相干光OFDM系统中的偏振相关损耗效应  

Polarization Dependent Loss in Coherent Optical Systems

作　　者：郝耀鸿 冷丹 方涛[2] 

机构地区：[1]解放军特种作战学院,广州510502 [2]解放军理工大学通信工程学院,南京210007

出　　处：《应用科学学报》2014年第1期39-43,共5页Journal of Applied Sciences

基　　金：国家"973"重点基础研究发展计划基金(No.2012CB315600);江苏省自然科学基金(No.Bk2012508)资助

摘　　要：相干光正交频分复用系统(coherent optical OFDM system,CO-OFDM)是目前高速光传输领域的研究热点,但系统受偏振模色散(polarization mode dispersion,PMD)和偏振相关损耗(polarization dependent loss,PDL)影响严重.为此,通过数学分析和数值仿真,研究了CO-OFDM系统中PDL与一阶PMD相互作用的数学模型,对信号均衡等关键实现进行讨论,并加以验证.结果表明:偏振效应对光OFDM信号幅度及相位产生噪声干扰,通过发送导频序列可有效实现信号均衡,当传输距离为720km,相对损耗因子α=0.5时,较不考虑PDL影响(α=1)系统的Q值约降低0.8dB.由于输出偏振态随频率产生旋转,PMD效应在一定程度上可缓解PDL所致系统损伤.Coherent optical OFDM system （CO-OFDM） is a promising technology in high speed long-haul optical transmission. Polarization dependent loss （PDL） and first-order polarization mode dispersion （PMD） influence system performance seriously in high speed transmission. The mathematical model of transmission is analyzed, and a signal equalization scheme is proposed for CO-OFDM systems. Numerical simulation is done to validate the method and the estimation algorithm. Analysis and simulation results show that the polariza tion effect may cause amplitude noise and phase noise, which can be eliminated with signal equalization. At a length of 720 km, the Q value is improved by 0.8 dB for a = 1 compared with a = 0.5. Meanwhile, the first-order PMD may reduce the PDL effect by rotation of SOP （state of polarization）.

关 键 词：相干光通信 正交频分复用 偏振相关损耗 偏振模色散 

分 类 号：TN929.5[电子电信—通信与信息系统]