6.973Semiconductor Optoelectronics6.973 Semiconductor OptoelectronicsLecture 1: Course OverviewRajeev J. RamOffice: 36-491Telephone:X3-4182Email: [email protected] Optoelectronics•Background: p-n junctions•Photodetectors•Modulators•Optical amplifiers•Semiconductor lasers•Heterostructure materials•DFB and VCSEL resonators•Modulation•SystemsSyllabusBasic conceptsAdvancedconcepts6.973Semiconductor OptoelectronicsOutline for Lecture 1Outline for Lecture 1• Applications of Optoelectronic Devices• Overview of Devices• Course Administration6.973Semiconductor OptoelectronicsOptical Devices Optical Devices Passive Optical Devices• Waveguides•Optical DiskActive Optical Devices•LEDS• Semiconductor lasers• DetectorsDVD player6.973Semiconductor OptoelectronicsPassive Optical DevicesPassive Optical DevicesWaveguidesWaveguidesTotal internal reflectionCorning6.973Semiconductor OptoelectronicsPremium Optical (Toslink) cables are used for digital audio connectionsFeatures:- Application light wavelength 655 + or - 30 nm- Attenuation less than or equal to 0.25 dB per meter- Bend Radius greater than or equal to 17 mm- Connection loss less than or equal to 0.5 dBWaveguides for DVD PlayersWaveguides for DVD PlayersPlastic Optical FiberPlastic Optical FiberPMMA (polymethyl methacrylate) core6.973Semiconductor Optoelectronics7.5 miles of trackDVD DisksDVD Disks‘‘NanostructuredNanostructuredMaterial’Material’120 nm deep pits by injection molding6.973Semiconductor OptoelectronicsActive Devices for DVD PlayersActive Devices for DVD PlayersLaserstrained QW at 655 nmDetector6.973Semiconductor OptoelectronicsDevices for Optical CommunicationsDevices for Optical Communications6.973Semiconductor OptoelectronicsExample of Metro WDM RxTxABCDA -123B1-45C24-6D 356-Interconnect tableLogical mesh6 transmitter wavelengths required for 4 nodes.OADM Node configurationTx Tx TxRx Rx Rx amplifiersamplifiersNode ARx TxRx Tx1,2,3,4,4,5,5,6,6 2,3,4,5,6,6 3,5,6Rx:1,2,3,4,4,5,5,6,6 Rx:1,1,2,2,3,4,4,5,6Rx TxRx:1,2,2,3,3,4,5,6,6Rx TxRx:1,1,2,3,3,4,5,5,6Node B Node C Node D1,2,3 1,1,2,3,4,5 1,1,2,2,3,4,4,5,6MetroCO/POPCO/POPCO/POPCO/POPCO/POPCO/POPCO/POPCO/POPAccessADMADMADMADMLocal LoopCoreSan FranciscoSeattleSubmarineNetworkBostonChicagoMetro6.973Semiconductor OptoelectronicsPutting It All Together: OADM NodePutting It All Together: OADM NodeR-TpVTransmit & Receive TranspondersClient IP,ATM,SDH/SONET,PDHTransmit & Receive TranspondersClient IP,ATM,SDH/SONET,PDHPre-ampEastPre-ampWestWDMPower ampWestPower ampEastControlChannelWDMWDMWDMMUXTrafficTraffic......DEMUXR-TpRtpRtpTpTpTp TpMUXGain block•EDFAmplifier•Pump lasers•Detectors•980/1550 MUX•Isolators•Gain equalizersMultiplexers•AWG (‘Prism’)•Thermoelectrics•AttenuatorsTransceivers•EA modulator +DFB•Thermoelectrics•Isolators•Detectors•Laser Driver•Receiver Amps6.973Semiconductor OptoelectronicsOutline for Lecture 1Outline for Lecture 1• Applications of Optoelectronic Devices• Overview of Devices• Course Administration6.973Semiconductor OptoelectronicsBackground: p-n junctionsLarge electric fields•p-i-n photodetector•modulators0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9-6-5.5-5-4.5-4-3.5-3-2.5-2Position (um)E (eV)NA= 1017ND= 