雙異質(zhì)結(jié)結(jié)構(gòu)提高了半導(dǎo)體光源的量子效率課件

Fiber-OpticCommunicationTechnologyChapter3OpticalTransmittersFiber-OpticCommunicationTech2023/10/7OE,HUST2Chapter3.OpticalTransmittersIntroductionBasicconceptsSemiconductorlasers(LaserDiode)LaserCharacteristicsLight-EmittingDiodes(LED)TransmitterDesign2023/10/6OE,HUST2Chapter3.2023/10/7OE,HUST3Opticaltransmitter：光發(fā)射機(jī)LED:發(fā)光二極管LD：激光二極管Spontaneousemission：自發(fā)輻射Stimulatedemission：受激發(fā)射Stimulatedabsorption：受激吸收Boltzmanstatistics：玻爾茲曼統(tǒng)計分布Thermalequilibrium：熱平衡Spectraldensity：光譜密度Populationinversion：粒子數(shù)反轉(zhuǎn)Fermi-Diracdistribution：費(fèi)米狄拉克分布Conductionband：導(dǎo)帶Valenceband：價帶Forward-biased：正向偏置Junction：結(jié)Fermilevel：費(fèi)米能級Bandgap：帶隙Heavydoping：重?fù)诫sHomojunction：同質(zhì)結(jié)Heterojunction：異質(zhì)結(jié)Doubleheterostructure：雙異質(zhì)結(jié)Electron-holerecombination：電子空穴復(fù)合Claddinglayer：包層Augerrecombination：俄歇復(fù)合Kineticenergy：動能Nonradiativerecombination：非輻射復(fù)合Surfacerecombination：表面復(fù)合Internalquantumefficiency：內(nèi)量子效率Directbandgap：直接帶隙Indirectbandgap：非直接帶隙Carrierlifetime：載流子壽命Latticeconstant：晶格常數(shù)Ternaryandquaternarycompound：三元系和四元系化合物Substrate:襯底LPE：液相外延VPE：汽相外延MBE：分子束外延MOCVD：改進(jìn)的化學(xué)汽相沉積MQW:多量子阱2023/10/6OE,HUST3Opticaltran2023/10/7OE,HUST4Electron-holepairs電子空穴對Externalquantumefficiency外量子效率Fresneltransmissivity菲涅耳透射率Lambertiansource朗伯光源Power-conversionefficiency功率轉(zhuǎn)換效率Wall-plugefficiency電光轉(zhuǎn)換效率Responsivity響應(yīng)度Rateequation速率方程Surface-emitting表面發(fā)射Beamdivergence光束發(fā)散Edge-emitting邊發(fā)射Resonantcavity諧振腔Gaincoefficient增益系數(shù)Differentialgain微分增益Laserthreshold激光閾值Thresholdcurrent閾值電流Groupindex群折射率Externalcavity外腔Broadarea寬面Stripegeometry條形Diffusion擴(kuò)散Index-guided折射率導(dǎo)引Ridgewaveguidelaser脊波導(dǎo)激光器Buriedheterostructure掩埋異質(zhì)結(jié)Lateral側(cè)向Transverse橫向SLM:SingleLongitudinalmode單縱模MSR:Modesuppressionratio模式抑制比DFB:DistributedFeedback分布式反饋Braggdiffraction布拉格衍射Braggcondition布拉格條件DBR:distributedBraggreflector分布式布拉格反射器Phase-shiftedDFBlaser相移DFB激光器Gaincoupled增益耦合Coupledcavity耦合腔2023/10/6OE,HUST4Electron-hol2023/10/7OE,HUST5Superstructuregrating超結(jié)構(gòu)光柵VCSEL:verticalcavitysurface-emittinglasers垂直腔表面發(fā)射激光器Photonlifetime光子壽命Spontaneous-emissionfactor自發(fā)輻射因子Characteristicstemperature特征溫度Slopeefficiency斜率效率Differentialquantumefficiency微分量子效率Linewidthenhancementfactor線寬加強(qiáng)因子2023/10/6OE,HUST5Superstructu2023/10/7OE,HUST63.1Introduction3.1.1ComponentsofOpticalTransmittersBinarytosingleCoding/linecodingModulatorOpticalSourceDrivingCircuitPCMChannelcouplerOpticalsignaloutput2023/10/6OE,HUST63.1Introduc2023/10/7OE,HUST7BiasedcurrentModulationcurrent(≥10Gb/s)ModulationcurrentBiasedcurrent(≤2.5Gb/s)(a)DirectModulation(b)ExternalModulation2023/10/6OE,HUST7Biasedcurre2023/10/7OE,HUST81.stability:power&wavelength2.reliability:>25years(PouttoPout/2)3.smallemissiveareacompatiblewithfibercoredimensions4.rightwavelengthrange0.85μm:GaAlAs/GaAs1.31μm,1.55μm:InP/InGaAsP5.narrowlinewidth→dispersion,phasenoise6.directmodulation!?7.highefficiency&lowthreshold:MQW-LD,Ith~10mA3.1.2RequirementsforOpticalSourceMQWDFBLD2023/10/6OE,HUST81.stability2023/10/7OE,HUST9Chapter3.OpticalTransmittersIntroductionBasicconceptsSemiconductorlasers(LaserDiodes)LaserCharacteristicsLight-EmittingDiodes(LED)TransmitterDesign2023/10/6OE,HUST9Chapter3.2023/10/7OE,HUST103.2.1Threefundamentaltransitionprocesses 1.SpontaneousEmission→LED 2.StimulatedEmission→LD,SOA 3.StimulatedAbsorption→PIN/APD

