Abstract

We consider the spontaneous emergence of organized behavior and spatiotemporal chaos in an array of coupled semiconductor lasers. In the absence of coupling, each laser in the array exhibits a constant, steady state output intensity in response to a constant input pump current. The individual uncoupled lasers do not exhibit any interesting instabilities such as chaos. In the presence of coupling, the constant steady state can lose its stability with the result that nontrivial spatiotemporal complexity emerges. The nature of the spatiotemporal dynamics depends on the strength of the coupling between adjacent lasers. For low coupling strengths there is a stable steady state which is constant in time and in which the fields in adjacent elements have nearly equal amplitudes and a phase difference close to pi. As the coupling is increased a Hopf bifurcation to a spatially ordered and temporally periodic output is obtained. Further increases in coupling strength lead to full blown spatiotemporal chaos. For even larger coupling strengths we have observed an interesting intermittency featuring bursts of chaotic activity in the amplitudes. Associated with these bursts of chaos are discontinuous jumps in the relative phase. These phase jumps are organized in a steplike fashion in a manner reminiscent of a devil′s staircase.

© 1989 Optical Society of America