建立了多跨距RZ-DPSK(归零差分相移键控)色散管理波分复用的简并四波混频噪声标准差的理论计算模型, 该模型考虑到了比特序列的随机性和脉冲初始相位的随机性两种随机因素的影响。利用该模型进行了实例分析, 研究结果表明: 平均功率相同的情况下, DPSK调制信号的噪声标准差值比OOK(开关键控)调制信号的小; 比特率的变化对调制信号的噪声标准差值的影响不大; 平均功率对调制信号的噪声标准差有很大的影响, 随着平均功率的增大, 噪声标准差的值呈近似指数形式的增大。

This paper presents a theoretical model for evaluating the standard deviation of Four-Wave-Mixing (FWM) noise in multi-span dispersion managed WDM systems with Differential Phase-Shift-Keying (DPSK) modulation. This model takes into consideration the effects of the randomness of bit sequence and initial phase of the pulses in each channel. Using this model, it analyzes some practical cases. The results show that with the same average power, the noise deviation ratio of DPSK modulated signals is smaller than that of On-Off Keying (OOK) modulated signals, that the variations of bit rates have little effect on the noise deviation value of the DPSK modulated signals, while the average power has great influence. With the increase of the latter, the voice deviation value increases almost exponentially.