建立了强度调制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，此理论模型考虑到了两种随机因素的影响：各信道内的比特流的随机性及脉冲初始相位的随机性。信道间的脉冲走离效应使色散管理光纤链路中的脉冲碰撞位置的分布比较复杂，这些碰撞位置又会对四波混频噪声标准差的值产生较大影响，所建立的理论模型充分考虑到了这种碰撞位置的影响。利用这个理论模型进行了相关计算，计算结果表明，优化的色散管理方案在保证脉冲稳定传输的同时，能获得较小的四波混频噪声标准差；当系统选择较小的占空比时，优化各信道脉冲的相对初始时延能较大程度地减小四波混频效应的不利影响。

A generalized model to evaluate variance of four-wave-mixing (FWM) noise in dispersion managed wavelength-division-multiplexing (WDM) system with intensity modulation scheme is presented. The information sequence of bits and initial phase of bit sequences are random. The model gives the statistical results of them. Simultaneously, the positions of inter-channel pulse collisions are also included in the model, which are more difficult to be located in dispersion managed fiber link than in constant dispersion fiber link due to inter-channel pulse walk-off. Some examples show that optimized dispersion management schemes are important to decrease FWM noise, and meanwhile make pulses transmit steadily. It is also shown that when the pulse duty cycle is small, initial relative time delay of bit sequence plays an important role in obtaining minimized value of FWM noise variance.