局部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,研究了激光脉冲在局部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、传输距离一定时,当f=-1禁带之上能带底时,调制不稳定性增益的强度最强、宽度最窄;当远离能带底时强度减弱、宽度变宽;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,增益谱都受到局部高斯变迹函数的制约。

Modulation instability of fiber Bragg gratings with the part Gaussian apodization

The coherently coupled nonlinear Schrdinger(NLS) equation of the propagation of a light pulse in fiber Bragg gratings is utilized.Modulation instability of laser pluses is studied in fiber Bragg gratings with the part Gaussian apodization function not only in anomalous dispersion regime but also in normal dispersion regime.The results show that modulation instability can be produced both in anomalous dispersion regime and in normal dispersion regime.The regular gain spectra are produced obviously when input power reaches definite value and the gain spectrum's intensity is strengthened and width is narrowed with increase in parameter f in anomalous dispersion regime.The modulation instability can be produced from fixed value to infinite when the input power is in the field of modulation instability in normal dispersion regime.Furthermore,the gain spectra are restrained by the part Gaussian apodization function not only in anomalous dispersion regime but also in normal dispersion regime.