Optical phase conjugation in laser diodes subject to strong probe injection power

Nearly degenerate four-wave mixing in semiconductor lasers is experimentally studied for different probe injection powers. It is shown, in accordance with theoretical predictions, that the reflectivity efficiencies of probe and conjugate waves demonstrate significantly different behaviour for strong probe injection power, compared with small probe power. Nearly uniform conversion efficiency of order 20-30 dB for frequency detuning up to 3 GHz is achieved at ~0.8 μW launched probe power