相干光OFDM系统中直接判决均衡器的性能研究  

Performance Analysis on the Decision-directed Equalizer in Coherent Optical OFDM

作　　者：袁建国[1] 梁天宇[1] 何清萍[1] 何丽[1] 王永[1] 

机构地区：[1]重庆邮电大学光纤通信技术重点实验室,重庆400065

出　　处：《半导体光电》2012年第2期245-248,共4页Semiconductor Optoelectronics

基　　金：国家自然科学基金项目(61071117;61003256);重庆市自然科学基金项目(2010BB2409);重庆市教委项目(KJ110519)

摘　　要：理论上分析了相干光正交频分复用(CO-OFDM)系统中相位噪声(PN)和色度色散(CD)对星座图的影响,并详细探讨了CO-OFDM系统中基于导频的直接判决均衡器(DDE)的原理,还对其性能进行了仿真分析。仿真结果表明:在不同的传输距离下,DDE的误码率都能呈瀑布状下降至10-3这一公认的前向纠错(FEC)门限,使得后续的FEC模块可以让误码率迅速降低。此外,在激光器线宽小于100kHz时,DDE的误码性能并没有大幅度的提升。因此,在选择DDE作为均衡器的CO-OFDM系统中,应折中考虑激光器线宽和误码性能的关系,基于成本考虑建议采用100kHz激光器。The theory model of phase noise（PN） and Chromatic Dispersion（CD） in Coherent Optical Orthogonal Frequency-Division Multiplexing（CO-OFDM） systems is theoretically analyzed and the effect of PN and CD on the constellation is also given.Based on the analysis,the principles and design of pilot-based decision-directed equalizer of CO-OFDM systems are probed in detail.Then numerical simulations on the performance of Decision-directed Equalizer（DDE） were implemented.The simulation results show that the bit error ratio（BER） performance of the DDE can always achieve 10-3 which is the commonly-reported Forward Error Correction（FEC） threshold,and this can make the following FEC module reduce the BER rapidly.Furthermore,the performance of DDE is not improved obviously when the laser linewidth is smaller than 100 kHz.Therefore,the laser with 100 kHz linewidth is recommended in CO-OFDM systems with DDE for the consideration on tradeoff between cost and BER performance.

关 键 词：相干光正交频分复用 相位噪声 色度色散 直接判决均衡器 

分 类 号：TN929.11[电子电信—通信与信息系统]