividualdevices.DifficultiesNeedtocontroldimensionsaccuratelytoabout.25ofamicron.Whendiagonalwaveguideshaveregularlyccurringstepsintheirsides,youhappentochanceonaresonantwavelength.Manycomplexdevicescan'tbedoneinplanartechnologybecauseaplanardeviceismadefromauniformmaterial.Itiscostlyanddifficulttoconnectthesedevicestofibres.Fabricationof

PlanarOpticalDevicesDiffusionofadopantintoaflatubstrate.Deposition/etchingtechniquessimilartothoseusedinmakingsemiconductors.Directwritingofwaveguidesusingapowerfullaserbeamandphotosensitivedopantinthematerial(suchasgermaniuminsilicaglass).Deposition/Etching

DiffusionTechniques

Asilicaorglasssubstrate(ratherthanasiliconone)isused.Thesurfaceiscoveredwithamasktocoverthepartsofthedevicethatwedon'twanttobecomewaveguiding.Theblankisthensubjectedtoprolongedexposure(usuallyatahightemperature)toamaterialwhichcandiffuseitswayintothesurfaceandsoformawaveguide.IonExchangeTechniquesAnexampleoftheionexchangetechniquewouldbewheresodaglass(withahighsodiumcontent)isusedasthesubstrate.Aftermasking,thesubstrateisimmersedinmoltenpotassiumnitrate.Potassiumionsdiffuseintotheunmaskedpartsoftheglassandsodiumionsdiffuseout.Thustheionsareexchanged-KreplacesNa.thisincreasestheRIandformsawaveguide.DirectWritingwith

aUVBeam

Asmallsheetoffusedsilicadopedwithgermaniumisused.This“blank”ispolisheduntilthesurfaceisveryflat.AUVlaserbeam(244nm)atveryhighintensityisthenusedtoexposetheareasonthesurfacethataretobeofhigherRI.OpticalAmplifiersWhatisanOpticalAmplifierAnopticalamplifierisadevicewhichamplifiestheopticalsignaldirectlywithouteverchangingittoelectricity.Thelightitselfisamplified.HowtomakeanOAAmplifierscanbebuiltinsemiconductor:SemiconductorOpticalAmplifiers(SOAs).Almostanysemiconductorlasercanbemadeintoanamplifierwithafewmodifications-

Amplifierscanbebuiltinfibres:FibreAmplifiersEDFA:ErbiumDopedFibreAmplifiers PDFA:PraseodymiumDopedFibreAmplifiersNDFA:NeodymimumDopedFibreAmplifiersSRFA:StimulatedRamanFibreAmplifiersPFA:PlasticFibreAmplifierPrinciplePumpingEnergySignalinSignalout1550EDFA增益窗口30nm~60nm光放大器增益光纖衰減除去OH峰外>300nm低損耗窗口波長(zhǎng)nm8501310PDFASOASRADevelopmentofOAEDFA增益窗口30nm~60nmPDFASOASRAEDFAsEnergyLevelStates

ofErbium

TechnicalCharacteristics

ofEDFAsEfficientpumpingMinimalpolarisationsensitivityLowinsertionlossHighoutputpower(thisisnotgainbutrawamountofpossibleoutputpower)LownoiseVeryhighsensitivityLowdistortionandminimalinterchannelcrosstalkDefinitionsGain(amplifier):theratioindecibelsofinputpowertooutputpower.GainCoefficient:thesmallsignalgaindividedbythepumppower.Bandwidth:therangeofwavelengthsoverwhichtheamplifierwilloperate.DefinitionsGainSaturation:thepointwhereanincreaseininputpowerceasestoresultinanincreaseinoutputpower.

PolarisationSensitivity:thedifferenceingainofaninputsignalinonepolarisationtothegainintheorthogonalpolarisation.(typical.01~.1dB).NoiseFigure:theratiooftheSNRattheinputtotheSNRattheoutput(indecibels).GainCharacteristicsofEDFAsResponseofCascadedEDFAsFlatteningtheGainCurveOperatingthedeviceat77oK.Introducingotherdopantmaterials(suchasaluminiumorytterbium)alongwiththeerbiumintothefibrecore.Amplifierlengthisanotherfactorinfluencingtheflatnessofthegaincurve.Controllingthepumppower(throughafeedbackloop)isroutinetoreduceASE.

