基于OptiSystem软件平台提出了一种关于FWM（四波混频）噪声对系统性能影响程度进行评估的非线性分离模型，同时提出了一种新型的色散图。利用该模型对同偏振态33信道DWDM（密集波分复用）系统的FWM噪声进行了仿真。仿真结果表明，在给定的系统条件下，所有信道都采用DPSK（差分相移键控）调制的纯DPSK系统比采用DPSKOOK（开关键控）混合调制的系统有更好的非线性容限。对于新型色散管理系统，当单信道速率和入射光功率较大时，DPSKOOK的混合调制系统与纯DPSK调制系统相比，FWM噪声对系统性能影响更大。

On the basis of the OptiSystem platform, we present a nonlinear separation model for evaluating the impacts of FourWaveMixing (FWM) noise on the system performance and also a novel dispersion map. By using this model, we simulate the FWM noise of the copolarization Dense Wavelength Division Multiplexing (DWDM) systems with 33 channels. The simulation results show that under the given system conditions, a pure Differential PhaseShift Keying (DPSK) (i.e. all channels are DPSK modulated) system has better nonlinear tolerance than a hybrid DPSK and OnOff Keying (OOK) system. For novel dispersion management systems, with the increase of bit rate and incident optical power per channel, the impacts of FWM noise on the performance of the hybrid DPSK and OOK DWDM system are greater than those on the pure DPSK system.