Effects of ultrafast processes on frequency converters based on four-wave mixing in semiconductor optical amplifiers

Abstract

We show the effect of the ultrafast optical nonlinear interactions on the efficiency of a frequency converter based on four-wave mixing (FWM) in semiconductor optical amplifiers (SOAs). The ultrafast nonlinearities generate a dip of a few decibels in the down-conversion sideband of the conversion efficiency at detuning higher than 1 THz. The frequency detuning at which the minimum occurs depends on the device length and on the pump wavelength. The presence of the minimum of the efficiency affects the design of amplifiers specifically optimized for frequency conversion by FWM.