Quantum Cascade Laser Integration on Photonic Integrated Circuits for Compact Mid-Infrared Sensing

Heterogeneous integration of QCLs on photonic integrated circuits (PICs) allow for the combination of multiple wavelengths and functionalities on a single chip, reducing the size, cost, and power consumption of traditional mid-IR sensing systems [1], [2]. However, direct flip-chip assembly of QCLs on PICs turns out to be less efficient with low optical power due to the requirement of critical vertical alignment of QCLs and PICs [3]. As an alternative, this work presents a hybrid-assembled QCLs on PICs via an intermediate Si submount, which was measured with a high output power of 19 mW in continues wave (CW) mode and 25 mW in pulse wave (PW) mode. Furthermore, simulations were conducted for efficiently coupling QCLs with the Ge waveguide. This work especially paves the way for compact mid-infared spectroscopy devices.