通过求解耦合非线性薛定谔方程, 数值分析了8×40Gbit/s波分复用(WDM)系统中色散、偏振模色散(PMD)、非线性效应和信道间距对载波抑制归零-差分正交相移键控(CSRZ-DQPSK)调制格式的影响。结果表明不同信道间传输特性相似, 而在高速、窄信道间距的WDM系统中偏振模色散(PMD)和非线性效应的影响会进一步加剧。当入纤功率从8dBm增大到11dBm时, CSRZ-DQPSK调制格式Q值从7.8dB线性降低到2.8dB, 而当信道间距低于100GHz后系统性能急速变差。

By solving coupled nonlinear Schrdinger equation, the impacts of dispersion, polarization mode dispersion (PMD), nonlinear effect and channel spacing on carrier-suppressed return to zero-differential quadrature phase shift keying (CSRZ-DQPSK) modulation format were numerically analyzed in 8×40Gbit/s wavelength division multiplexing (WDM) systems. Results show that transmission characteristics of different channels are similar, and the influence of PMD and nonlinear effect can be further intensified in high-speed and narrow channel spacing WDM systems. The Q value of CSRZ-DQPSK modulation formats reduces linearly from 7.8dB to 2.8dB when the input power increases from 8dBm to 11dBm, and when the channel spacing is less than 100GHz, the system performance rapidly becomes poor.