应用耦合模理论, 给出均匀布拉格光纤光栅在考虑光栅致双折射时的透射与反射系数的解析式, 按照测量偏振相关损耗(PDL)的确定性与非确定性两种方法, 推导出了均匀布拉格光纤光栅中偏振相关损耗的解析公式。理论分析表明, 该公式能够准确分析弱双折射光纤或者各向同性光纤上写入的均匀布拉格光纤光栅的偏振相关损耗特性, 同时数值模拟高双折射光纤上写入的均匀布拉格光纤光栅偏振相关损耗特性, 得到的结果也与已有实验曲线相近。

Employing coupling mode theory, the reflection and transmission coefficients of uniform fiber Bragg gratings with the grating induced birefringence were given. Based on the coefficients, analytical expressions of polarization dependent loss in fiber gratings were then deduced according to its deterministic and nondeterministic measurement principles. The given expression can precisely determine the polarization dependent loss (PDL) of the uniform fiber Bragg grating written in the isotropic or low birefringence fiber, and can also numerically simulate the approximate PDL result of Bragg uniform fiber grating written in the high birefringence fiber. The derived result agrees well with the existed experimental curve.