Optical instabilities in a nonlinear Kerr medium

Abstract

Instabilities and self-oscillation in systems containing an optical Kerr medium are studied in detail. Nonlinear interactions, both within and without a cavity, are discussed. Instability thresholds and frequencies of self-oscillation are treated as a gain-feedback process. A detailed investigation of the instabilities in a high-finesse nonlinear ring cavity shows that both Ikeda instabilities and bistability are obtained in a rather limited regime of detuning. In most of the detuning range, the system exhibits period-τ oscillations. Counterpropagating waves in a Kerr medium are shown to become unstable above a certain threshold intensity. This results in a system that is equivalent to a Raman-like laser that is being excited in the distributed-feedback structure generated by the two waves. A qualitative description of harmonic generation and period doubling, based on wave-mixing processes, is also presented.