Electrical Model of the Injection Laser

The simplest electrical model of the injection laser assumes that the active layer, the layer in which spontaneous and stimulated radiative recombination take place, is a homogeneous layer. The only parameters of such an electrical model are the thick¬ ness of the active layer, and the electron and hole concentrations and quasi-Fermi levels. If such a model is combined with an optical model with no k-selection rule,1one obtains reasonable agreement with experimental threshold current densities, particularly if energy band tails are taken into account.2The theory, however, predicts a superlinear relation between gain constant and current density near room temperature, while the observed relation is linear.3 Copyright © 1968 by The Institute of Electrical and Electronics Engineers, Inc.