Tactical-Grade Three-Axis Interferometric Fiber-Optic Gyroscope With a Silica Integrated Optical Chip

As an important component in inertial navigation system (INS), the fiber-optic gyroscope (FOG) is developing toward integration and miniaturization. In this article, an integrated photonic chip comprised of a light source, three photodiodes, and four 3-dB couplers for three-axis FOG based on silica waveguide is proposed. The interferometric FOG (IFOG) assembly process is simplified, the cost is reduced, and production efficiency is improved. The overall size of the three-axis IFOG is reduced significantly to only $50\times 50\times 30$ mm, and a bias stability is better than 0.5°/h for a sensing coil with a diameter of 26 mm and can satisfy the requirements of tactical-grade compact INSs. To the best of our knowledge, this is the first reported to date for the three-axis silica integrated optical chip-based IFOG.