Characterization of the chaos generated by semiconductor lasers subject to electro-optical and all-optical feedback

We characterize the chaotic dynamics of semiconductor lasers subject to either optical or electro-optical feedback. This characterization is relevant for secure optical communications based on chaos encryption. In particular, we compute as function of system parameters the following quantifiers: Lyapunov spectrum (which measures the rate at which the distance between infinitesimally close solutions increases in time), the Kaplan-Yorke dimension (conjectured to be equal to the information dimension which measures the amount of information needed to locate the system in phase space with infinitesimal accuracy) and the Kolmogorov-Sinai entropy (which measures the average loss of information rate, or equivalently is inversely proportional to the time interval over which the future evolution can be predicted).