We study chaotic synchronization in degenerate optical parametric oscillators(DOPOs) by hyperchaotic signal modulating parameter.It shows that synchronization or inversed synchronization is realized in two or more chaotic systems by adjusting modulating coefficient as the maximum condition Lyapunov exponent(MCLE) of the system is negative.It is observed that the synchronization states depend on initial conditions and modulating coefficients.Under certain initial conditions,the synchronization state shows spontaneous mutation at some modulating coefficients.

The suppression of spatiotemporal chaos is realized by using variable feedback techniques in coupled bistable map lattice systems.Numerical simulations indicate that the chaos in a bistable map system and the spatiotemporal chaos in a coupled bistable map lattice system could be suppressed to the fixed point or the periodic orbits by using different feedback techniques and strengths.In addition to the fixed point of a local bistable map system the feedback control method does not require a priori dynamics information of the coupled bistable map lattice system.The method appears useful in controlling turbulence of coupled bistable map lattice systems.

At first, output equations of coupled-Lorenz lasers are changed into coupled Lorenz Model equations with coupling factor β, and the instability and chaos of the output are stimulated in numerical value, the average output power of coupled Lorenz lasers in self-pulse and chaotic regions is studied at last in this paper.