用统一耦合模理论分析光纤光栅耦合器型滤波器的滤波特性

Analysis of Fiber Grating Filters Written in Fiber Coupler by Employing the Unified Coupled-Mode Theory

通过在光纤倏逝场间的耦合作用中引入光栅折射率调制扰动,推导出用于分析各种光纤光栅耦合器型滤波器响应特性的统一耦合模方程,并给方程中涉及的参数赋予了明确的物理意义。在此基础上,采用Broyden迭代结合打靶法数值分析了三种光纤光栅耦合器型滤波器的滤波响应特性。分析了相关参数对下话路滤波响应的影响,通过优化参数,可以使光栅辅助耦合器、光栅反射耦合器和光栅破坏耦合器分别达到95%,85%和99%的下话路效率。并实验制作了反射峰值分别达到15和18 dB的光栅辅助耦合和光栅反射耦合器。

By introducing the grating refractive modulation into the evanescent field coupling,the unified coupledmode equation for all kinds of fiber grating filters written in fiber coupler is obtained,which parameters have specific physical meaning.The filtering response of three kinds of fiber grating filters written in fiber coupler are analyed by numerical methed of Broyden and shooting.The influences of relative parameters on the filtering response characteristics are investigated theoretically.Drop channel efficiency of 95%,85%and 99%can be obtained for grating assisted coupler,grating reflection coupler and grating frustrate coupler by optimizing parameters.Grating assisted coupler and grating reflection coupler are fabricated with reflectivity 15 and 18 dB.