Nearly degenerate four-wave mixing investigation of period doubling in semiconductor lasers

The nearly degenerate four-wave mixing technique is used to investigate the physical origin of period doubling in the route toward chaos. This spectroscopic approach identifies resonantly enhanced nearly degenerate four-wave mixing processes as being responsible for the generation of subharmonic frequencies. The technique presented in the case of GaAlAs semiconductor lasers could be applied to the study of monomode instabilities occurring in any laser or bistable devices.