3.2BasicConceptsLightEmission2023/10/6OE,HUST103.2.1Three2023/10/7OE,HUST113.2.2EmissionandAbsorptionRatesE2N2N1E1:spectraldensityoftheelectromagneticenergyInthermalequilibrium,accordingtoBoltzmannStatistics:kB:BoltzmannConstantT:AbsoluteTemperatureAccordingtoPlanck’sformula:2023/10/6OE,HUST113.2.2Emiss2023/10/7OE,HUST12visibleornear-infraredregion,roomtemperature,thermalsourcesN2>N1,Rstim>Rabs(populationinversion)thermalequilibrium laseroperation ?Operationconditionforlaser:Externalpumpingsourceisneeded:injectioncurrent,pumpinglightetc.2023/10/6OE,HUST12visibleor2023/10/7OE,HUST13原子是由原子核和繞原子核旋轉(zhuǎn)的電子組成。最里層的電子距原子核最近，受原子核束縛最強(qiáng)，能量最低（包括電子的動能和勢能）。越外層的電子受原子束縛越弱，能量越高；電子只能處于特定的能級之上；能級圖用一系列高低不同的水平橫線來表示電子所能取的確定能量；原子中的電子通過和外界交換能量的方式發(fā)生能級的躍遷——熱躍遷和光躍遷。Energybandsinsemiconductorconductionband&valenceband2023/10/6OE,HUST13原子是由原子核和繞原子2023/10/7OE,HUST14實(shí)際物體是由大量原子構(gòu)成的，每一原子的電子特別是外層電子除受本身原子的勢場作用外，還受到相鄰原子的作用。半導(dǎo)體材料中原子在共價鍵的作用下形成緊密相間、周期排列的晶格結(jié)構(gòu)。電子能級受晶格作用發(fā)生分裂而形成能帶；Si2023/10/6OE,HUST14實(shí)際物體是由大量原子構(gòu)2023/10/7OE,HUST15價帶：由共價鍵束縛的價電子所占據(jù)的能帶為價帶；導(dǎo)帶：由自由電子占據(jù)的能帶為導(dǎo)帶，導(dǎo)帶位于價帶之上；禁帶：導(dǎo)帶和價帶之間被寬度為Eg的帶隙分開，稱為禁帶；絕緣體：Eg～7eV，電子不容易躍遷到導(dǎo)帶；半導(dǎo)體：Eg～1eV，電子容易躍遷到導(dǎo)帶；導(dǎo)體：Eg～0eV，沒有帶隙。2023/10/6OE,HUST15價帶：由共價鍵束縛的價2023/10/7OE,HUST16EnergybandsinsemiconductorrecombinationbetweenelectronsandholesTheoccupationprobabilityforelectronsintheconductionandvalencebandsisgivenbytheFermi-Diracdistributions:Efc,EfvaretheFermilevelsinconductionbandandvalencebandrespectively2023/10/6OE,HUST16Energyband2023/10/7OE,HUST17:jointdensityofstates,whichdescribethenumberofstatesperunitvolumeperunitenergyrangeEg:bandgapmr:reducedmassmc,mv:effectivemassesofelectrons&holesinconductionandvalencebands,respectively2023/10/6OE,HUST17:jointde2023/10/7OE,HUST18population-inversioncondition:

inthermalequilibrium:pumpingenergyintosemiconductorbyinjectingcurrent

Togetlaseroutput,2023/10/6OE,HUST18population-2023/10/7OE,HUST191.

