1.6 μm Lasing and Mid-Wave Infrared Detection in InP-Based Transistor-Injected Quantum Cascade Structures

Coherent, mid-wave infrared sources are garnering attention for a variety of applications such as spectroscopy, remote chemical sensing, and free-space optical communication. The transistor-injected quantum cascade laser (TI-QCL) is a proposed device that combines the active-region of a standard quantum cascade laser with a heterojunction bipolar transistor. By placing the cascaded superlattice within the field region of the base-collector junction, the dependence of output wavelength and optical power can be separated. This is expected to unlock broader use cases in a single device by expanding tunability and introducing additional modulation schemes. In this work, a new InP-based TI-QCL design is presented, devices fabricated, and those devices optically characterized. Improvements in the epitaxial structure and fabrication process have produced devices that emit spontaneous near infrared light (NIR) at around 1.6 μm and mid-wave infrared light above 6 μm. In addition, NIR lasing has been demonstrated, satisfying one of the two output modes proposed by the TI-QCL design. Both results are important steps in the goal of developing a fully functional laser.