说明：  用于模拟光纤光栅(FBG)的反射特性和时延特性,特别是用于模拟各种切趾包络下光纤光栅的反射和时延特性。
(Used to simulate the fiber Bragg grating (FBG) of the reflective properties and delay properties, especially for simulation of various apodization envelope under the fiber grating reflection and delay characteristics.)