TypeofsemiconductorIntrinsicsemiconductor:undoped,Fermilevelislyinginthemiddleofthebandgapn-typesemiconductor:Fermilevelmovestowardtheconductionbandasthedopantconcentrationincreasesp-typesemiconductor:Fermilevelmovestowardthevalencebandasthedopantconcentrationincreases3.2.3p-njunctions2023/10/6OE,HUST191.Typeof2023/10/7OE,HUST20

n-typeIntrinsic

p-typeforwardbiasedp-typesemiconductor

&n-typesemiconductor2023/10/6OE,HUST20n-typeIntr2023/10/7OE,HUST21(a)inthermalequilibrium(b)underforwardbiased2.p-njunctionsunderforwardbiased:built-inelectricfieldisreduceddiffusionofelectronsandholesacrossthejunctionelectronsandholesarepresentsimultaneouslyindepletionregiongeneratelightthroughspontaneousemissionorstimulatedemissioninthermalequilibrium:

theFermilevelmustbecontinuousacrossthep–njunctionachievedthroughdiffusionofelectronsandholesacrossthejunction.2023/10/6OE,HUST21(a)inther2023/10/7OE,HUST22Homojunction:equalbandgapsthesamesemiconductormaterialwideregionforelectron-holerecombinationdifficulttorealizehighcarrierdensitiesHeterojunction:differentbandgapsDouble-heterojunction:

sandwichingathinlayerbetweenthep-typeandn-typelayerssuchthatthebandgapofthesandwicheslayerissmallerthanthelayersurroundingit.4.Homojunction&heterojunction2023/10/6OE,HUST22Homojunctio2023/10/7OE,HUST232023/10/6OE,HUST232023/10/7OE,HUST24Activelayer:lightisgeneratedinsideitasaresultofelectron-holerecombinationhigherdensityofcarriers→higherindex→waveguide(1D)Heterojunction:confinementofcarriers&opticalfield0.85μm:cladding/active:GaAlAs/GaAs1.31μm,1.55μm:cladding/active:InP/InGaAsP2023/10/6OE,HUST24Activelaye2023/10/7OE,HUST251.electron-holerecombination3.2.4NonradiativeRecombinationTrapofdefectsSurfacerecombinationAugerNonradiativerecombination2023/10/6OE,HUST251.electron2023/10/7OE,HUST262.internalquantumefficiencyRrr:radiativerecombinationrateRnr:nonradiativerecombinationrateRtot:totalrecombinationrateτ:recombinationtimeNonradiativerecombination,especiallyAugerrecombination(temperaturedependent)isharmfultodevices!positivefeedback

2023/10/6OE,HUST262.internal2023/10/7OE,HUST27E0E0k1k2(1)direct-bandgap(GaAs,InP)(2)indirect-bandgap(Si,Ge)3.carrierlifetimeA:defects&trapsB:spontaneousradiationC:Auger2023/10/6OE,HUST27E0E0k1k2(1)2023/10/7OE,HUST28Qualityoftheheterojunctioninterfacedependsonthelatticeconstantofthetwomaterials.(matching!)3.2.5SemiconductorMaterialsternarycompound2023/10/6OE,HUST28Qualit2023/10/7OE,HUST29quaternarycompound0.85μm:GaAlAs/GaAs(cladding/active)

