Dynamical behavior of semiconductor ring lasers

We present an asymptotic two-dimensional rate-equation model for single-longitudinal mode semiconductor ring lasers. An analysis of this rate-equation model predicts several regions of operation, showing monostability, bistability, alternate oscillations, tristability and excitability. These operation regimes are interpreted in the asymptotic two-dimensional phase-space and are experimentally demonstrated. In the region of excitability, the pulses emitted by an excitable (asymmetric) semiconductor ring laser are experimentally and theoretically characterized. Furthermore, we show that it is possible to mimic neural functionality by considering them in a coupled configuration.