The F0G98A single axis fiber optic gyroscope is a fully solid-state high-precision digital closed-loop high-precision single axis fiber optic gyroscope that integrates optics, mechanics, and electronics. Adopting self-developed high-performance photonic crystal polarization maintaining fiber ring, low-temperature resistant coating, and precise fiber untwisting process, not only minimizes the impact of temperature changes and geomagnetism on the performance of the gyroscope, but also significantly improves key indicators of the fiber optic gyroscope, such as bias stability, angle random walk, proportionality factor linearity, and stability.