【摘要】 基于长周期光纤光栅的模式耦合机理,提出一种快速模拟长周期光纤光栅折射率特性的方法。该方法在计算包层模式的有效折射率时分开计算,在环境折射率小于包层折射率时采用二分法和分步搜索法结合计算包层模式的有效折射率,在环境折射率大于包层折射率时采用Nelder-Mead加分步搜索法求解包层模式的有效折射率。在应用谐振波长的决定式求解与环境折射率的匹配的谐振波长时,采用变区间应用二分法求解而不是传统的逐步搜索法求解谐振波长。数值结果与实验结果做了对比,两者基本一致。实践证明,该方法方便快捷,比一般的方法速度提高7倍以上。更多还原

【Abstract】 Based on the coupled-mode theory,a new method of simulating LPFG refractive index characteristics rapidly is introduced.With this method,the effective refractive index of cladding modes is calculated separately.Dichotomy is adopted when the circumstance refractive index is less than the cladding index,while Nelder-Mead is applied to obtain the effective refractive index of cladding modes when the circumstance refractive index is greater than the cladding index.When solving resonant wavelength with the phase-matching formula,the method changes the search range and uses the dichotomy instead of the traditional step by step search method to obtain the resonant wavelength.The results are also the same with comparison to the experimental outcome.This method is proved to be swifter,somewhat seven times faster than the ordinary ways.更多还原