An apodized optimization methods for phase shift sampled fiber Bragg grating

The sampled fiber Bragg grating (SFBG) with phase shifting technique is prevalently applied in dense wavelength division multiplexing (DWDM) system. In this paper, based on coupled-mode theory, the reflection spectrum of phase-shift sampled fiber Bragg grating (PS-SFBG) is numerically calculated with transmission matrix method, and the optimization methods are given to eliminate the side-lobe disturbance in the spectrum. During the process, as the phase shift is inserted into SFBG, the side-lobe disturbance increases remarkably. To solve this problem, the optimization method which is to cite an envelope apodization function to the index refraction is presented in this paper. Besides, several apodization functions are numerically calculated and compared. Then, an 8 channel PS-SFBG model optimized by the apodization function is founded which could be a theoretical guidance and a reference for the practical application in the DWDM system.