Nonlinear dynamics of a semiconductor laser with filtered optical feedback and the influence of noise

We investigate the influence of quantum noise on the highly complex nonlinear dynamics that arise in a single-mode semiconductor laser subject to filtered optical feedback. Our numerical study, which utilizes rate equations that are augmented by Langevin noise terms to account for the spontaneous-recombination noise, shows that for relatively broad filters the noise may lead to qualitatively different dynamics than predicted by a deterministic analysis. In particular, we find that certain attractors that are predicted in the absence of noise may no longer be available when the effects of noise are correctly incorporated. For narrow bandwidth filters we demonstrate optical-injection-like behavior and identify locking of the semiconductor laser to the relaxation oscillation side peaks. In general, the results indicate that shot noise in the laser can influence the dynamics quite substantially.