Design of optimal length low-dispersion FBG filter using covariance matrix adapted evolution
ABSTRACT The design of a low-dispersion fiber Bragg grating (FBG) with an optimal grating length using covariance matrix adapted evolution strategy (CMAES) is presented. A novel objective function formulation is proposed for the optimal grating length low-dispersion FBG design. The CMAES algorithm employs adaptive learning procedure to identify correlations among the design parameters. The design of a low-dispersion FBG filter with 25-GHz (or 0.2 nm in the 1550-nm band) bandwidth is considered. Simulation results, obtained using the codes available in public domain (the codes are available from the third author), show that the CMAES algorithm is more appropriate for the practical design of length optimized FBG-based filters when compared with the other optimization methods.
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ABSTRACT: 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.IEEE Photonics Technology Letters 04/2005; · 2.04 Impact Factor
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ABSTRACT: A rigorous analysis of the response of fiber Bragg gratings of finite length is presented. For the discrete grating model, we find necessary and sufficient conditions for the response to be realizable as a grating of finite length. These conditions are used to develop a general method for designing gratings with a prescribed length. The design process is divided into two parts. First, we find a realizable reflection spectrum which approximates the target spectrum. Once the spectrum is found, one can determine the associated grating profile by straightforward layer-peeling inverse-scattering or transfer matrix factorization methods. As an example, a dispersionless bandpass filter is designed and compared to the results when the layer-peeling algorithm is applied directly to a windowed impulse response. We also discuss potential applications to grating characterization including regularization and finding the absolute reflection spectrum from a measured, normalized version.IEEE Journal of Quantum Electronics 11/2003; · 1.83 Impact Factor
Conference Proceeding: Novel fibre Bragg grating design using multiobjective evolutionary algorithms[show abstract] [hide abstract]
ABSTRACT: A multiobjective evolutionary optimisation algorithm is applied to a fibre Bragg grating (optical filter) design problem. The design specified a dual wavelength filter with four required spectral characteristics - total bandwidth, peak separation, peak width and minimum transmission. Five parameters which described the apodised grating profile were used to define the search space and the transfer matrix method was used to numerically evaluate the transmission spectrum of candidate solutions. Various constraints on the search space were included in the design algorithm. Two separate selection schemes were tested, a distance based approach as used in the nondominated sorting genetic algorithm (NSGA-II) and a conglomerative clustering approach as used in the strength Pareto evolutionary algorithm (SPEA). Nondominated solutions are found and it is evident that particular objectives can be achieved more easily than others. Preliminary results are discussed and future work is introduced.Evolutionary Computation, 2003. CEC '03. The 2003 Congress on; 01/2004