少模光纤通信系统中的自适应频域均衡算法  

Adaptive frequency-domain equalization for few-mode fiber transmission systems

作　　者：黄战华[1] 王云立[1] 李桂芳[1] 张珊[1] 

机构地区：[1]天津大学精密仪器与光电子工程学院光电信息技术教育部重点实验室,天津300072

出　　处：《激光技术》2017年第1期124-128,共5页Laser Technology

基　　金：国家九七三重点基础研究发展计划资助项目(2014CB340100)

摘　　要：少模光纤模式复用存在模式耦合和差分模式时延,必须通过自适应均衡算法补偿。为了降低长距离少模光纤通信系统中自适应均衡算法的复杂度,采用基于变步长-频域块最小均方算法的多输入多输出均衡器对2×2模分复用系统解复用。利用频域块最小均方自适应算法修正均衡器权系数,并通过变步长函数调整步长因子,兼顾算法收敛速度和收敛性能。算法可通过快速傅里叶变换降低计算复杂度。在112Gbit/s的1000km少模光纤高速通信仿真系统中,保证相同收敛速度情况下,提高信号Q2因子3.7d B,并在可编程现场门阵列上验证了100km少模光纤通信系统时的算法性能。结果表明,该算法能够实现模分复用系统的信号解复用,达到快速收敛、低稳态失调的目的。Modal crosstalk and differential mode delay in mode-division multiplexing in few-mode fiber must be compensated for with adaptive equalization algorithm. For the purpose of decreasing complexity of adaptive equalization algorithm in long-haul few-mode fiber communication system, a multiple-input multiple-output equalizer with variable step-size frequency-domain-block least mean square（VS-FBLMS） algorithm was proposed to uncouple a 2×2 mode-division multiplexing system. Compromising the conflicting requirements of convergence speed and convergence performance, FBLMS adaptive algorithm was employed to update equalizer taps and modify step-size factor with variable step-size function. Furthermore, the algorithm decreased the computational complexity by using fast Fourier transform. In a 112Gbit/s high-speed communication simulation system over 1000km in few-mode fiber, signal Q2 factor increased 3. 7dB with same convergence speed. The performance of the algorithm was tested on field programmable gate array with a 100km few mode fiber communication system. The study demonstrates that the algorithm successfully uncouples the signals of mode-division multiplexing system and realizes fast convergence and low disorder.

关 键 词：光通信 变步长-频域块最小均方算法 频域均衡 少模光纤 模式复用 

分 类 号：TN929.11[电子电信—通信与信息系统]