升余弦变迹布拉格光纤光栅中的调制不稳定性

利用相干耦合非线性薛定谔方程,研究了激光脉冲在升余弦变迹布拉格光纤光栅中传输时,在反常色散区和正常色散区所产生的调制不稳定性。结果表明在反常色散区和正常色散区都能产生调制不稳定性;在反常色散区,当输入功率达到一定数值时,产生明显的规律性增益谱;在正常色散区,在产生调制不稳定性功率区域,调制不稳定性存在并从给定值一直持续到无穷;在反常色散区和正常色散区,增益谱都受到升余弦变迹函数的制约。

Modulation Instability of Fiber Bragg Gratings with Raised Cosine Apodization

The coherently coupled nonlinear Schrodinger equation is used to study the modulation instability of laser pulses propagating in fiber Bragg gratings with raised cosine apodization function in both anomalous and normal dispersion regimes. The results show that modulation instability is produced in both anomalous and normal dispersion regimes. The obvious regular gain spectra have been produced when the input power reaches a certain value in anomalous dispersion regime. The modulation instability in normal dispersion regime rises from a fixed value to infinite when the input power is in the range that can produce modulation instability. Furthermore, the gain spectra have been restrained by raised cosine apodization function in both dispersion regimes.