反馈时延对高速率光数字接收机时域均衡器影响的分析  

Effect of the feedback time delay on the time-domain equalizer for high-speed optical digital receivers

作　　者：许渤[1] 郭群[1] 谭敏[1] 邱昆[1] 

机构地区：[1]电子科技大学通信与信息工程学院,光纤传感与通信教育部重点实验室,四川成都611731

出　　处：《光电子．激光》2015年第11期2096-2103,共8页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金(61471088)资助项目

摘　　要：时域均衡器(TDE)是高速率相干光数字接收机的重要功能模块之一。从TDE的设计需要出发,本文详细研究了误差信号的反馈时延对其收敛性能的影响,提出了一种简化的理论分析方法,并通过对光纤色散信道的仿真验证了方法的有效性。分析表明,当TDE使用较小的迭代步长时,反馈时延对TDE收敛的影响很小,且TDE在收敛后的性能与无反馈时延的理想情况相同;但是,反馈时延的增加,会造成TDE抽头系数的振荡,从而导致TDE的发散;同时,反馈时延会大幅降低允许使用的最大迭代步长,造成TDE收敛速度的降低。本文采用数值仿真的方法对光纤色散信道的TDE进行了分析,其结果验证了上述理论分析方法的有效性,并获得了不同的反馈时延下所允许使用的最大迭代步长,其值将随着反馈时延的增大由1.0减小至0.1。Time-domain equalizer（TDE）is one of the most important modules in high-speed coherent optical digital receivers.Starting from the implementation need,this paper analyzes and studies the effect of the feedback delay on the convergence of the time-domain equalizers in details,proposes a simplified theoretical analysis method,and verifies its effectiveness through simulation results with optical fiber dispersive channels.The theoretical analysis results show that for small iteration step size,the feedback delay has negligible effect on the equalizer′s convergence,and the equalizer′s performance after convergence has no difference with respect to the ideal case of no feedback delay.However,as the feedback delay increases,the feedback delay causes the equalizer′s coefficients to oscillate and the equalizer becomes divergent as a result of large feedback delays.Meanwhile,the feedback delay will greatly reduce the maximum allowed step size for the equalizers and slow down the convergence speed.Then,we study the time-domain equalizers with optical fiber dispersive channels based on numerical simulations.The simulation results verify the effectiveness of the above theoretical method.Based on simulations,the maximum allowed step sizes at different feedback delays are also obtained,which decrease from 1to 0.1as the feedback delay increases.

关 键 词：相干光通信 相干光接收机 信道均衡 时域均衡器(TDE) 

分 类 号：TN929.11[电子电信—通信与信息系统]