Two-stage hybrid optimization of fiber Bragg gratings for design of linear phase filters.
We present a new hybrid optimization method for the synthesis of fiber Bragg gratings (FBGs) with complex characteristics. The hybrid optimization method is a two-tier search that employs a global optimization algorithm [i.e., the tabu search (TS) algorithm] and a local optimization method (i.e., the quasi-Netwon method). First the TS global optimization algorithm is used to find a "promising" FBG structure that has a spectral response as close as possible to the targeted spectral response. Then the quasi-Newton local optimization method is applied to further optimize the FBG structure obtained from the TS algorithm to arrive at a targeted spectral response. A dynamic mechanism for weighting of different requirements of the spectral response is employed to enhance the optimization efficiency. To demonstrate the effectiveness of the method, the synthesis of three linear-phase optical filters based on FBGs with different grating lengths is described.
Zheng
Rui Tao
RT
Photonics Research Center, School of Electrical and Electronic Engineering, Nanyong Technological University, Singapore 639798.
Ngo
Nam Quoc
NQ
Le Binh
Nguyen
N
Tjin
Swee Chuan
SC