Synthesis of an Optical Period Chirp from a Physical Bragg Period Chirp Using Direct Tabu Search Algorithm

Abstract

In this paper, a hybrid Direct Tabu Search (DTS) is used to synthesize an equivalent chirp in the refractive index and a chirp in the centre wavelength of a Fiber Bragg Grating (FBG) from its original physical grating period chirp. The synthesis method involves the use of the Transfer Matrix Method (TMM) for calculating the spectral response of a FBG. Direct search based strategies are used to direct a tabu search. These strategies are based on a new pattern search procedure called Adaptive Pattern Search (APS). In addition, the well known Nelder-Mead (NME) algorithm is used as a local search method at the final stage of the optimization process. The method is applied on a gaussian chirped fiber Bragg grating and a gaussian multi channel fiber grating. The numerical simulations show good agreements between original spectral characteristics and reconstructed ones.