高斯变迹布拉格光纤光栅中的调制不稳定性

利用激光脉冲在光纤光栅中传播时所遵守的相干耦合非线性薛定谔方程,研究了激光脉冲在高斯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，产生明显的有规律的增益谱；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；并且，在反常色散区和在正常色散区，增益谱都受到高斯变迹函数的制约. 关键词： 高斯变迹 布拉格光栅 调制不稳定性 增益

Modulation instability of fiber Bragg gratings with Gaussian apodization

The coherently coupled nonlinear Schrdinger (NLS) equation of the propagation of light pulse in fiber Bragg gratings has been utilized to study the modulation instability of laser pluses in fiber Bragg gratings with Gaussian apodization function, not only in the anomalous dispersion regime, but also in the normal dispersion regime. The results show that modulation instability can occur in both regimes. The regular gain spectra are observed obviously when input power reaches a definite value in the anomalous dispersion regime. The modulation instability can increase from a fixed value to infinity when the input power is in the region of modulation instability in normal dispersion regime. Furthermore, the gain spectra are restrained by Gaussian apodization function in both regimes.