光纤通信系统中的光接收与光发送器件.pdf

光接收器件基本原理 光接收器件发展趋势 光发送器件基本原理 光发送器件发展趋势光纤通信系统中光接收发送器件的应用Raman amplification unitModulator 2Modulator3Modulator 1Laser 2Receiver 3Receiver 1Dispersion compensation systemDispersion compensation systemEDFA Erbiunvdoped liber amplrtierReceiver n-8&君9。Modulator n光纤通信系统的光接收机光通信系统对光接收器件的要求更长的工作波长，更高的扪z号度 更快的响应速度 更小的噪声、更好的温度特性 更小的体积 1 更长的寿命光接收器件基本原理光电效应接收机组件SpeedOptical Metwork Monitoring 光电流Ip=R Pin 量子效率的波长特性hi)光电效应前提hv Ep,A$sfCVo/、ARH(m)=-1+jsRC电压放大器H（M=（U）空钎1+m二1互阻放大器互阻放大器的优点 放大器增益受限于反馈电企、容易实现 放大器带宽宽，无须额外的均需电路从而提高动态范围 较低的噪声指数光接收器件势接收机灵敏度接收机的光口反射的主要指标RECEIVED POWER影响接收机灵敏度的因素-噪声接收器件噪声-量子噪声-APD器件的雪崩噪声前置放大器件的噪声-偏置电阻的热噪声-放大电路的噪声How an APD Can Improve Signobto-noise RatioiMod)6M=1Multiplication gainFig.14 Increasing avalanche multiplication in an APD can improve the signal-to-noise ratio(SNR)of an optical receiver as long as the APD noise is less than the preamplifier rvoise floor SNR.and therefore receiver sensitivity,is optimized at the multiplication Moptimum for which the APD noise becomes comparable to the preamplifier noise.影响接收机灵敏度的因素-带宽高频响应-2.5Gb/s信号,-10Gb/s 信号，低频响应-2.5Gb/s信号,-10Gb/s 信号，要求达到l.8GHz要求达到8GHz要求达到300kHz要求达到100kHz低频响应直接影响允许的长0及长1码个 数接收器件的响应速度（1）封装电容及电阻PIN放大器Cd-分布电容Gd-分布电阻Rs接触电阻Rb偏置电阻接收器件的响应速度（2）transit time 零场区光生载流子的扩散时间 耗尽区光生载流子的漂移时间 雪崩倍增建立时间APD Bandwidth Behavior in Gain RegionsFig.4.APD bandwidth exhibits different behavior in three regions of gain.At low gain,bandwidth is limited by incomplete depletion of the active region.At moderate gain,transit time or RC effects impose a gain-independent bandwidth limit At high gain,a constant gairvbandwidth product allows higher gain only at the cost of proportionally lower bandwidth.Gain-bandwidth for 10-Gbit/se APDsMvltiphcation gainFig.5.Experimental data for 10-Gbit/sec APDs illustrates a gain-bandwidth product of 85 GHz,peak bandwidttis approaching 10 GHz,and high bandwidth at gains as low as M3(see left-hand curve).A larger gain-bandwidth product(95 GHz)can be obtained if low-gain bandwidth is compromised(see right-hand curve).接收器件的响应速度RF接头、2.5Gb/s APD/FET 10Gb/s PIN/FET温度升高，Vb增大，M下降dVb/dT0.1 V/温度升高，噪声电平提高光纤通信系统的光发射机电信号性能检测光通信系统对光发送器件的要求 更长的工作波长 更稳定的波长特征+更灵活的课 更快的响应速度、更小的RIN噪声及线宽(更高的集成度 1 更长的寿命光发送器件基本原理原理自建场P N汩。牛出(0七击区间电荷q PN结99 p-有源区PN结能带结构折射率光强4 ni-n2半导体激光器发光三要素:谐振腔增益物质激励DFB激光器原理_、Basic distributedfeedback design FabroyPerot Las erWavelength Single Frequency(a)Wavelength Multi-mode(b)图2-1DFB激光器的耦合波方程分析激光器的矍态特征+（氏+为）+附（Z,/）=-&%Ct、d 1 d+（go+范）+一小心（Z/）=TKRb（z,t）dz 匕 cton（z J）二组AN（z/）+BN2（z/）+CN3（z/）g（z+R：）ot eV vpoz=O4（oj）=q&（o,。