TEMPERATURE-DEPENDENCE OF THRESHOLD CURRENT-DENSITY J(TH) AND DIFFERENTIAL EFFICIENCY ETA(D) OF HIGH-POWER INGAASP/GAAS (LAMBDA=0.8-MU-M) LASERS

An experimental and theoretical study on temperature dependence of the threshold current density Jth and differential efficiency ηd for the InGaAsP/GaAs laser diodes emitting at λ=0.8 μm was performed. Threshold current density Jth increases and differential efficiency ηd decreases as temperature is increased mainly because of thermal broadening of the gain spectrum. However, the measured temperature dependence of Jth and ηd could not be explained when only this effect was considered. In this letter, the temperature dependence of momentum relaxation rate /τ of carriers was investigated by performing the photoluminescence study. At high temperature, increase of the momentum relaxation rate /τ leads to reduction of the gain and mobility and increase of the optical loss, causing higher Jth and lower ηd as experimentally observed. The resulting theoretical model provides a good explanation for the mechanism of the increase of Jth and decrease of ηd. © 1995 American Institute of Physics.