High-Temperature Operation of a Quantum Cascade Laser With Definite Parity of the Wave Functions

We propose an active region structure for a mid-infrared quantum cascade laser (QCL) where each wave function in the lower (upper) laser sub-band has a definite even (odd)-parity to increase the optical dipole matrix element $\langle \text {z}\rangle $ . The enhanced $\langle \text {z}\rangle $ leads to improving the optical gain of the QCL. We have demonstrated a $\lambda {\sim 7.5~\mu \text {m}}$ Fabry–Perot GaInAs/AlInAs QCL with a high-reflection coated rear-facet operating continuously up to a temperature of 378 K.