Fiber resonator using negative-curvature anti-resonant fiber with temperature stability

The coupling efficiency of hollow-core fiber changes with temperature, which leads to the decrease of the finesse (F) of fiber resonator and limits the performance of the resonant fiber optic gyroscope (R-FOG) system. Negative-curvature anti-resonant fiber (ARF) can maintain single-mode characteristics under the condition of large mode field diameter, achieve efficient and stable fiber coupling, and significantly improve the consistency of the F of the spatial coupling resonator in variable temperature environment. A new type of ARF with a mode field diameter (MFD) of 25 μm is used to fabricate a fiber resonator with a length of 5.14 m. In the range of 25 °C-75 °C, the average F is 31.45. The ARF resonator is used to construct an R-FOG system that shows long-term bias stability (3600 s) of 3.1 °/h at room temperature, 4.6 °/h at 75°C. To our knowledge, this is the best reported index of hollow-core fiber resonator and R-FOG system within the temperature variation range of 50°C test.