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Rogue waves are devastating extreme events that occur in many natural systems, and a lot of work has focused on predicting and understanding their origin. In optically injected semiconductor lasers rogue waves are rare ultra-high pulses that sporadically occur in the laser chaotic output intensity. Here we show that these optical rogue waves can be predicted with long anticipation time, that they are generated by a crisis-like process, and that noise can be employed to either enhance or suppress their probability of occurrence. By providing a good understanding of the mechanisms triggering and controlling the rogue waves, our results can contribute to improve the performance of injected lasers and can also enable new experiments to test if these mechanisms are also involved in other natural systems where rogue waves have been observed. © 2013 American Physical Society.

Rogue waves are devastating extreme events that occur in many natural systems, and a lot of work has focused on predicting and understanding their origin. In optically injected semiconductor lasers rogue waves are rare ultra-high pulses that sporadically occur in the laser chaotic output intensity. Here we show that these optical rogue waves can be predicted with long anticipation time, that they are generated by a crisis-like process, and that noise can be employed to either enhance or suppress their probability of occurrence. By providing a good understanding of the mechanisms triggering and controlling the rogue waves, our results can contribute to improve the performance of injected lasers and can also enable new experiments to test if these mechanisms are also involved in other natural systems where rogue waves have been observed., Peer Reviewed, Postprint (published version)

Experimental observations of rare giant pulses or rogue waves were done in the output intensity of an optically injected semiconductor laser. The long-tailed probability distribution function of the pulse amplitude displays clear non-Gaussian features that confirm the rogue wave character of the intensity pulsations. Simulations of a simple rate equation model show good qualitative agreement with the experiments and provide a framework for understanding the observed extreme amplitude events as the result of a deterministic nonlinear process., Peer Reviewed, Postprint (published version)

We study, both experimentally and numerically, a system of two coupled semiconductor lasers in an asymmetric configuration. A laser subject to optical feedback is bidirectionally coupled to a free running laser. While maintaining the coupling strength, we change the feedback rate and observe a transition from highly correlated low-frequency fluctuations to episodic synchronization between dropouts and jump-ups. Our results resemble those obtained recently in a unidirectionally coupled system [Buldú et al., Phys. Rev. Lett. 96, 024102 2006].

We study the synchronization of logistic maps in a one-way coupling configuration. The master system is coupled to the slave system with a delay n1, and the slave is a delayed logistic map with a delay n2. We show that when the slave system has no delay (n2=0), perfectly synchronized solutions exist for strong enough coupling. In these solutions the slave variable y is retarded with respect to the master variable x with a retardation equal to the delay of the coupling [y(i+n1)=x(i)]. When n2¿0, a regime of generalized synchronization is observed, where y(i+n1) is synchronized with x(i), but not completely, since the master and the slave systems obey different maps. We introduced a similarity function as an indicator of the degree of synchronization and, using a noisy master source, distinguished synchronization from noise-induced correlations., Peer Reviewed, Postprint (published version)