How a quantum-dot laser turns on

The turn-on dynamics of quantum-dot lasers is modeled theoretically. The impact of the-so far technologically inevitable-inhomogeneous broadening sigma, the homogeneous broadening Gamma, and the interlevel relaxation time on the relaxation oscillations (ROs) is investigated. When the inhomogeneous broadening is dominant (Gamma much less than sigma), the individual nanostructures in the ensemble exhibit independent ROs. In the case of significant homogeneous (Gamma greater than or equal to sigma) broadening, the quantum-dot ensemble exhibits collective, synchronized ROs, leading to a stronger intensity modulation and a larger turn-on delay. (C) 2000 American Institute of Physics. [S0003-6951(00)02536-5].