针对偏振模色散(PMD)限制光纤通信系统向高速率和长距离发展的问题,本文提出了基于偏振度(DOP)监测的PMD 动态自适应补偿系统的设计方案。该方法根据DOP 与差分群时延(DGD)之间的关系,通过控制算法实现DOP 最佳值的搜索和跟踪,由DOP 的变化反映PMD 的大小及其补偿效果,采用调节偏振控制器波片的角度和可变时延线,调整两基本偏振态,不断优化DOP 使其趋于最佳值,构建了闭环补偿系统。实验结构表明,发生裂化的信号波形得到了有效恢复,眼图张开度得到明显改善。实验中,系统的补偿响应时间约为110 ms,补偿后信号的误码率为3.59e-16,达到了系统对传输误码率的要求。

To avoid the limitation of Polarization Mode Dispersion (PMD) to the long-distance and high-rate optical fiber communication system,a dynamic adaptive PMD compensation system based on Degree of Polarization (DOP) was designed. According to the relationship between DOP and Differential Group Delay (DGD),the optimum value was searched and tracked by the control algorithm,and the value of PMD and its compensation effect could be reflected by DOP. Through adjusting the angle of waveplates in the polarization controller and the length of the variable delay line,the two principal states of polarization were adjusted to optimize DOP,and a close-loop compensation system was established. It was demonstrated from the experimental results that the worsening signal waveform was resumed effectively,and the opening of the eye diagram was improved obviously. The response time of the compensation system was about 110ms,and the Bit Error Rate (BER) was 3.59e-16,which satisfied the requirement for BER in the transmission system.