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.