第三章 光纤通信器件

第三章光纤通信器件

光器件：光通信网络的基础光有源器件定义：需要外加能源驱动工作的光电子器件半导体光源(LD,LED,DFB,QW,SQW,VCSEL)半导体光探测器(PD,PIN,APD）光纤激光器（OFL:单波长、多波长）光放大器(SOA,EDFA)光波长转换器(XGM,XPM,FWM)光调制器（EA）光开关/路由器光无源器件定义：不需要外加能源驱动工作的光电子器件光纤连接器（固定、活动,FC/PC,FC/APC）光纤定向耦合器/分支器光分插复用器（OADM)光波分/密集波分复用器（WDM/DWDM)光衰减器（固定、连续）光滤波器（带通、带阻）光纤隔离器与环行器（偏振有关、无关）光偏振态控制器、光纤延迟线、光纤光栅光器件与电器件的类比多波长光源DWDM光调制器光隔离器光耦合器光波长转换光放大DWDM光色散补偿光隔离器光环行器光波长转换OADMDWDM光隔离器光环行器光开关光器件的应用可调谐滤波DWDMOXC光耦合器光调制解调光器件的分类光电变换器件光开关与调制器件光放大器件光色散补偿器件光网络器件光电变换器件F-P腔激光二极管(LD)分布反馈布拉格激光器(DFB)分布布拉格反射激光器(DBR)外腔激光器与Q开关激光器发光二极管(LED)光纤激光器(OFL)垂直腔表面发射激光器(VCSEL)多波长光源与波长可调谐激光器光电探测器(PD、PIN、APD)

光调制器件幅度调制机械调制电光调制直接调制电吸收光调制(EA)相位调制偏振调制光电集成芯片(OEIC)光子集成芯片(PIC)光放大器件掺铒光纤放大(EDFA)掺镨光纤放大(PDFA)掺钕光纤放大(NDFA)分布式光纤放大喇曼光纤放大(SRFA)布里渊光纤放大(SBFA)半导体光放大(SOA)

光色散补偿器件色散控制色散位移单模光纤非零色散位移单模光纤大有效截面单模光纤色散平坦单模光纤色散补偿色散补偿光纤模块SOA色散补偿光纤光栅色散补偿色散管理光色散补偿器件色散补偿说明：Differentwavelengthstravelatslightlydifferentspeeds

(thiseffectiscalled“ChromaticDispersion”)Chromaticdispersioncausespulsebroadening

(problemathighbitratesoverlongdistances)Standardsingle-modefiber:1300nmwindowhaslowestCD1550nmlowestloss光网络器件光耦合透镜（自聚焦透镜、玻璃球透镜）光连接器与光耦合器光隔离器与光环行器光滤波与光波分复用器件光起偏器与偏振控制器光波长转换与光波长路由器件光调制解调器（OpticalModem）光衰减器与光延时器件光开关与光交叉连接器件微光电机械芯片元件：Components器件：Devices模块：Modules系统：Systems网络：Networks光器件技术光纤技术微光学（Microoptics)technology平面波导（Planarwaveguide）技术微光电机械(Micro-Optic-Electronic-Mechanic）技术光纤技术（FibreTechnology）

Fibreisnotonlyatransmissionmedium.

（光纤不仅仅是传输媒体）Manydevicessuchasamplifiersandfilterscanbemadefromfibre.（许多器件是由光纤制成，如光纤放大器、滤波器等）Componentsusuallyendupconnectedtoafibrefortransmission.（器件与光纤相连便于传输）微光学器件(Microoptics)

器件由传统的光学元件，如透镜、棱镜、衍射光栅等，装配而成尺寸小，精度高装配难度高，机械程度低较昂贵平面波导技术

采用半导体芯片制造技术，由硅或其它半导体材料在平板上所形成的器件（Devicesareconstructedonthesurfaceofaflatpieceofmaterialsuchassilicaorsemiconductorcrystalusingthetechniquesofsemiconductorchipmanufacturing)光源和光接收器/Light-emittingDiode(LED)原理：半导体PN结发光（自发辐射光）光谱：宽带光谱

