Stochastic resonance in a system of coupled chaotic oscillators

Noise-free stochastic resonance is investigated numerically in a system of two coupled chaotic Rossler oscillators. Periodic signal is applied either additively or multiplicatively to the coupling term. When the coupling cons tant is varied the oscillators lose synchronization via attractor bubbling or on-off intermittency. Properly chosen signals are analyzed which reflect the sequence of synchronized (laminar) phases and non-synchronized bursts in the time evolution of the oscillators. Maximum of the signal-to-noise ra tio as a function of the coupling constant is observed. Dependence of the s ignal-to-noise ratio on the frequency of the periodic signal and parameter mismatch between the oscillators is investigated. Possible applications of stochastic resonance in the recovery of signals in secure communication sys tems based on chaotic synchronization are briefly discussed.