Duty cycle variation methods for Bragg gratings: comparative study and optimal design

Abstract

An analysis of spectral response apodization by duty cycle methods for gratingassisted optical filters is presented. The study is performed for the case of co-directional couplers, Bragg reflectors and mirrors. The modeling results show that the supersymmetric duty cycle (SDC) modulation method, initially considered for Parity-Time symmetric gratings [JSTQE 22(5), 35-41 (2016)], performs better than the other methods. An analytical approach to the transfer matrix of the modulated grating explains the better performance of the SDC method.