Nonlinear Dynamics in Semiconductor Lasers - Abstract

Quintero Quiroz, Carlos

Experimental study of transitions between locking regimes in an optical system with weak periodic forcing

The entrainment phenomenon, by which an oscillator adapts its natural rhythm to an external signal, has been observed in physics, chemistry, biology, etc. Recent attention has focused on the optimal conditions for entraining an oscillator to a weak external periodic signal. Here we use an experimental setup consisting of a semiconductor laser with optical feedback, as a testbed to study entrainment phenomena. The laser operates in the so-called low frequency fluctuations (LFFs) regime, in which the laser intensity displays apparently random spikes citetiana-alsina:2010. Our goal is to experimentally identify and characterize the transitions between different locking regimes, when a weak periodic signal modulates the laser current. We investigate the transition between 1:1 locking (the frequency of the optical spikes is equal to the modulation frequency) and 2:1 locking (the spike frequency is half the modulation frequency), as well as higher order, noisier locking regimes. The experimental control parameters are the amplitude of the weak signal, its frequency, and the control parameter of the laser (the dc value of the pump current, which controls the natural frequency of the spikes). Three measures are used to quantify the entrainment quality and to identify the boundaries of the different locking regimes. We also discuss how the laser responds to a weak non-periodic signal, when it operates at the boundary between locking regions. bibitemtiana-alsina:2010 J. Tiana-Alsina, M.C. Torrent, O.A. Rosso, C. Masoller, J. Garc'ıa-Ojalvo, “Quantifying the statistical complexity of low-frequency fluctuations in semiconductor lasers with optical feedback”, Phys. Rev. A 82(1), 013819 (2010).