光电子技术, 2011, 31 (1): 46, 网络出版: 2011-04-28
一种降低相干光OFDM系统非线性效应的方法
A Method for Fiber Nonlinearity Mitigation for Coherent Optical OFDM System
相干光通信 正交频分复用 光纤非线性 前向补偿 coherent optical communications orthogonal frequency division multiplexing fiber nonlinearity pre-compensation
摘要
相干光正交频分复用(Coherent optical-orthogonal frequency division multiplexing,简称CO-OFDM)可有效降低光纤色散和偏振模色散对系统的影响,是近年来光传输领域研究热点之一。但由于OFDM高的峰均值功率比(PAPR)和较窄的载波间隔(几十兆赫兹),CO-OFDM系统对光纤非线性十分敏感,严重影响系统传输性能。分析了CO-OFDM系统中光纤非线性作用,介绍了一种新的非线性补偿方法,实现简单,计算复杂度低,可有效补偿系统传输中的非线性影响。仿真结果表明,在8 000 km长距离传输系统中,补偿后的CO-OFDM系统,非线性门限提高5 dBm;色散系数会影响非线性补偿效果,色散系数为16 ps/(nm·km)时,系统品质因子Q提高0.6 dB,色散系数为6 ps/(nm·km)时,Q值提高2 dB以上。
Abstract
Coherent optical orthogonal frequency-division multiplexing (CO-OFDM) is being considered as a promising technology which has been demonstrated to combat fiber chromatic dispersion and polarization-mode dispersion (PMD). However, owing to high peak-to-average power ratio (PAPR) and closely-packed subcarriers (tens of MHz), CO-OFDM system is quite sensitive to nonlinearity. The fiber nonlinearity for CO-OFDM system and a simple but computationally efficient nonlinearity compensation technique are introduced to improve the fiber nonlinearity tolerance and without requiring additional optical components. With such a scheme, simulation shows that the nonlinear threshold is increased by 5 dBm by the nonlinearity compensation method. A 0.6 dB increase in system Q value is possible for 16 ps/(nm·km) fibers in an 8 000 km system, and the Q value increases to 2 dB for 6 ps/(nm·km) fibers.
郝耀鸿, 李玉权, 王荣. 一种降低相干光OFDM系统非线性效应的方法[J]. 光电子技术, 2011, 31(1): 46. Hao Yaohong, Li Yuquan, Wang Rong. A Method for Fiber Nonlinearity Mitigation for Coherent Optical OFDM System[J]. Optoelectronic Technology, 2011, 31(1): 46.