Superlinear dependence of gain on current density in GaAs injection lasers

Measurements of threshold-current density and incremental efficiency on homostructure and heterostructure GaAs lasers show an increasingly superlinear dependence of gain g on current density J with increasing temperature. The index n in the relation g J^n satisfies the relation n = 1 + (kT/Eₓ) ^2^1/2 where E t is a measure of the band-tail depth.