In-plane electron dynamics and hot electron effects in a quantum cascade laser

A model of a quantum cascade laser in the near threshold regime is formed. The influence of the thermal population on the threshold current and the gain is estimated by the model. Subband populations and electron dynamics are solved within a rate-equation formalism derived from the non-stationary Boltzmann equation. The model offers a direct account of the dependence of the subband population on the current density and the dependence of the threshold current on the temperature. Very good agreement between the experimental results and our model is obtained.