Advancement and expectations on mode-locked laser gyroscopes

Laser gyroscopes afford extremely precise measurement of ultraslow angular velocity and play an irrefutable role in engineering seismology, tidal detection, aviation, aerospace, satellite navigation, and other inertial systems. With recent progress of mode-locked fiber lasers, particularly the realization of effective bidirectional generation, their applications in the fields of gyroscopic sensing have attracted tremendous attention. Besides the merits of excellent structure compactness, maintenance-free operation, and rather low cost, remarkably, the mode-locked laser gyroscope presents a promising approach for eliminating the lock-in effect caused by the synchronization of counterpropagating resonant frequencies, which is the most severe sensing limitation of traditional laser gyroscopes. In this paper, recent advancements and perspectives in this research are reviewed. The fundamentals of gyroscopic sensing employing mode-locked pulse lasers are presented. Architectures of novel mode-locked laser gyroscopes inspired by ultrafast optics, including bright-soliton mode-locked laser gyroscopes and dark-soliton mode-locked laser gyroscopes, are described in detail. Bottlenecks and deficiencies of the exhibited mode-locked laser gyroscopes owning to inherent physical mechanisms or measurement methods currently used are further analyzed. Finally, feasible methods of improving the performance of mode-locked laser gyroscopes are broadly expounded upon to build a bridge between their scientific development research and practical applications. (C) 2022 Optica Publishing Group