FlatteningtheGainCurveAddinganextraWDMchannellocallyattheamplifier.Thisiscalled“gainclamping”.Manipulatingtheshapeofthefibrewaveguidewithintheamplifier.Fibreswithdualcoreshaverecentlybeenshowntoproducemuchsuperiorgainflatnesscharacteristics.FlatteningtheGainCurveUsing“blazed”fibreBragggratingsasfilterstoreducethepeaksintheresponsecurve.Inotherwords,reducetheresponseatallwavelengthstothatoftheworstwavelength.Thisapproachhasbeenreportedtoworkwellinfieldtrials.Usingchannelpreemphasisonthesignalsastheyaretransmitted.Thatis,transmitdifferentWDMchannelsatdifferentpowerlevelstocompensateforlateramplifiergaincharacteristics.LPG

for

FlatteningtheGain

GainClampingEDFACouplerFilterCouplerEDFA光放大器增益鎖定技術(shù)泵浦源功率控制飽和光控制技術(shù)光功率檢測(cè)控制輸入光功率檢測(cè)輸出光功率檢測(cè)PinPout泵浦激光器EDFWidebandEDFAsusualgainwindow(S-&C-band)1525-1565nmSecondgainwindow(L-band)1570-1610nmUsingco-dopants,principallyaluminiumandphosphorusWidebandEDFAs

80nm.GainSaturationCo-DopantsCommonco-dopantsusedarealuminium(Al),ytterbium(Yb)andgermanium(Ge).Geco-dopingproduces1536nmand1550nmgainpeaks.Albroadensandflattensthegainspectrumintheregion1540nmto1560nm.DesignofAmplifierLengthBoththesignalpowerlevelandthepumppowerlevelvaryalongthelengthoftheamplifier:signaltravelsstronger;pumppowerleveldecreases.Singlewavelengthoperation:

Lopt=f(Psig,Ppump,Ce,G)WDMoperation:theflatnessofthegain.Thegainspectrumatanypointalongtheamplifierwillbedifferentfromthespectrumatanyotherpointalongtheamplifier.SelectPumpWavelengths980nmisalmosttwiceasefficient,asapumpwavelength,than1480nm.1480iswithinthegainspectrum1480isatwo-levellasersystem1480istemperature-sensitivedisadvantageof980nm:quitenarrowpumpbandwidthWarningPumpsneedtoproduceanoutputofupto250mW.UnlessthelaserisverycarefullydesignedtoprotectityoucanburntheendfacetanderodetheLD.PumpingDirectionCladdingPumpsOutputpowersofupto10watts!MultiStageEDFAs1)Toincreasethepoweroutputwhilstretaininglownoise2)Toflattenthetotalamplifiergainresponse3)ToreduceASEnoiseRemotePumpingTwofibresareusedintheconnection-oneforthesignalandoneforthepump.topumpat1480nmInatypicalunderseasystemtoextendthedistance

fromaround100kmto150oreven200km.EDFASystemResilienceSignalpassesthroughthefailedamplifierrelativelyunchanged!UsingOTDRsinAmplifiedLinksTodiagnoselinkconditionrightthroughtheamplifier.AmplifierApplicationsPreamplifiersPowerAmplifiersLineAmplifiersSecond-GenerationEDFAsAnamplifierwithanyofthefollowingcharacteristicsis“second-generation”:Multi-stagedesignsUseofco-dopantssuchasytterbiumUseofmultiplepumpsUseofgain-equalisationtechniquesSummaryofEDFACharacteristicsItissignificantlysimplerthanarepeaterandwillhaveamuchlongermeantimetofailure.Itissignificantlylowerincostthanarepeater.Itwilloperateatalmostanyspeed.Itcanbemadephysicallysmallenoughtofitonaprintedcircuitcard.SummaryofEDFACharacteristicsItwillproduceagaininopticalsignalofabout25dB.Someamplifierscanproduceagainof50dBorevenhigher.Itwillamplifymanydifferentwavelengthssimultaneously(withsomesmalllimitations).SummaryofEDFACharacteristicsBothamplitude(pulse)modulatedandcoherent(frequencymodulated)lightaswellascableTVsignalcouldbeamplifiedwithoutdistortion.Thereise