Reducing Noise in a Ring-laser Gyro Based on Stimulated Brillouin Scattering

Abstract

Although Brillouin scattering is a parasitic effect in many systems, stimulated Brillouin scattering (SBS) can also be harnessed for useful applications. Brillouin lasers have been of interest in the fields of optics and photonics since the early 1990s because of the extremely narrow linewidths they offer [1]. Chip-scale versions of these devices have begun to emerge more recently, and the performance attained in them is steadily approaching that of their fiber counterparts [2-4]. Honeywell is using Brillouin lasing in chip-scale SiO2/Si3N4 waveguide resonators to create a robust ring-laser gyroscope. Current limitations on gyro noise are 1) limited optical power in the sensing light, due to cascading of Brillouin lasing to higher SBS orders, and 2) scattering and absorption loss of the Brillouin light in the resonator. We are addressing both issues.