Optimal design of segmented quasi-phase-matching SHG+DFG wavelength conversion structure based on hybrid genetic algorithm

Abstract

A hybrid genetic algorithm is proposed to optimal design the wavelength converter which using segmented grating structure and cascaded second-harmonic generation and difference-frequency generation process. Investigation of the influences of the structure parameters on conversion bandwidth and conversion response are carried out. High conversion efficiency, flat response and broad conversion bandwidth can be obtained simultaneously, by adding the segment number of QPM grating and optimizing the poling period of each segment. The utilizing of the hybrid genetic algorithm can not only make one obtain precise optimal results, but also shorten the simulation time significantly, so it is helpful to the practical design of the wavelength converters.