Mitigation and suppression of rare events in weakly coupled lasers

Abstract

We consider an asymmetric laser system which displays mixed-mode oscillations and hyperchaos. This system consists of two laser oscillators which are weakly and bidirectionally coupled, where the asymmetry is induced by a mismatch between the laser pump parameters. The coupling scheme via saturable absorbers, however, is built up with a beam combining process which incorporates the electric fields of both laser oscillators. This procedure, which is relevant in semiconductor and solid-state lasers, is implemented in the present molecular laser model.In our numerical simulations and time series analysis we show that for small enough coupling strength, below the chaotic phase synchronization threshold, the asymmetric laser system displays extreme rare events in one of the lasers whose occurrence can be mitigated and suppressed by optical feedback. These episodes are outliers in the time series from the laser intensity and the return time intervals, and are reminiscent of Dragon-Kings. We estimate the correlation dimensions and Lyapunov exponents from the time series, which suggest the ubiquity of hyperchaotic dynamics irrespective of the occurrence or lack of extreme rare events in these time series.