1017Unbiased0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9-4.5-4-3.5-3-2.5-2-1.5Position (um)E (eV)BiasedInjection of high carrier density•diode laser•optical amplifier•tunable filters•variable optical attenuatorAbsorptionEmission6.973Semiconductor OptoelectronicsPhotodetectorsPI N6.973Semiconductor Optoelectronics00.20.40.60.811.210 100 10003 dB Bandwidth (GHz)Equivalent Device Slope Efficiency at λ = 1300 nm (A/W)Fujitsu, 1991BT&D, 1991UCSB / Colorado State, 1993UCLA / JPL / Lucent, 1996AT&T Bell Labs, 1986NTT, 1991NTT, 1994Ortel, 1996NTT, 1992UCSD, 1993UCSB, 1995Wq λAh cTheoretical Maximum = –––– = 1.05 ––Gray line indicates maximum available at any given frequencyUCSB, 1997AT&T Bell Labs, 1986 UCSD / Fermionics, 1996Thomson-CSF, 1997AT&T Bell Labs, 1986UCSD, 1992UCSB, 1995NTT, 1991NTT, 1997PIN (1500 nm)Waveguide (830 nm)Waveguide (1000 nm)Waveguide (1300 nm)Waveguide (1550 nm)MSM/Schottky (600 nm)PIN – 1300 nmPIN – 1550 nmWaveguide PIN – 800 nmWaveguide PIN – 1300 nmWaveguide PIN – 1550 nmThomson-CSF, 1996Ortel, 1994UCSB / Colorado State, 1995NTT, 1997Courtesy of Charles Cox, PSIPhotodetectors6.973Semiconductor OptoelectronicsElectro-absorption ModulatorsFast Electrically Controlled ShuttersE = 0 E = 0Stark shift in quantum well6.973Semiconductor OptoelectronicsElectro-absorption ModulatorsE = 0 E = 0Stark shift in quantum wellApplied voltageElectric field at quantum wellChange in energy level (DOS)Change in e-h overlap (peak abs)Electrostatics of pn junctions2ndorder perturbation theory1storder perturbation theory6.973Semiconductor OptoelectronicsBackground: p-n junctionsLarge electric fields•p-i-n photodetector•modulators0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9-6-5.5-5-4.5-4-3.5-3-2.5-2Position (um)E (eV)NA= 1017ND= 1017Unbiased0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9-4.5-4-3.5-3-2.5-2-1.5Position (um)E (eV)BiasedInjection of high carrier density•diode laser•optical amplifier•tunable filters•variable optical attenuatorAbsorptionEmission6.973Semiconductor OptoelectronicsOptical Amplifiers6.973Semiconductor OptoelectronicsSemiconductor Lasers()gzoeIzI =RIIir=RIIir=Fabry-Perot Resonator6.973Semiconductor Optoelectronicscurrentradiative non-radiativeQW captureleakageinternal lossmirror lossfiber coupledabove thresholdbelow thresholdphotonsoutput power (mW)current (mA)Semiconductor Lasersthreshold6.973Semiconductor OptoelectronicsHeterostructure Materialsundoped8x1017P- dopedn-doped8x1017InP substrateInP ridgeelectronsholesMinimum of 3 materials for good optical and electrical confinementMinimum:Quantum wellQW barrierWaveguide claddingTypical:Quantum wellQW barrierWaveguide core (SCH)Waveguide claddingElectrical contact layeroptical mode6.973Semiconductor Optoelectronics• Advantages– More efficient, higher material gain, lower threshold• Concentration of carriers near band edge – Less thermal dependence, spectral broadeningLedenstov et al. Quantum-dot heterostructure lasers. JSTQE, May 2000.Quantum Confinement in Semiconductor LasersQuantum Confinement in Semiconductor Lasers6.973Semiconductor OptoelectronicsThe World of Semiconducting MaterialsThe World of Semiconducting MaterialsInP850 nm980