GAIN DISPERSION AND SATURATION EFFECTS IN 4-WAVE-MIXING IN SEMICONDUCTOR-LASER AMPLIFIERS

This paper addresses four-wave mixing (FWM) in semiconductor laser amp lifiers from the point of view of a propagation problem, The gain disp ersion effect, i.e., the difference of the gain factors for the pump, probe and signal waves is shown to be significant in the case of large detunings >1 THz. It is given an analytical solution of the FWM probl em including gain dispersion and saturation effects, Considering the s aturation behaviour, it is shown that the linear gain factors for the different waves and the nonlinear susceptibilities associated with the different nonlinear effects must be characterized by different carrie r densities at transparency, A comparison of our theory with a numeric al model, with previous approaches and with experimental data is given .