Chip-integrated Brillouin Saser Gyroscope

On-chip Brillouin laser gyroscopes harnessing opto-acoustic interaction are an emerging approach to detect rotation, due to their small footprint, excellent stability and low power consumption. However, previous implementations rely solely on optical readout, leaving the simultaneously generated saser (sound amplification by stimulated emission) undetected due to the lack of capability to access the acoustic output. Here, we propose a gyroscope based on saser detection using a suspension-free chip platform that supports low-loss confinement of both optical and acoustic modes. With experimental feasible parameter with optical and acoustic quality factors of 10^5 and 5000, respectively, sasers show significantly suppressed thermal and frequency noises, leading to gyroscope performance that outperforms its optical counterparts. We predict an angle random walk ~0.1 deg/sqrt(h) by saser gyroscope, while a conventional Brillouin laser gyroscope requires significantly higher pump power and optical quality factor to achieve comparable performance. Our work establishes the foundation for active phononic integrated circuits with Brillouin gain, opening avenues in inertial sensing, quantum transduction, and RF signal processing.