A theoretical analysis and computer simulation of the threshold current den
sity j(th) and characteristic temperature T-0 of multiple quantum well lase
rs (MQWLs) are presented. Together with the spontaneous radiative recombina
tion, the Auger recombination and the lateral diffusive leakage of carriers
from the active region are included into the model. A first-principle calc
ulation of the: Auger recombination current is performed. It is shown that
the lateral diffusive leakage current is controlled by the radiative and Au
ger currents. When calculating the carrier densities, the electrons in the
barrier regions are properly taken into account. Redistribution of electron
s over the active region is shown to increase the threshold current conside
rably. The dependences of jth and To on temperature, number of QWs, cavity
length and lateral size are discussed in detail. The effect of lattice and
carrier heating on j(th) and T-0 is investigated and shown to be essential
at high temperature.