偏振模色散补偿中偏振度与差分群延时关系的理论分析和实验

偏振模色散是高速光纤通信系统的主要问题之一。在用偏振度作为反馈信号的动态偏振模色散补偿系统中，偏振度与差分群延时的关系对于准确快速的动态偏振模色散补偿很重要。推导出了准单色光波情况下任意波形和高斯脉冲的偏振度的数学表达式，理论分析了高斯脉冲情况下分光比、脉冲宽度和连续脉冲个数分别对偏振度与差分群延时关系的影响，并用10Gbit／s归零／不归零伪随机码序列进行了实验，实验证明了理论推导和理论分析的正确性。实验还表明偏振度的大小与脉冲啁啾和光纤色散无关，从而肯定了将实际光脉冲化简为准单色光波分析的可行性。

Theoretical Analysis and Experiment of Degree of Polarization-Differential Group Delay for Polarization Mode Dispersion Compensation

Polarization mode dispersion (PMD) causes severe signal impairments in high bit-rate optical transmission systems. It is important to know how does the degree of polarization (DOP) change with differential group delay (DGD) when DOP is feedback information for adaptive PMD compensation. The mathematical expression between DOP and DGD is derived for arbitrary waveshape and Gaussian pulse. Then the relationship of DOP-DGD with different power splitting ratio, width of pulse, and amount of pluses is theoretically analyzed. Experiments with 10 Gbit/s return-to-zero/non-return-to-zero (RZ/NRZ) pseudo random sequence are conducted and comparison between theoretical calculation and experimental results is made. The comparison showed that they matched closely. It is also verified that DOP was independent of chirp and fiber dispersion in experiment, which made the theoretical analysis of DOP-DGD easy.