高阶色散和高阶非线性对交叉相位调制不稳定的影响

Effects of high-order dispersion and high-order nonlinearity on cross-phase modulational instability

以包含高阶色散和高阶非线性的广义非线性薛定谔方程为基础,研究了有损光纤中交叉相位调制(XPM)不稳定增益谱,分析了四阶色散、五阶非线性系数以及光纤损耗系数对增益谱的影响。结果表明:在光纤的正、反常色散区,四阶色散导致XPM不稳定均发生在两个频谱区。正五阶非线性使增益谱的谱宽和峰值增大,负阶非线性使增益谱的谱宽和峰值减少。光纤损耗对增益谱的谱宽有较大影响,它使增益的谱宽变窄,且随传输距离的增大谱宽变得更窄。

Based on the extended nonlinear Schrtidinger equation, the gain spectrum of cross-phase modulation （XPM） instability in fiber was investigated with high-order dispersion and high-order nonlinearity considered. The effects of fourth-order dispersion, quintic nonlinearity and fiber loss on the gain spectra were analyzed. The results showed that because of fourth-order dispersion, XPM instability oceured at two spectrum regions in both the normal and the anomalous dispersion regimes of fiber. The positive quintic nonlinearity would make the width and the peak value of the gain spectra larger. The negative quintic nonlinearity would make the width and peak value of the gain spectra smaller. Results also showed that fiber loss reduced the frequency range of the gain spectrum, and the frequency range became smaller with the propagation distance increasing.