RELAXATION-OSCILLATION-INDUCED CHAOTIC INSTABILITIES IN MODULATED EXTERNAL-CAVITY SEMICONDUCTOR-LASERS

We theoretically examine the consequences of modulating an external-cavity semiconductor laser around its mode-locking resonant frequency. When the modulation frequency is below resonance, the laser exhibits a three-frequency route to chaos. When the modulation frequency is above resonance, the laser oscillates in two- and three-frequency states. The chaotic instability is a result of the nonlinear interaction of three periodic modes of the laser system. These modes are dynamical manifestations of the composite cavity mode-locking resonance, the applied field that is due to the modulation, and the laser relaxation oscillation.