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 func-tion in the lower (upper) laser sub-band has a definite even(odd)-parity to increase the optical dipole matrix element 〈z〉.The enhanced 〈z〉 leads to improving the optical gain of theQCL.We have demonstrated a λ~7.5μm Fabry-Pérot GaInAs/AlInAs QCL with a high-reflection coated rear-facet-operating continuously up to a temperature of 378 K.