According to the ideal approximation of the coupled-mode theory,the Bragg equation and the peak reflectivity expression of the fiber Bragg grating are derived.

• 根据理想模展开下的耦合模方程,对光纤布拉格光栅的峰值反射率公式进行了数学推导,得到了布拉格光纤光栅的光谱反射率表达式。