Abstract

Non-linear delay differential systems (NDDS) are well known to exhibit chaotic dynamics of high complexity in an infinite dimensional phase space. Actually, their chaotic attractor dimension is finite, but it is related to the ratio T/τ (T: delay, τ: response time). Experimental attractor dimensions greater than 100 are achieved. The first such systems were studied by Mackey and Glass in biological system, and then in optics, Ikeda[l] explored similar chaotic behaviour in a non-linear ring cavity. More recently, these dynamics have been investigated for secure optical communication systems using chaos. Our group proposed different experimental setups, all of them using a single delay first order NDDS for the generation of chaos. Nevertheless, it has been recently shown that single delay NDDS may be characterized from the observation and analysis of the chaotic time series, despite the high attractor dimension. On the other hand, two (or more) time delays appeared to be robust against the time series analysis technics. We present here the first experimental results concerning a two time delay NDDS, in terms of an experimental bifurcation diagram and a numerical investigation of the Lyapunov dimension.

© 2001 EPS