Direct optical path measurement in fibre-optic gyroscopes: A potential method for compensating slow-drifting errors

Abstract

This research explores innovative methods for compensating slow drift and measurement errors in fibre-optic gyroscope (FOG) systems, caused by environmental factors, particularly temperature variations. The study focuses on directly measuring the optical path length in FOG systems to mitigate these errors. Three architectures are proposed for implementing optical path measurement: using an optical coupler with an additional pulse laser, employing a micro-electro-mechanical systems (MEMS) optical switch with a pulse laser, and utilizing additional multifunction integrated optics chip (MIOC) control. All solutions utilize the time-of-flight (ToF) principle to measure changes in optical path length. The research demonstrates the feasibility of real-time optical path length measurement in FOG systems without significantly disrupting their operation. This approach shows promise for improving the accuracy of FOG-based sensors in applications such as inertial navigation systems, civil engineering, and rotational seismography, where environmental factors can lead to accumulating errors over time. The findings provide a foundation for further research and development in navigation and sensing applications, with the MIOC-based solution considered most promising due to its minimal required changes to existing FOG systems.