Microresonator Brillouin Laser Gyroscope

Citation

Lai, Yu-Hung (2019) Microresonator Brillouin Laser Gyroscope. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/10XE-G776. https://resolver.caltech.edu/CaltechTHESIS:05282019-120721714

Abstract

Optical Gyroscopes are among the most accurate rotation-measuring devices and are widely used for navigation and accurate compasses. With the advent of integrated photonics for complex telecommunication chips, there has been interest in the possibility of chip-scale optical gyroscopes. Besides the potential benefits of miniaturization, such solid-state systems would be robust and resistant to shock. In this thesis, we investigate a chip-based optical gyroscope using counter-propagating Brillouin lasers on a monolithic silicon chip. The near-degenerate lasers mimic a commercial ring laser gyroscope including the existence of a locking band. By using physical properties associated with the Brillouin process, a solid-state unlocking method is demonstrated. We focus on three topics to explore the potential of the counter-propagating Brillouin-laser gyroscope. First, we explore the physics of the counter-propagating Brillouin lasers by deriving the theory to link the passive cavity mode with the lasing gain medium. We explicitly show how the dispersion, Kerr nonlinearity, dissipative coupling, and Sagnac sensing affect the beating frequency of the Brillouin lasers. Second, we experimentally demonstrate the performance of the gyroscope. Most notably, the gyroscope is used to measure the rotation of the Earth, representing an important milestone for chip-scale optical gyroscopes. Third, we investigate the non-Hermitian interaction between the counter-propagating Brillouin lasers. We test the recent prediction of the EP-enhanced Sagnac effect, and observe a Sagnac scale factor boost by over 4X by measurement of rotations applied to the resonator. Our research shows the feasibility of the chip-based Brillouin laser gyroscope. This gyroscope paves the way towards an all-optical inertial guidance system.

Thesis Files