| In the past 20 years, mid-infrared Quantum Cascade Lasers (mid-IR QCLs) have been experiencing rapid development and have become practical mid-IR sources for a variety of applications. There is particular technological interest in high efficiency lasers designed for the midwave infrared (MWIR) atmospheric window (3-5 µm) and longwave infrared (LWIR) atmospheric window (8-13 µm). This work presents a systematic study over mid-IR QCLs, including theoractical modeling, device fabrication and characterization. An effective bandstructure calculation method is implemented in this work for active region modeling. A standard process for fabricating mid-IR QCLs has been developed, based on which both LWIR (∼9 µm) and MWIR (∼4 µm) QCLs have been successfully demonstrated. Comprehensive testing results are analyzed and discussed, yielding valuable information about the current device design. |
