Nonlinear Dynamics in Semiconductor Lasers - Abstract

Panayotov, Krassimir

Nonlinear dynamics of VCSELs and QD lasers induced by optical injection

First, we briefly review the new features to the nonlinear dynamics of VCSELs induced by optical injection that are due to the lack of polarization anisotropy and to multiple transverse mode operation. We demonstrate a new Hopf bifurcation on a two-polarization-mode solution that delimits the injection locking region and a new resonance tongue for large positive detunings that is due to polarization switching and injection locking of first-order transverse mode. Next, we discuss how the presence of an excited state impacts the dynamics of an optically injected quantum-dot laser. Mapping of the bifurcations in the plane frequency detuning vs. injection strength shows that the relaxation rate scales the regions of locking and single- and double-period solutions. Within the regions of time-periodic solutions, close to the saddle-node bifurcation boundary, dynamics resemble excitable pulses as a result of a bottleneck phenomenon. The interpulse time follows an inverse square root scaling law as a function of the detuning. In the presence of noise, close to the locking region, the interpulse time follows a positively skewed normal distribution. For the case of quantum dot laser lasing simultaneously from the ground and excited states and optical injected into the ground-state mode alone, we demonstrate the generation of regular picosecond pulses and pulse packages in the intensity of the excited-state mode. We attribute this dynamics to an intrinsic gain switching mechanism where the relaxation time is modulated by the oscillations in the occupation of the ground and excited energy states.