A self-consistent theory for semiconductor lasers, in which plasma and lattice temperatures are treated as two independent variables, is presented. This theory consists of a set of coupled equations for the total carrier density, field amplitude, and plasma and lattice temperatures with the coupling that is due to phonon-carrier scattering and to the band gap's dependence on lattice temperature. The self-consistent theory is then employed to study thermal effects in vertical-cavity surface-emitting lasers. We first investigate the plasma heating by solving the stationary (cw) solution of the set of equations with a fixed lattice temperature. The solution is studied systematically with respect to different parameters for both bulk and quantum-well media. Significant plasma-heating effects are found. These include the carrier-density dependence on pumping, decrease of input–output efficiency, dependence of the cw frequency shift on pumping, and a pronounced Pauli-blocking effect that is due to plasmaheating. Furthermore, we solve the whole set of equations, including that for lattice temperature. We show that the output power is strongly saturated or switched off with an increase of pumping. Details of the saturation depend on the position of the cavity frequency in the gain spectrum and on the heat transfer rate from the lattice to the ambient.
© 1995 Optical Society of AmericaPDF Article