Optimization for maximum Raman frequency conversion in supercontinuum sources using genetic algorithms

Abstract

A frequency convertor based on the soliton self-frequency shift by the supercontinuum generation is obtained by optimization of only three parameters of a Ti:Sapphire laser pulse, namely, carrier wavelength, peak power and time duration. The frequency conversion is performed and calculated by simulating the propagation of the pulse in a simple piece of $25$ cm long commercial photonic crystal fiber pumped by the femtosecond Ti:Sapphire laser, whose only pre-requisite is to exhibit the standard supercontinuum. The resulting spectral broadening has a maximum spectral conversion in the anomalous region just by playing with the three realistic controllable parameters. Optimization is performed using pre-defined functions of genetic algorithms. Our results indicate that the efficiencies of Raman conversion achieved by merely optimizing the pulse parameters in a commercial fiber are comparable with those obtained in more elaborated Raman convertor devices.