Influence of carrier lifetimes on the dynamical behavior of quantum-dot lasers subject to optical feedback

We examine changes in the dynamics of a semiconductor quantum-dot (QD) laser subject to optical feedback that correlate to changes in the QD laser band structure. By employing a microscopic model for the carrier-carrier scattering processes between the QDs and the carrier reservoir we are able to tune the carrier lifetimes in the QDs, e.g., by modifying the QD confinement energies or the pump current. By using numerical continuation methods as well as asymptotic theory we demonstrate that the feedback sensitivity crucially depends on these lifetimes through the damping of the turn-on oscillations, and small lifetimes on the order of this relaxation time scale lead to an increased feedback resistivity. Thus intelligent band structure engineering can lead to stable continuous wave operation of the laser over a large parameter range.