Through computing the eye openings of DQPSK formats under different PMD conditions, it is found that NRZ DQPSK, as compared with RZ DQPSK, incurs smaller eye opening due to PMD.

• 计算了不同偏振模色散影响下的各种调制格式的眼开度，发现在一阶偏振模色散情况下，非归零差分正交相移键控格式与归零差分正交相移键控格式相比受偏振模色散影响眼开度要小；