Characteristics of the optical-frequency conversion in a semiconductor laser

A small signal analysis is presented for optical-frequency conversion using nearly degenerated four-wave mixing (FWM) in a semiconductor laser. The nearly degenerate FWM is mainly introduced by the carrier beating at the detuning frequency of the pump and the probe waves. Generally speaking, the influence of the nonlinear gain saturation on the frequency conversion efficiency is very small compared with that of the carrier density beating. However, the conversion efficiency is damped by the nonlinear gain saturation at higher bias current. The frequency conversion efficiency and the probe transmissivity are almost symmetrical with respect to the zero detuning frequency. The bandwidth of the converted signal is governed by the relaxation resonance frequency of the laser. A definition of the conversion. The theoretical results agree with experiments