The Internal Parameters of Injection Lasers

The phenomenological theory of injection lasers is considered, the physical meaning of the internal parameters is discussed, and the debatable character of some published data is noted. The internal parameters are measured for diffused GaAs laser diodes. As it follows from theory and experiment, the dependences of the maximum optical gain k on the current densityj and of the threshold j(t) on the losses k(1) are expressed by the formulae k = beta (j-j(0)) and j(t) = j(0) + beta(-1) k(1). The onset of laser action does not stabilize but only slows down the increase of spontaneous and non-radiative recombination rates with increasing diode current. The luminescence power in absolute units, the gain spectrum, and the difference between electron a, nd hole quasi-Fermi levels in a. GaAs injection la. ser arc determined. Optimum laser conditions are discussed.