Abstract:The impact of XPM on the microwave photonic switching with NOLM is analyzed by the split-step Fourier method (SSFM) that can solve the coupled nonlinear Schr(o)dinger equation (CNLSE). The simulation results show that XPM induces the distortion of waveforms and the leak of side lobes. And the larger the modulation bandwidth is, the larger the leak of side lobes is. Furthermore, the power transmission function of NOLM Tm is distorted because of the XPM-induced nonreciprocity: Tm decreases when the splitting ratio of the couplerf ∈ (0,0.5) and increases when f ∈ (0.5,1.0).