A summary of the correlational concepts of PMD and its statistics nature is given in chapter 4. First-order PMD dynamic compensation and its simulation are achieved by use of Q factor as feedback control signals, and the control arithmetic is also shown. 第四章对偏振模色散的有关概念及其特性等进行总结,利用Q因子作为反馈控制信号进行一阶PMD动态补偿及仿真,并给出控制算法。