全同弱光纤光栅阵列反射信号仿真计算与分析

Simulation and analysis of reflected signals in identical weak fiber Bragg grating arrays

全同弱光栅通过时分/波分混合复用时,光栅阵列中的阴影效应、多重反射等对反射信号会产生影响。对全同弱光纤光栅阵列所作的时域反射信号仿真计算和分析表明,阴影效应和多重反射不会引起光栅中心波长漂移,但会导致光栅中心波长处的反射强度降低。若阵列中的单个光栅的反射率较高,受阴影效应的影响,光栅阵列远端的光栅将可能检测不到,不能达到增加光栅复用数量的目的;但若单个光栅的反射率太低,则又会使阵列上的光栅的被测反射信号强度降低,从而增加了信号检测难度。

When identical weak grating arrays go through hybrid TDM/WDM,shadowing effect and multiple reflections in the grating arrays affect the reflected signals.This paper performs simulation calculation and analysis of the time domain reflected signals in the grating arrays.The shadowing effect and the multiple reflections will not cause the drift of the grating center wavelength,but may lead to the decrease of the reflection intensity at the grating center wavelength.If every single grating in the arrays possesses high reflectivity,owing to the shadowing effect,it may not be possible to detect the gratings at its distal end arrays,resulting in failure to increase the number of multiplexed gratings.However,when the single grating reflectivity is too low,the weak reflected signals in the grating array will increase the difficulty in signal detection.