Temperature dependence of threshold current density J_(th) and differential efficiency η_d of high-power InGaAsP/GaAs (λ=0.8 μm) lasers

摘要

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