光纤布拉格光栅非线性传输特性的数值仿真

摘要

One-step system based on the semi-implicit Runge-Kutta method and simple iteration is designed for simplifying computation and avoiding the distortion of simulation results caused by shock response in solving a set of nonlinear coupled equations of fiber Bragg grating (FBG). The feasibility of the design is verified by comparing with other calculation methods and experimental results. The computational workload is greatly reduced when the same accuracy is required in simulating. Unified numerical simulation model based on physical process of optical wave transmission in grating is established under static and dynamic circumstances. Smoothing skills in simulation are researched. Nonlinear transmission characteristics of FBGs are studied numerically when continuous wave (CW) and pulse were input. The results show that the switching threshold power of phase-shift grating is lower than of uniform grating and ail-optically tuned delay can be achieved by nonlinear effect in fiber Bragg grating.%为简化数值求解光纤布拉格光栅的非线性耦合模方程组,避免冲击响应带来数值仿真结果失真,设计了基于半隐式龙格-库塔法及简单迭代的单步系统.与其他方法和实验结果进行对比,验证了该方法的可行性.在相同精度要求下,该方法能够极大地减小计算工作量,实现简单且能够避免数值计算发散.利用该方法建立了光纤布拉格光栅静态和动态情况下统一的数值仿真模型,并设计了仿真中所采用的平滑技术.数值研究了连续波和脉冲输入情况下光纤布拉格光栅的非线性传输特性,静态结果显示相移光栅的开关阈值功率比均匀光栅的低.在动态情况下,对比不同峰值功率脉冲的输出时域特征显示,通过光纤光栅可实现非线性全光调谐延迟.