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 σ, the homogeneous broadening Γ, and the interlevel relaxation time on the relaxation oscillations (ROs) is investigated. When the inhomogeneous broadening is dominant (Γ≪σ), the individual nanostructures in the ensemble exhibit independent ROs. In the case of significant homogeneous (Γ⩾σ) broadening, the quantum-dot ensemble exhibits collective, synchronized ROs, leading to a stronger intensity modulation and a larger turn-on delay.