Gain in injection lasers based on self-organized quantum dots

The analytical form of the dependence of the gain on pump current density f or lasers with an active region based on self-organized quantum dots is der ived in a simple theoretical model. The proposed model is shown to faithful ly describe experimental data obtained for laser diodes based on InGaAs qua ntum dots in an AlGaAs/GaAs matrix, as well as InAs quantum dots in an InGa As/InP matrix. The previously observed gain saturation and switching of the lasing from the ground state to an excited state of the quantum dots are s tudied. The influence of the density of quantum-dot arrays on the threshold characteristics of lasers based on them is examined on the basis of this m odel. (C) 1999 American Institute of Physics. [S1063-7826(99)01302-2].