Thermal-induced phase-shift error of a fiber-optic gyroscope due to fiber tail length asymmetry.

As a high-precision angular sensor, the fiber-optic gyroscope (FOG) usually shows high sensitivity to disturbances of the environmental temperature. Research on thermal-induced error of the FOG is meaningful to improve its robust performance and reliability in practical applications. In this paper, thermal-induced nonreciprocal phase-shift error of the FOG due to asymmetric fiber tail length is discussed in detail, based on temperature diffusion theory. Theoretical analysis shows that the increase of thermal-induced nonreciprocal phase shift of the FOG is proportional to the asymmetric tail length. Moreover, experiments with temperature ranging from -40°C to 60°C are performed to confirm the analysis. The analysis and experiment results indicate that we may compensate the asymmetry of fiber coil due to imperfect winding and the assembly process by adjusting the fiber tail length, which can reduce the thermal-induced phase-shift error and further improve the adaptability of the FOG in a changing ambient temperature.