Strong and weak chaos in networks of semiconductor lasers with time-delayed couplings

摘要

Nonlinear networks with time-delayed couplings may show strong and weak chaos, depending on the scalingnof their Lyapunov exponent with the delay time.We study strong and weak chaos for semiconductor lasers, eithernwith time-delayed self-feedback or for small networks. We examine the dependence on the pump current andnconsider the question of whether strong and weak chaos can be identified from the shape of the intensity trace,nthe autocorrelations, and the external cavity modes. The concept of the sub-Lyapunov exponent λ0 is generalizednto the case of two time-scale-separated delays in the system. We give experimental evidence of strong and weaknchaos in a network of lasers, which supports the sequence of weak to strong to weak chaos upon monotonicallynincreasing the coupling strength. Finally, we discuss strong and weak chaos for networks with several distinctnsub-Lyapunov exponents and comment on the dependence of the sub-Lyapunov exponent on the number of anlaser’s inputs in a network.