应用：短距离、小容量数据通信（通过空间/多模光纤传输）KeycharacteristicsMostcommonfor780,850,1300nmTotalpoweruptoafewWSpectralwidth30to100nmCoherencelength0.01to0.1mmLittleornotpolarizedLargeNA(poorcouplingintofiber)P-3dBPpeakBW光源和光接收器/FP(Fabry-Perot)Laser

原理：半导体PN结发光＋平行平面反射腔>>>>激光光谱：多纵模光谱（Multiplelongitudinalmode，MLM)

应用：“Classic”semiconductorlaserFirstfiberopticlinks(850or1300nm)Today:short&mediumrangelinksPpeakIPThreshold光源和光接收器/FP(Fabry-Perot)LaserKeycharacteristicsMostcommonfor850or1310nmTotalpoweruptoafewmwSpectralwidth3to20nmModespacing0.7to2nmHighlypolarizedCoherencelength1to100mmSmallNA(goodcouplingintofiber)光源和光接收器/FP(Fabry-Perot)LaseryxzSOP:linearhorizontalSOP:linearvertical偏振（Polarization）说明：Mostlasersarehighlypolarized

Degreeofpolarization(DOP):

DOP=Ppolarized/Ptotal

Stateofpolarization(SOP):

describestheorientation

androtationofthe

polarizedlight

光源和光接收器/分布反馈(DFB)Laser原理：半导体PN结发光＋分布反馈反射腔>>>>激光

光谱：单纵模光谱(Singlelongitudinalmode，SLM)

应用：Highperformancetelecommunicationlaser

Mostexpensive(difficulttomanufacture)Long-haullinks&DWDMsystemsPpeakSMSR光源和光接收器/分布反馈(DFB)LaserKeycharacteristicsMostlyaround1310/1550nmTotalpower3to50mwSpectralwidth10to100MHz(0.08to0.8pm)Sidemodesuppressionratio(SMSR):>50dBCoherencelength1to100mSmallNA(goodcouplingintofiber)光源和光接收器/垂直腔面发光激光器VerticalCavitySurfaceEmittingLasers(VCSEL)DistributedBraggReflector(DBR)MirrorsAlternatinglayersofsemiconductormaterial40to60layers,eachl/4thickBeammatchesopticalacceptanceneedsoffibersmorecloselyKeypropertiesWavelengthrange780to980nm(gigabitethernet)Spectralwidth:<1nmTotalpower:>-10dBmCoherencelength:10cmto10mNumericalaperture:0.2to0.3activen-DBRp-DBROtherLightSourcesWhitelightsourceSpecializedtungstenlightbulbWavelengthrange900to1700nm,Powerdensity0.1to0.4nw/nm(SM),10to25nw/nm(MM)Amplifiedspontaneousemission(ASE)source

“Noise”ofanopticalamplifierwithoutinputsignalWavelengthrange1525to1570nmPowerdensity10to100µw/nmExternalcavitylaserMostcommonfor1550nmband(somefor1310nm)Tunableovermorethan100nm,powerupto10mwSpectrumsimilartoDFBlaser,bandwidth10kHzto1MHzPhotodiodes(光电管）PIN(p-layer,intrinsiclayer,n-layer)Highlylinear,lowdarkcurrentAvalanchephotodiode(APD)Gainuptox100liftsdetectedopticalsignalaboveelectricalnoiseofreceiverBestforhighspeedandhighlysensitivereceiversStrongtemperaturedependenceMaincharacteristicsQuantumefficiency(electrons/photon)DarkcurrentResponsivity(currentvs.L)n+BiasVoltageAPDGainMaterialAspectsSilicon(Si)Leastexpensive

Germanium(Ge)

“Classic”detector

Indiumgalliumarsenide(InGaAs)

