Particle swarm optimization for the design of low-dispersion fiber Bragg gratings

We propose a novel formulation of the objective function for the design of fiber Bragg grating (FBG)-based filters with respect to the given design specifications, instead of matching the desired magnitude and phase responses of the filter at each wavelength of the operating window that has commonly been used in previous works on FBG synthesis. The desired reflective spectrum and group delay characteristics of a filter are predefined using six design specifications. Particle swarm optimization (PSO) technique is employed here to find an optimum index modulation profile that meets the target design. To demonstrate the effectiveness of the PSO algorithm and the novel formulation of the objective function, an optimal design of a low-dispersion FBG-based filter with 0.2-nm bandwidth (or 25 GHz in the 1550-nm window) for three desired values of the maximum reflective power is presented.