Study On Chaotic Control Of Bragg Acousto-Optic Bistable System

One of the most important achievements in nonlinear science is the cognition of chaos. The purpose of chaos research is to control and make use of it. Optical chaos is a branch of chaos domain. Acousto-optic bistable (AOB) system is studied extensively in optical chaotic control research for its many advantages just like simple device and easy to achieve. As the development of this filed, chaos control and its application are becoming more and more extensive. The research of AOB's chaotic control has also got a breakthrough.In this paper, a model on the base of Bragg AOB system is constructed, and two control methods for AOB's chaotic state are proposed. These two methods are external perturbation feedback control and delay feedback perturbation control. In the control of external perturbation feedback, the changes of system state and Lyapunov exponent with feedback intensity have been analyzed. The effect of noise and chaotic degree to state evolvement are also discussed. The results of numerical simulation show that the system can be controlled to different stable periodic orbits by choosing feedback intensity properly. The system also has the ability of anti-jamming when the noise is small. This method uses invariable signal instead of periodic or temporal perturbation, which makes experiment easy to achieve. Also, the system can be controlled in a large area, that means not only can it be controlled to the lower periodic orbit, but also be controlled to the higher stable orbits.Taking Logistic map, AOB and Henon map as examples, the delay feedback perturbation control uses especial feedback signal which is obtained by subtracting delay signal from output signal. The state evolvement of system is discussed when the control interference signal acting on partial system and holistic system respectively. The influence of system by using method of continuous control and occasional control is also analyzed. By means of numerical simulation, the system can be controlled to different stable periodic orbits by choosing feedback intensity properly. The occasional feedback control gains the advantage over other methods for its less control cost and much more control area. Also the steady period of system is the integral multiple of the occasional feedback period. On the other side, when the occasional feedback period is higher, the system will lose the control of lower stable periodic orbits by using this method.