Influence of excess carriers on the permittivity of GaAs at the frequency of radiative transitions in injection lasers

A change in the resonance frequencies of the Fabry-Perot resonator of a GaAs laser diode with increasing pump current was detected and investigated. The value of δε/δN (e is the permittivity and N is the density of free electrons) was 2.6×10cm^–20 cm³ when the current density was 15 kA/cm², temperature was 300°K, and wavelength was about 901 nm.