Thermal analysis of high-performance mid-infrared quantum cascade lasers

We investigated theoretically the thermal characteristics of quantum cascade lasers (QCLs) based on InGaAs/AlInAs/InP materials operating at lambda ~ 4.6 mum. By using a steady-state two dimensional (2D) heat dissipation model, the maximum internal temperature, heat flow pattern, and thermal conductance were obtained for the different device geometries with epilayer-up and down bonding scheme. As the heatsink temperature increases, the maximum internal temperature increases. For 10 mum times 4 mm epilayer-down bonded laser with diamond submount and InP waveguide, a high thermal conductance of G_th = 619.7 W/K-cm² at room temperature was obtained.