Optimization of Strain-Balanced Heterostructures for High Power 4-5 Micron Quantum Cascade Lasers

In order to extract the full potential of quantum cascade laser technology, a heterostructure with a large conduction band offset is required in order to minimize thermal leakage associated with high average power operating conditions. Strain-balanced heterostructures, based on GaInAs/ AlInAs/ InP, exist which are predicted to allow efficient laser operation in the 3-5 micron wavelength region. Due to a large mismatch relative to InP, strict control over layer composition and thickness is required in order to accurately reproduce ideal quantum well heterostructures. In this project, the main effort will be to optimize quantum well shape using strain-balanced heterostructures. In addition, experimental data will be gathered in order to update band structure parameters, which will allow for more accurate laser design. By the end of the project, a laser source with >20 mW continuous wave power in the 3-5 micron wavelength will be demonstrated.