2025/07/18 by C. J. Mitchell, Longqi Zhou, Mitchell, Colin J. +21
Chemistry · Engineering · Physics and Astronomy · #Advanced Fiber Laser Technologies #Applied Physics (physics.app-ph) #FOS: Electrical engineering #FOS: Physical sciences #Optics (physics.optics) #Semiconductor Lasers and Optical Devices #Signal Processing (eess.SP) #Spectroscopy and Laser Applications #electronic engineering #information engineering
paper · pdf · doi:10.48550/arxiv.2507.14003
openalex publication_date 2025/07/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present a novel scheme for hybrid integration of quantum cascade laser bars with germanium-on-silicon waveguides operating in the mid-infrared. The laser bars are flip-chip bonded onto a germanium-on-silicon target chip without active alignment, acheiving end-fire coupling efficiency of up to 45% (3.5 dB loss) in pulsed operation. Optical power estimates indicate 20-30 mW coupled into the waveguides. The passive alignment approach, combined with a CMOS-compatible photonic integrated circuit fabrication process, offers a scalable pathway to fully integrated mid-infrared photonic systems for sensing, free-space communications, and the realisation of novel light sources.