Active Region Of Quantum Cascade Laser Research Articles

Investigation of Subband Electron Temperatures of Quantum Cascade Lasers

The electron temperature of each subband is the key to understanding the characteristics of quantum cascade lasers (QCLs). We show herein a method, based on the particle swarm optimization algorithm, to obtain the electron temperature of the conduction band in the active region of QCLs. Accurate subband electron temperatures at room temperature, low temperature, and under various external electric fields are obtained. Furthermore, we discuss the variation and distribution of subband electron temperature that occurs during the operation of QCLs. The laser gain and I–V curves are obtained from the subband electron temperature. A comparison of these results with experimental results confirms that consideration of the subband electron temperature can improve our understanding of QCLs.

Thermal Analysis of InAs/AlSb Short Wavelength Mid-IR Quantum Cascade Lasers

We present the effects of hetero-interfaces and major key parameters on the thermal behaviors and performance of short wavelength mid-IR InAs/AlSb quantum cascade lasers (QCLs). We use a finite element method (FEM) with commercial software, ANSYS, to simulate the heat dissipation in QCLs in cw operation mode with an epilayer-down mounting package. The thermal performance is characterized by the temperature increase ΔT (self-heating effect) between the active region of QCLs and the heatsink. Results show that (1) the self-heating effects of InAs/AlSb QCLs are much less than those in AlInAs/GaInAs QCLs, (2) narrower ridges lead to significantly cooler active regions of InAs/AlSb QCLs due to poor heat transport in the cross-plane direction (across interfaces) and that most of the heat flows out of the active region in the lateral direction, and (3) the cavity length of the laser has little influence on the self-heating effect of the device, but the long cavity reduces mirror loss and threshold current density.