光子晶体光纤中调制不稳定现象与超连续光谱的产生

Modulation Instability and Supercontinuum Generation in Photonic Crystal Fiber

研究了光子晶体光纤中调制不稳定性效应.从非线性薛定谔方程出发,计算和分析了光子晶体光纤中反常色散区以及正常色散区内的调制不稳定性现象,详细讨论了超短脉冲的脉宽、峰值功率、高阶色散和高阶非线性效应(如脉冲内喇曼散射、自陡峭效应)对调制不稳定性产生的影响.结果表明:二阶色散对调制不稳定性的影响要远大于三阶色散,同时也发现随着初始脉冲宽度的减小,调制不稳定性旁瓣增大但是强度有所降低.另外还发现高阶非线效应如自陡峭和喇曼效应会在不同程度上抑制调制不稳定性.

The investigation of modulation instability （MI） in the Photonic crystal fiber （PCF） was reported. Using the nonlinear generalized Schrodinger equation,the MI in the anomalous as well as in the normal dispersion region were calculated and analysed. The impacts of the input pulse duration, the pulse peak power, the high-order dispersion and the high-order nonlinear effects （such as the intrapulse stimulated Raman scattering and self-steepening effects）on the MI were also expatiated. The numerical results show that the impact of the second-order dispersion on the MI is more influential than that of the third-order dispersion. It was found that the MI sidebands expand while its spectral intensity decreased as the input pulse duration was reduced. It was also found that the intrapulse stimulated Raman scattering and self-steepening effects can restrain the MI in different extents.