长周期光纤光栅包层参数对透射谱影响的数值分析

Numerical Analysis of Long Period Fiber Grating Cladding Parameter s Effect on Spectrum

以耦合模理论为基础,采用三层阶跃折射率光纤模型,导出了长周期光纤光栅透射率、峰值带宽的解析表达式,针对包层折射率和半径变化对透射谱的影响加以数值模拟.结果表明谐振波长位移与折射率的变化基本呈线性关系当包层半径较小时谐振波长位移及透射率的变化均较为明显,反之,其相应的变化则渐趋平缓.

Based on coupled-mode theory and a simplified three-layered fiber model,the formulas about transmission rate and peak value bandwidth of long period fiber grating are deduced. Computer is used to simulate the relation of resonance wavelength with cladding refractive index and radius. The results show that resonance wavelength shift in proportion to refractive index on the whole,and both of its variety and the change of transmission rate are marked when cladding radius is less. Contrarily,it is not the case ...