The dynamical behavior of a hybrid optical bistable system with a short delay is calculated numerically in detail. The quasi-periodic motion and frequency locking of the system are observed experimentally.
In a previous paper1an empirical and analytical study of instabilities in hybrid optical bistable systems was reported by us. At the end of that paper and in order to study the theory, a triangular voltage bias was added to the feedback, instead of the usual constant one. In that way the workline is displayed with the same slope, tg−1βIIN. Because the slope transmission ( dT dV ) was negative, the output, for a constant input, was periodic oscillations having a delay time larger the material response time. The nomenclature is explained in ref. 1.
In the linear instability analysis of the difference-differential equation which describes the dynamic behaviors of optical bistability with delayed feedback, introducing degree of stability S, which is defined as the ratio between relative variations of input and output intensities(1), we find that for long delay time instability condition is S≥2 and possible oscillation periods are approximately T ¯ = 2 T / ( 2 n + 1 ) but for short delay time the condition is S≥1 + πτ/2T and the periods are T ¯ = 4 T / ( 4 n + 1 ) . So the generation of instability for long delay time is easier than for short one, as shown in Fig.1.