1.31μm,1.55μm:InP/InGaAsP(cladding/active)2023/10/6OE,HUST29quaternary2023/10/7OE,HUST302023/10/6OE,HUST302023/10/7OE,HUST31Chapter3.OpticalTransmittersIntroductionBasicconceptsSemiconductorlasers(LaserDiodes)LaserCharacteristicsLight-EmittingDiodes(LED)TransmitterDesign2023/10/6OE,HUST31Chapter3.2023/10/7OE,HUST323.3Semiconductorlasers(LaserDiodes)Advantagesofstimulatedemissioncomparedwithspontaneousemissionofsemiconductormaterialsemittinghighpower(to100mW)narrowangularspreadnarrowspectralwidthdirectmodulationathighfrequency(to10GHz,becauseissmall)2023/10/6OE,HUST323.3Semicon2023/10/7OE,HUST33ComponentsofSemiconductorLasers2023/10/6OE,HUST33Components2023/10/7OE,HUST34z=0z=LInjectioncurrentGainmediumResonantcavityResonantcavityModeloflaser2023/10/6OE,HUST34z=0z=LInjec2023/10/7OE,HUST353.3.1OpticalGainPeakgainofmedium:

when :differentialgain(gaincrosssection) :injectioncarrierdensity :transparentcarrierdensity:thresholdcarrierdensityNTisequaltoNth?2023/10/6OE,HUST353.3.1Optic2023/10/7OE,HUST36Figure3.9:(a)Gainspectrumofa1.3-μmInGaAsPlaseratseveralcarrierdensitiesN.(b)Variationofpeakgaingp

withN.Thedashedlineshowsthequalityofalinearfitinthehighgainregion.Blueorredshiftingofpeakwavelengthwheninjectedcurrentincreases?2023/10/6OE,HUST36Figure3.9:2023/10/7OE,HUST373.3.2FeedbackandLaserThresholdFeedbackR1R2n0=1n2023/10/6OE,HUST373.3.2Feedb2023/10/7OE,HUST38Threshold2023/10/6OE,HUST38Threshold2023/10/7OE,HUST39AmplitudeconditionPhaseconditionspacingofoscillatingfrequencyoscillatingfrequencythresholdgainMLM2023/10/6OE,HUST39Amplitudec2023/10/7OE,HUST403.3.3LDStructuresBroad-areaLDFigure3.12:Abroad-areasemiconductorlaser.Theactivelayer(hatchedregion)issandwichedbetweenp-typeandn-typecladdinglayersofahigher-bandgapmaterial.light-confinementmechanisminthedirectionperpendiculartothejunctionplaneintroducedbydoubleheterostructure

XYdistributioninnearfield2023/10/6OE,HUST403.3.3LDSt2023/10/7OE,HUST41nosuchlight-confinementmechanisminthelateraldirectionparalleltothejunctionplane.thelightgeneratedspreadsovertheentirewidthofthelaser.relativelyhighthresholdcurrentandaspatialpatternthatishighlyellipticalandthatchangesinanuncontrollablemannerwiththecurrent.Howaboutspatialmodeinwaveguideanddistributioninfarfield?2023/10/6OE,HUST41nosuchlig2023/10/7OE,HUST42Gain-guidedsemiconductorlasersFigure3.13:Crosssectionoftwostripe-geometrylaserstructuresusedtodesigngain-guidedsemiconductorlasersandreferredtoas(a)oxidestripeand(b)junctionstripe.Stripelasers

XY2023/10/6OE,HUST42Gain-guide2023/10/7OE,HUST43solvethelight-confinementproblembylimitingcurrentinjectionoveranarrowstripe.thespotsizeisstillnotstableasthelaserpowerisincreased.Injectioncurrentinducedindexvariety!2023/10/6OE,HUST43solvethel2023/10/7OE,HUST44Index-guidedsemiconductorlasersFigure3.14:Crosssectionoftwoindex-guidedsemiconductorlasers:(a)ridge-waveguidestructureforweakindexguiding;(b)etched-mesaburiedheterostructureforstrongindexguiding.

XY2023/10/6OE,HUST44Index-guid2023/10/7OE,HUST45Multi-Quantum-WellLD有源區(qū)厚度薄1~10nm周期結(jié)構(gòu)，將窄帶隙的很薄的有源區(qū)夾在寬帶隙的半導(dǎo)體材料之間，形成勢能阱多個勢能阱--多量子阱（MQW）2023/10/6OE,HUST45Multi-Quant2023/10/7OE,HUST46homojunctionDoubleheterostructureStripegeometryMulti-quantum-wellRelativelystrongerconfinementofinjectedcarriersandoutputphotons,thuslowerthresholdcurrent,andhigherslopeefficiency!2023/10/6OE,HUST46homojunctio2023/10/7OE,HUST473.3.4ControlofLongitudinalModesSideModeSuppressionRatio(SMSR):orMLMLossSLM2023/10/6OE,HUST473.3.4Contr2023/10/7OE,HUST48DistributedFeedback(DFB)Lasers

