利用数值方法求解了广义非线性薛定谔方程，分析了中红外超连续谱在两级光纤中的产生机制。模拟结果表明，自相位调制、受激拉曼散射和色散波放大使频谱在带两个零色散波长的高非线性SF57光子晶体光纤（PCF）中得到了极大的展宽。在较短的SF57-PCF中，获得了3 dB功率谱覆盖范围为1800~3500 nm的高带宽、平坦度好的中红外超连续谱。而且，超连续谱的长波长边沿随着抽运脉冲峰值功率的增大而进一步展宽。

By numerically solving the generalized nonlinear Schrdinger equation, mid-infrared supercontinuum generation in two cascaded fibers has been analyzed. The simulation results show that the spectrum has been greatly broadened in the high nonlinear SF57 photonic crystal fiber(PCF) with two zero dispersion wavelenghs by self-phase modulation, stimulated Raman scattering and dispersive waves amplification. Spectrally smooth, highly broadband mid-infrared supercontinuum in a short piece of SF57-PCF is presented here. The spectral range extends from 1800 to 3500 nm with the 3 dB spectral power density. It is found that the long wavelength edge of supercontinuum is further broadened with the increase of the peak pump power.