Cooperative dynamics and functions in a collective nonlinear optical element system

An optical ring cavity containing distributed nonlinear elements is proposed as a simple metaphorical model for investigating the dynamic properties of spatial chaos in a system far from thermal equilibrium. If the coupling between the elements is unidirectional, the stability of the disordered structure can be determined by the spatial Lyapunov exponent. This fact implies that spatial chaos is almost dynamically unstable and is replaced by spatiotemporal chaos. However, in the case of bidirectional coupling, the spatial chaos is self-induced over a wide range of the control parameter, which means that a memory function is formed cooperatively in the system. We predict several cooperative phenomena and describe their physical origin in terms of nonlinear dynamics. In particular, characteristics of spatial chaos applied to information storage are studied in detail. Applicability of predicted phenomena such as a cooperative all-optical switching, multivibrator operations, flip-flop operations, as well as spatial chaos memory, is discussed.