Bifurcations of a DFB Laser with Short Optical Feedback: Numerical Experiment

We have applied a comprehensive simulation tool for multisection DFB lasers to systematically investigate bifurcations caused by combining a single mode DFB laser with a feedback section. Strength and phase of the optical feedback are considered as main bifurcation parameters. The recording of output power, optical and power spectra and carrier density yield evidence of fold bifurcations of stationary states as well as subcritical and supercritical Hopf bifurcations towards self-pulsations. Furthermore, a homoclinic bifurcation is detected and indications for a fold of limit cycles are observed in qualitative agreement with a bifurcation diagram very recently calculated with path following techniques under simplifying assumptions. The present simulations show that these bifurcations are stable with respect to these approximations. They offer a method how the bifurcations can be determined experimentally.