Stochastic synchronization and aperiodic stochastic resonance of a unidirectionally coupled single-mode optical system

The variational method is applied to a unidirectionally coupled single-mode optical system for the general characteristics of aperiodic stochastic resonance (ASR) and stochastic synchronization in the linear response background. It is shown that ASR in the low-frequency domain exists in all stable cases by means of coherence function, but the stochastic synchronization in the weak noise level exists only when the drive subsystem is bistable or multistable. However, the curve of correlation coefficient vs. the noise intensity exhibits ASR-like behavior only when the drive subsystem is monostable. The relaxation property of the drive subsystem is found to be responsible for these different characteristics.