z=L:RB（L,t）=pFfIL,。温度对DFB激165805阈值电流变大 j Z阈值波长!2：向长波长方向移动;二(2:5 O 5 O 5 O 5 O 4433221.1(0)=j.7(0)z=L:rB(L)=pr-rF(Q)e2mLpDFB激光器的直接调制性能张弛振荡不可避免喟啾系数较大:0.7直接调制D FB激光器的例啾定义：=4l-e，加 t/口*/、dE七 Im(E-2)_ a _出1/(21)且 Re(E*变?、.况 dt-017 喟啾因子 正哨啾与色散的影响类似，导致脉冲展宽，缩 短传输距离蜩啾缩短传输距离 随着脉冲在光纤中传输，脉7渝被展宽 无喟啾光源的传输距离：B2*L*D 105(GZ?/5)2*kmps I nm I km)理想无喟啾光源传输距离：、I2.5Gb/s：G.652光纤传输 1000km(17000ps/nm)10Gb/s：G.652光纤传输60km(1000ps/nm)直接调制激光器的传输距离：*2.5Gb/s：G652光纤传输 vl80km(3200ps/nm)外调制技术电吸收外调制器 Mach-Zehnder外调制器-LiNbO3外调制器-III-V外调制器电吸收外调制器Electro-absorption modulatorsPackaged EAMInternal EAM structure物理效应调制器结构Henry系数开态时吸收率消光比Franz-Kledish条型基本上为正大小Stark Shift多量子阱可以达到负小大Wannier-Stark超晶格可以达到负很小小集成电吸收外调制/激光器LaserEA lodulatorBO$C$1n 3t川3Temperatire control thermo-Slavic coo er)集成电吸收外调制/激光器传输性能发送端眼图传输8X80km后眼图LiNbO3外调制器LJUNbOj moduhtor集成lll-v外调制/激光器DWDMQW-DFB激光器温度波长控制/监控电路激光器的要求波长稳定技术-温度反馈控制技术-波长反馈控制技术外调制器2.5Gbit/s光输出信号2.5Gbit/s 驱动器外部波长反馈输入设置输入/监控输出_1_y2.5Gbit/s电输入信号激光器波长的长时间漂移：0.10.2nm采用无源器件进行波长锁定，可以有效防止波 长随着时间的漂移，波长漂移v5GHz波长锁定技术原理一采用Fabrv-Perot标准具sourcedivergent F abry-PerotX o 入 o 40 pmShortLongWavelengthDOXC激光器的要求一波长口传统的DFB激光器的波长调-利用温度调节O.lnm/oC-范围有限可调波长激光器-多段DFB-DBR-VSECL-外腔激光器Table 1.Tunable-laser technical requirements for 2.5-and 10-Gbit/sec optical-networkinq applicationsApplicalionOUMI powerLhe widhlinng rangelinhg limeSia bilily(mW)(MHz)(nm)(msec)(iGHz)Switch ng5-20404010niu lip lexer100 GHz20350 GHz102.525 GHz53215100 GHz20350 GHz10325 GHz103215100 GHz20350 GHz102.525 GHz203215100 GHz52.550 GHz22.525 GHz AccessMicro-ECL大输出光功率，窄线 宽，低RIN,连续调 节，宽调节范围切换时间慢，对振动 敏感长距离、Metro、OADM光发送器件的其它应用 EDFA泵浦激光器980nm/148 Raman放大器Raman amplifierFigure 1,Shown are most of the passive components in a Raman amplifier.While many of the components are similar to those used in an erbium-doped fiber amplifier,the Raman amplifier places additional requirements on the components.光发送器件的安全性要求Table 1.1,550-nm AEL:Average Power at End of Optical FiberSG1SG3aSG3b11.1 dBm18.1 dBm27 dBmINVISIBLE LASER RADIATIONI AV Ji 11 t XP GSJ lit-G Bb AM IICLASS 3B LASER PRODUCI 1Table 2.Limiting Apertures of 1,400-2,600-nm Emissions and Exposure DurationDuration Limiting aperature(d0)10-9 to 0.3 sec 1 mm0.3 to 10 sec 1,510 to 3x104 sec 3.5 mmREFERENCE IEC 825-1 183ms raaxxif coMnnswm um.”CAUTIOI USE OF CONTROLS OR ADXISTMENTS OR PERFORMANCE OF PROCEDURES OTHER THAN SPECIF。心口 N MAY RESULT IN HAZARDOUSRADIATION DCPOSURE CAUTIONSTATIC SENSITIVE dcviceOfiSERVE PRECAUTIONS谢谢