2025/06/04 by Russell, Ryan L., Moritz Merklein, Choon Kong Lai +12
Engineering · Physics and Astronomy · #Advanced Fiber Optic Sensors #FOS: Physical sciences #Mechanical and Optical Resonators #Optics (physics.optics) #Photonic and Optical Devices
paper · pdf · doi:10.48550/arxiv.2506.03575
openalex publication_date 2025/06/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Chip-scale coherent light sources are required in applications spanning metrology and sensing to telecommunications. Brillouin lasers (BLs) offer a route to ultra-coherent optical sources in compact microresonators with free spectral range (FSR) matched to the Brillouin frequency shift (BFS). However, BFS - FSR matching typically facilitates cascaded Brillouin scattering, constraining achievable BL output power and coherence. Here, we demonstrate inhibition of cascading in a planar-integrated chalcogenide microresonator by exploiting the photonic bandgap (PBG) associated with a post-fabrication inscribed, reconfigurable intracavity Bragg grating. The PBG inhibits energy transfer within the target Brillouin scattering pathway, such as from pump to first-order Stokes wave. As a quantitative measure of Brillouin scattering inhibition, we report at least six-fold increase in threshold for onset of BL oscillation, which is ultimately limited by thermorefraction. For on-chip pump power of 399 mW, sufficient for a tenth-order Brillouin cascade, complete inhibition was achieved. Our work positions Bragg grating microresonators as an enabling platform for high performance on-chip BL sources, with reconfigurable modes of operation.