Coulomb Damped Relaxation Oscillations in Semiconductor Quantum Dot Lasers

We present a theoretical simulation of the turn-on dynamics of InAs/GaAs quantum dot semiconductor lasers driven by electrical current pulses. Our approach goes beyond standard phenomenological rate equations. It contains microscopically calculated Coulomb scattering rates, which describe Auger transitions between quantum dots and the wetting layer. In agreement with the experimental results, we predict a strong damping of relaxation oscillations on a nanosecond time scale. We find a complex dependence of the Coulomb scattering rates on the wetting layer electron and hole densities, and we show their crucial importance for the understanding of the turn-on dynamics of quantum dot lasers.