相位光柵在波導(dǎo)中產(chǎn)生折射率的周期性變化，使正反向傳播的行波產(chǎn)生耦合。當(dāng)光波長滿足布拉格條件時，耦合達(dá)到最大。在布拉格條件下，某一入射波長幾乎被全反射，光柵起到了對波長選擇性反射的作用。光柵周期滿足：2023/10/6OE,HUST48Distributed2023/10/7OE,HUST49Coupled-cavitylaserFigure3.18:Coupled-cavitylaserstructures(a)external-cavitylaser;(b)cleaved-coupledcavitylaser;(c)multisectionDBRlaser.2023/10/6OE,HUST49Coupled-cav2023/10/7OE,HUST50

增益介質(zhì)反射鏡準(zhǔn)直透鏡透鏡光纖增透膜濾光片高反膜λcExternalcavitylaser2023/10/6OE,HUST50增益介質(zhì)反2023/10/7OE,HUST51SampledGratingDBRLaserDBR:distributedBraggreflector2023/10/6OE,HUST51SampledGra2023/10/7OE,HUST52Cleaved-coupledcavitylaser2023/10/6OE,HUST52Cleaved-cou2023/10/7OE,HUST53VCSEL2023/10/6OE,HUST53VCSEL2023/10/7OE,HUST54思考題1.現(xiàn)有半導(dǎo)體激光器的F-P諧振腔，長度為400

m，材料折射率為3.5，諧振腔兩端面一端鍍有增反射膜，反射率為90％，另一端沒有鍍膜。現(xiàn)有半導(dǎo)體激光器工作在1550nm附近，要求諧振腔諧振的閾值增益系數(shù)小于75cm－1，請問：如何選擇半導(dǎo)體材料和組分？諧振腔內(nèi)部損耗系數(shù)應(yīng)滿足什么條件？2023/10/6OE,HUST54思考題1.現(xiàn)有半導(dǎo)體2023/10/7OE,HUST55Chapter3.OpticalTransmittersIntroductionBasicconceptsSemiconductorlasers(LaserDiodes)LaserCharacteristicsLight-EmittingDiodes(LED)TransmitterDesign2023/10/6OE,HUST55Chapter3.2023/10/7OE,HUST563.4LaserCharacteristics

3.4.1CWCharacteristicsForaSLMlaser,therateequations:P,N:numberofphotons&carriersNetrateofstimulatedemission—opticalgain:g:peakgainofmaterial:gaincrosssection,ordifferentialgain.Photonlifetime:2023/10/6OE,HUST563.4LaserC2023/10/7OE,HUST57Thresholdofcurrent&carrierForI>Ith(R1=R2)CWoperation:2023/10/6OE,HUST57Thresholdo2023/10/7OE,HUST58ThresholdofP-IcurvesSpontaneousemissionStimulatedemissionI0:constantT0:characteristictemperatureGaAs:T0=120K,InGaAsP:T0=50~70KP-IcurvesBendingofP-Icurves

Rnr:mainlydependingonAugerrecombinationinInGaAsPLDsSolution:built-inthermoelectriccoolerisusedtodealwithtemperaturesensitivitiesofInGaAsPLDs2023/10/6OE,HUST58Thresholdo2023/10/7OE,HUST59EfficienciesInternalquantumefficiency:Slopeefficiency:Differentialquantumefficiency:Externalquantumefficiency:wall-plugefficiency:2023/10/6OE,HUST59Efficiencie2023/10/7OE,HUST603.4.2Small-SignalModulationsmall-signalmodulation:Frequencyresponse2023/10/6OE,HUST603.4.2Small2023/10/7OE,HUST61Figure3.21:Modulationresponseofalaserasafunctionofmodulationfrequencyatseveralbiaslevels.ModulationbandwidththeefficiencyisreducedwhenthemodulationfrequencyexceedsΩR

byalargeamount.2023/10/6OE,HUST61Figure3.212023/10/7OE,HUST623.4.3Large-SignalModulationExternalmodulationforhighspeedtransmission!Frequencychirp

leadingedge:modefrequencyshiftstowardtheblue

sidetrailingedge:modefrequencyshiftstowardtheredside:amplitude-phasecouplingparameter,ex.bulkmaterial:4~8;MQW:~32023/10/6OE,HUST623.4.3Large2023/10/7OE,HUST63Electro-opticalDelay&RelaxationOscillation

