Rate equations for the diode laser and their applicability area

Taking into account spontaneous emission by adding its intensity in the form of a constant term to the laser emission intensity in rate equations is shown to be an inadequate approach. The use of rate equations without equations for phases of waves is limited to problems in which light is characterised by its total intensity, without its spectral composition. Such equations are incapable of adequately modelling the emission spectrum of diode lasers.