A novel 80 km dispersion-compensation 8x100GHz comb-equalizer for fiber optical parametric amplifier

A novel dispersion-compensation superstructure fiber Bragg grating (SFBG) based comb gain equalizer for fiber optical parametric amplifier (FOPA) is proposed. It is characterized by its eight-channel 100GHz DWDM-channel separations and 80 km dispersion compensation function. The object reflectivity spectra of gain equalizer are calculated in two parts independently. Inner channel part for every channel is designed according to the gain spectrum of fiber OPA. Inter-channel part is calculated with Gaussian hypergeometric function (-0.5dB bandwidth 0.1nm, -45dB bandwidth 0.3nm) to obtain slower rising and descending edges than the simply zeroed case. Then the SFBG is designed with layer-peeling inverse scattering technique. Simulation results show that this SFBG satisfies all requirements. Using this SFBG as comb gain equalizer, the gain of fiber OPA is flattened in every channel to within ±0.4dB among 8 ITU-T regulated channels, with 80 km dispersion compensated.