Optimizing fiber Bragg gratings using a genetic algorithm with fabrication-constraint encoding

We propose an advanced genetic algorithm (GA) to design fiber Bragg gratings (FBGs) with given fabrication constraints. Our GA is enhanced by a new Fourier-series-based real-valued encoding to obtain more degrees of freedom and a rank-based fitness function. The new GA enables us to remove phase shifts in the gratings. The designed minimum-dispersion bandpass grating has a dispersion of /spl plusmn/28 ps/nm in the 0.33-nm flat-top passband. The grating is fabricated using a phase mask without phase shift.