Pre-biasedtoreducedelaytime!請參見江劍平編著的《半導(dǎo)體激光器》2023/10/6OE,HUST63Electro-opt2023/10/7OE,HUST64Patterneffect

TBIP“11”“11”當(dāng)電光延遲時間與電調(diào)制速率對應(yīng)的的碼元持續(xù)時間相近時，會使“0”碼后的第一個“1”碼脈沖寬度變窄，幅度變小，嚴(yán)重時使單個“1”碼丟失，這種現(xiàn)象即“碼型效應(yīng)”。連“0”數(shù)越多，調(diào)制速率越高，該效應(yīng)越明顯。用適當(dāng)?shù)摹斑^調(diào)制”補(bǔ)償，可以消除碼型效應(yīng)。2023/10/6OE,HUST64Patterneff2023/10/7OE,HUST65Self-pulsation不同于張弛振蕩，沒有阻尼，脈動頻率范圍為0.2~4GHz容易發(fā)生在閾值附近和P-I特性的扭曲區(qū)造成自脈動的機(jī)理涉及量子噪聲效應(yīng)、有源區(qū)的缺陷及溫度感應(yīng)的變化等因素抑制這種現(xiàn)象主要靠控制材料的質(zhì)量，盡量減少有源區(qū)的缺陷。Operatedfarfromkinkzone!OPIPI2023/10/6OE,HUST65Self-pulsat2023/10/7OE,HUST66Simulation1-Directmodulation2023/10/6OE,HUST66Simulation2023/10/7OE,HUST67Simulation2-Externalmodulation

2023/10/6OE,HUST67Simulation2023/10/7OE,HUST68Ib&ImLD偏置電流的選擇合適與否直接影響激光器的高速調(diào)制輸出特性。加大直流偏置，使其接近閾值，可以減小電光延遲時間，也可使張馳振蕩得到一定程度的抑制。當(dāng)激光器偏置在閾值附近時，較小的調(diào)制電流就能得到足夠高的輸出光脈沖，調(diào)制效率較高。而且由于偏置電流與最大電流相差不大，可以大大減小碼型效應(yīng)和結(jié)發(fā)熱效應(yīng)的不良影響。過大的偏置電流會使消光比惡化，影響接收機(jī)靈敏度。激光器恰好偏置在閾值時，散粒噪聲會增強(qiáng)，直接影響信號的信噪比。2023/10/6OE,HUST68Ib&ImLD偏置2023/10/7OE,HUST69Chapter3.OpticalTransmittersIntroductionBasicconceptsSemiconductorlasers(LaserDiodes)LaserCharacteristicsLight-EmittingDiodes(LED)TransmitterDesign2023/10/6OE,HUST69Chapter3.2023/10/7OE,HUST703.5.1Power-CurrentCharacteristics3.5Light-EmittingDiodes(LEDs)aforward-biasedp-njunction→spontaneousemission→LED2023/10/6OE,HUST703.5Light-E2023/10/7OE,HUST712023/10/6OE,HUST712023/10/7OE,HUST72Power-conversionefficiency(wall-plugefficiency)2023/10/6OE,HUST72Power-conve2023/10/7OE,HUST73P-ICurveResponsivity:(1)responsivityremainsconstantwhenIissmall(2)bendingofP-Icurve:(3)nothreshold

