Phase effect of two coupled periodically driven Duffing oscillators

We consider the effect of phase difference in mutually coupled chaotic oscillators with a large coupling strength. The phase difference destroys the synchronization of chaotic oscillators, and lag synchronization is observed. For large difference, it even takes the coupled oscillators from chaotic motion to regular motion. For small frequency detuning of two driving forces, stochastic breathing, bifurcation delay, and stochastic transition are observed. The mutually coupled periodically driven Duffing oscillators are taken as a numerical example. [S1063-651X(98)05911-X].