全固态带隙结构光子晶体光纤中非线性过程的数值模拟

Numerical simulation for nonlinear evolution in all-solid photonic bandgap fibers

全固态带隙结构光子晶体光纤能够同时提供大模场面积和可控色散特性,为高功率下的非线性传输过程提供了一种新的介质,尤其在构成全光纤色散补偿和高功率孤子传输器件方面具有重要的应用价值。利用改进的广义非线性薛定谔方程数值模拟了全固态带隙结构光子晶体光纤中的非线性过程,分析了这种光纤中由于带隙特性和色散特性的共同作用,对飞秒激光非线性传输过程的影响,其中最明显的效应就是带隙特性对孤子白频移有很强的抑制作用。进一步详细讨论了入射脉冲峰值功率、带隙宽度以及带隙中心位置对非线性传输过程的影响。

All-solid photonic crystal fiber has the unique property which can used to shift the zero-dispersion wavelength down to visible light, while maintain a large mode area which is one order of magnitude larger than that may be achieved in index guiding fiber. It can be a very valuable nonlinear material in dispersion compensation and high power soliton propagation, especially for the all-fiber devices. Numerical calculation is carried out for the simulation of nonlinear evolution in all-solid photonic crystal fiber with a modified general nonlinear Schr5dinger equation. The bandgap has strong effects on the suppression of soliton selffrequency shift during the nonlinear process. The effects of peak power of femtosecond laser, the bandwidth and central wavelength of the bandgap on the nonlinear process are also analyzed.