2023/10/6OE,HUST73P-ICurveRe2023/10/7OE,HUST743.5.2LEDSpectrumanapproximateexpression:LEDsaresuitableforLANwithlowbitrate&shortdistance!2023/10/6OE,HUST743.5.2LEDS2023/10/7OE,HUST75Figure3.7:(b)spectrumoftheemittedlightforatypical1.3-μmLED.超寬帶光源白光LED2023/10/6OE,HUST75Figure3.7:2023/10/7OE,HUST762023/10/6OE,HUST762023/10/7OE,HUST773.5.3ModulationResponseRateequation::injectioncarrier:carrierofrecombination(nonradiative&spontaneousemission)Sinusoidalmodulation:Ib:biascurrentIm:modulationcurrentωm:modulationfrequency2023/10/6OE,HUST773.5.3Modul2023/10/7OE,HUST78Sincemodulatedpowerisrelatedtolinearly2023/10/6OE,HUST78Sincemodul2023/10/7OE,HUST793.5.4LEDStructures(a)(b)(a)surface-emittingLED(b)edge-emittingLED2023/10/6OE,HUST793.5.4LEDS2023/10/7OE,HUST80思考題1.以下論述正確的是：（）A、非輻射復(fù)合會影響發(fā)光器件的發(fā)光效率；B、正向偏置的PN結(jié)中導(dǎo)帶和價帶的準(zhǔn)費(fèi)米能級趨于一致；C、半導(dǎo)體材料要發(fā)光，必須實(shí)現(xiàn)粒子數(shù)的反轉(zhuǎn)；D、LED中最初的光子來源于內(nèi)部的自發(fā)輻射；E、電子與空穴復(fù)合不一定產(chǎn)生光子；F、雙異質(zhì)結(jié)結(jié)構(gòu)提高了半導(dǎo)體光源的量子效率；G、工作于1.55

m處的半導(dǎo)體光源有源層材料為InP；

H、溫度升高發(fā)光器件的發(fā)光效率會下降；

I、間接帶隙半導(dǎo)體材料中非輻射復(fù)合效率高于輻射復(fù)合效率，不適合用作光源材料。2023/10/6OE,HUST80思考題1.以下論述正2023/10/7OE,HUST811.以下論述正確的是：（）

A、非輻射復(fù)合會影響發(fā)光器件的發(fā)光效率；

B、正向偏置的PN結(jié)中導(dǎo)帶和價帶的準(zhǔn)費(fèi)米能級趨于一致；C、半導(dǎo)體材料要發(fā)光，必須實(shí)現(xiàn)粒子數(shù)的反轉(zhuǎn)；

D、LED中最初的光子來源于內(nèi)部的自發(fā)輻射；

E、電子與空穴復(fù)合不一定產(chǎn)生光子；

F、雙異質(zhì)結(jié)結(jié)構(gòu)提高了半導(dǎo)體光源的量子效率；G、工作于1.55

m處的半導(dǎo)體光源有源層材料為InP；

H、溫度升高發(fā)光器件的發(fā)光效率會下降；

I、間接帶隙半導(dǎo)體材料中非輻射復(fù)合效率高于輻射復(fù)合效率，

不適合用作光源材料。2023/10/6OE,HUST811.以下論述正確的是2023/10/7OE,HUST82A、LD的激射波長一定是自發(fā)輻射的峰值波長；B、條形激光器中也存在雙異質(zhì)結(jié)結(jié)構(gòu)；C、雙異質(zhì)結(jié)中對載流子的限制作用是因?yàn)榇嬖趦?nèi)建折射率波導(dǎo)；D、通過選擇合適的組分x和y，基于In1-xGaxAsyP1-y的半導(dǎo)體光源可設(shè)計工作于0.85

m處；E、LD有諧振腔，而LED沒有；F、LD的P-I曲線有閾值，而LED的P-I曲線沒有閾值；G、LD和SOA中最初的光子均來源于自發(fā)輻射；H、激光器的小信號調(diào)制帶寬會隨著偏置電流的增加而增大；I、偏置電流選擇合理可適當(dāng)減小張馳振蕩和電光延時效應(yīng)的影響；J、單縱模LD用作光源時，色散容限大。

2.以下關(guān)于半導(dǎo)體材料和發(fā)光機(jī)理論述錯誤的是：2023/10/6OE,HUST822.以下關(guān)于半導(dǎo)體2023/10/7OE,HUST83

A、LD的激射波長一定是自發(fā)輻射的峰值波長；B、條形激光器中也存在雙異質(zhì)結(jié)結(jié)構(gòu)；

C、雙異質(zhì)結(jié)中對載流子的限制作用是因?yàn)榇嬖趦?nèi)建折射率波導(dǎo)；

D、通過選擇合適的組分x和y，基于In1-xGaxAsyP1-y的半導(dǎo)體光源可設(shè)計工作于0.85

m處；E、LD有諧振腔，而LED沒有；F、LD的P-I曲線有閾值，而LED的P-I曲線沒有閾值；

G、LD和SOA中最初的光子均來源于自發(fā)輻射；H、激光器的小信號調(diào)制帶寬會