Temperature Analysis of Threshold Current in Infrared Vertical-Cavity Surface-Emitting Lasers

The temperature dependence of threshold current I th in vertical-cavity surface-emitting lasers (VCSELs) can be approximated by the equation I th (T)=alpha+beta(T-T min ) 2 , where T min is the temperature of lowest I th ,alpha and beta are parameters, and temperature is T. We compare the temperature dependence of threshold current in VCSELs with GaAs, InGaAs, and strain compensated InGaAs-GaAsP quantum wells. From our analysis we find the coefficient beta is related to the gain properties of the quantum well, and is shown to serve as a benchmark for the VCSEL temperature sensitivity. The incorporation of strain-compensated high-barrier GaAsP layers in the active region of 980-nm VCSELs is demonstrated to reduce the threshold dependence on temperature