Semiconductor Ring Lasers (SRLs) are a modern class of semiconductor lasers whose active cavity is characterized by a circular geometry. SRLs have attracted attention for two main reasons. On the one hand, SRLs are promising components in photonic integrated circuits due to their potential in applications such as all-optical memories and data processing. On the other hand, SRLs are prototypes for the large class of Z2 symmetric systems encountered in a wide number of physical systems.
This talk addresses the stochastic and nonlinear dynamical behavior of a SRL operating in single-longitudinal and single transverse mode. Emphasis is put on the experimentally observable effects that are a consequence of the ring symmetry and that can be theoretically addressed in a device-independent way by investigating the invariant manifolds of the system.
It is shown how to experimentally control the internal parameters of the SRL such as the mode coupling and how to break the ring symmetry in a controllable and reversible way. Bistability and multistability between three coexisting operating states in the symmetric SRL are disclosed. In these regions, non-Arrhenius features appearing in the residence time distribution as well as the anatomy of the mode-hopping events are discussed.
Finally, when the symmetry of the system is weakly broken, excitability is revealed. The response of the SRL to optical trigger pulses is characterized and we show that the phase difference between the fields plays an important role in determining the excitability threshold. A novel mechanism for exciting multiple consecutive pulses using a single trigger pulse is also discussed. Finally, when excitations are triggered by noise, the variety of pulse shapes is characterized theoretically and compared with experiments.