HighestspeedWavelengthnm50010001500SiliconGermaniumInGaAsQuantumEfficiency=10.10.51.0Responsivity(A/W)耦合器/分路器

类型*T型耦合器*星型耦合器*定向耦合器*波分复用/解复用器结构*光纤型*微光学器件型主要技术指标*耦合比(CR)*插入损耗(IL)*附加损耗(EL)*方向性（DL)*隔离度（Is)*一致性（U)耦合器/分路器常用耦合器类型

耦合器/分路器●IL(InsertionLoss)IL=-10lgReflectthepowertoeachport.●CR(CouplingRatio)CR=●EL(ExcessLoss)EL=-10lgThetotallossoncoupler

PoutPinPout1Pout1+Pout2Pout1+Pout2Pin耦合器/分路器

DLDL=－10Log(Pj/Pi)

方向性对传输系统的影响*同路异向双信道对传系统

MXN器件发射1接收2发射2接收1耦合器/分路器*同路同向双信道传输系统

*树形网传输系统

发射1发射2接收2接收1发射1XN光纤型_耦合器/分路器*光纤耦合器光纤型_耦合器/分路器光纤定向耦合星型光纤型_耦合器/分路器光纤型_耦合器/分路器光纤分波/合波光纤型_耦合器/分路器原理单模光纤传播光纤型耦合器/分路器_耦合理论Equations：

dR/dz-jdR=-jKS; dS/dz+jdS=-jKRAm=Rexp(-jdz);An=Sexp(jdz)Detuningcoefficient：d=(bn-bm)/2

Couplingcoefficient: K光纤型耦合器/分路器_耦合理论方程解

Modecouplingoftwomixedsignal(ofdifferentwavelength)耦合器/分路器_光纤型波分复用/解复用原理

耦合器/分路器_微光学器件型微器件型耦合器耦合器/分路器_波导型波导型耦合器

隔离器（Isolator）:DefinitionAnisolatorisadevicethatallowslighttopassalongafibreinonedirectionbutnotintheoppositedirection.Isolators/应用Mainapplication:Toprotectlasersandopticalamplifiersfromlightcomingback(whichotherwisecancauseinstabilities)

Insertionloss:Lowloss(0.2to2dB)inforwarddirectionHighlossinreversedirection:

20to40dBsinglestage,40to80dBdualstage)

Returnloss:Morethan60dBwithoutconnectorsSimpleIsolator/原理Isolators/工作原理隔离器工作原理

环行器（Circulator）:DefinitionLightenteringatanyparticularport(sayport1)travelsaroundthecirculatorandexitsatthenextport(sayport2).Lightenteringatport2leavesatport3andsoon.Circulators/应用Circulator&chirpedFGBconfiguredtocompensateCDOpticalcrystaltechnologysimilartoisolatorsInsertionloss0.3to1.5dB,isolation20to40dB

Typicalconfiguration:3portdevicePort1 -> Port2Port2 -> Port3Port3 -> Port1Fast

lSlow

l环形器应用：Add/DropNodesFilterreflectsliAddliAdd/DropDielectricthin-filmfilterdesignCirculatorwithFBGdesignCommonPassbandDropliFilterCharacteristicsli-1lili+1PassbandCrosstalkCrosstalkPassbandInsertionlossRippleWavelengths

(peak,center,edges)Bandwidths

(0.5dB,3dB,..)PolarizationdependenceStopbandCrosstalkrejectionBandwidths

(20dB,40dB,..)DielectricFiltersThin-filmcavitiesAlternatingdielectricthin-filmlayerswithdifferentrefractiveindexMultiplereflectionscauseconstructive&destructiveinterferenceVarietyoffiltershapesandbandwidths(0.1to10nm)Insertionloss0.2to2dB,stopbandrejection30to50dBLayersSubstrateIncomingSpectrumReflectedSpectrumTransmittedSpectrum1535nm1555nm0dB30dBTunableFabry-P