Synchronized chaos and spatiotemporal chaos in arrays of coupled lasers

A subset of lasers in an array of coupled lasers can produce identical, synchronized, chaotic signals. Beyond a critical coupling strength, synchronization fails, and spatiotemporal chaos results. The transition to spatiotemporal chaos is signaled by spatial symmetry breaking. Quantitative measures of the transition from synchronized chaos are provided by Lyapunov exponents, sub-Lyapunov exponents, and the mutual information content.