为提高模拟超连续谱(SC)产生的精度, 在不增加计算量的情况下对传统分步傅里叶算法作了一定的改进。传统分步傅里叶算法只考虑初始脉冲中心频率对应的色散系数, 而超连续谱的光谱范围很大, 当色散系数随波长变化较大时, 传统算法会存在较大误差。改进的算法将整个脉冲包络看成由多个单一频率分量组成, 对各频率分量分别处理, 从而将整个脉冲包络内所有频率分量的色散系数都考虑在内。将改进算法分别用于模拟色散曲线只包含一个和两个零色散点的光子晶体光纤(PCF)中超连续谱的产生, 并与传统算法的模拟结果相比较, 结果表明,改进算法在模拟单零色散光子晶体光纤中超连续谱产生时优势不明显, 但对模拟双零色散光子晶体光纤中超连续谱产生却有一定优势。

In order to improve the precision of simulated supercontinuum (SC) generation, the split-step Fourier algorithm is modified without increasing the computation amount. Traditional algorithm only refers to the dispersion coefficient of the central frequency. Due to the wide range of the supercontinuum, the error of the result would be big by using the traditional algorithm if the slope of the dispersion coefficient is large. According to the modified algorithm, the pulse could be regarded as the combination of many elements each with only one frequency. The elements with different frequencies could be processed seperately by using the modified algorithm, so the dispersion coefficients of all the frequencies could be refered to. The modified algorithm is applied in simulating the supercontinuum generation in the photonic crystal fibers with one and two zero dispersion wavelengths. And the results are compared with those of traditional algorithm. The simulation results show that the superiority of the modified split-step Fourier algorithm is not obvious in the photonic crystal fibers (PCF) with only one zero dispersion wavelength, but having certain superiorities in simulating the supercontinuum generation of the photonic crystal fibers with two zero dispersion wavelengths.