Gyroscopes are inertial sensors whose field of application is rapidly expanding. The growing interest in autonomous systems, CubeSats as well as their constellations, and unmanned vehicles is stimulating a strong interest in miniaturized gyroscopes for integration in inertial units with a volume smaller than 100 cm3. Some of these applications require gyroscopes that are highly immune to disturbances, especially vibrations, mechanical shocks, and radiation. In these application contexts, the use of microelectromechanical gyroscopes is often avoided in favor of sensors without moving parts, such as optical gyroscopes based on the Sagnac effect. The technology of interferometric optical gyroscopes is currently considered to be potentially capable of enabling the development of highly innovative angular velocity sensors, which are simultaneously inertial grade and miniaturized. This paper critically examines the scientific and R&D activity aimed at miniaturization of interferometric optical gyroscopes, focusing on recent results, perspectives, and physical limitations. Interferometric optical gyroscopes with dimensions similar to those of microelectromechanical gyroscopes and better performance than the latter in terms of immunity to disturbances have not yet been demonstrated, but this paper shows how this goal could be realistically achieved in the medium term through the use of integrated microphotonics. This paper compares the technology being analyzed with the competitive technologies, highlighting their strengths and limitations.
