The resonant micro-optic gyroscope (RMOG) represents a significant advancement in the miniaturization and integration of high-precision gyroscopes. In RMOGs, the optical waveguide ring resonator constitutes the core component. The resonance-enhanced Sagnac effect provides the theoretical foundation for the miniaturization of resonant optical gyroscopes. The advent of integrated optics and micromachining technologies enables the successful fabrication of various low-loss and high-finesse resonant cavities. However, in addition to backscattering and polarization noise, the optical Kerr effect emerges as a significant source of noise that limits the accuracy of RMOGs. In this study, a method for reducing optical Kerr noise in RMOGs is proposed, and the simulation results are validated using experimental data.

This paper presents a comparative and analytical examination of the optical Kerr effect-induced error coefficients in reflective and transmissive waveguide ring resonators (WRRs). The effects of modulation parameters on optical Kerr effect-induced errors are investigated, and the optical Kerr error coefficient in RMOGs is reduced by optimizing the modulation coefficient. Subsequently, an RMOG system comprising a transmissive silica WRR with a diameter of 5.96 cm and a finesse of 118 is constructed, which serves as the rotation-rate sensing element. The optical Kerr error coefficient and its relationship with the modulation parameters are tested. Subsequently, an RMOG system with an optical-power feedback loop is constructed to improve the stability of the optical power input to the WRR.

The optical Kerr error coefficient is calculated to be 4.7[(°)/h]/μW . After analysis and testing, the optical Kerr error coefficient and its relationship with the modulation parameters are shown to be consistent with theoretical expectations. Following the optimization of the modulation frequencies of the clockwise and counterclockwise beams at 2.6 MHz and 2.7 MHz, respectively, the optical Kerr error coefficient reduces to 1.5[(°)/h]/μW . Finally, an RMOG system with an optical-power feedback loop is constructed to improve the stability of the light intensity incident on the WRR. The measured results show that the optical-power fluctuation reduces from 1.42% prior to the implementation of the power feedback loop to 1.86×10^-5 following its implementation. This reduction in the optical-power fluctuation corresponds to a reduction in the peak-to-peak fluctuation of the gyroscope output caused by the optical Kerr effect from 52.6(°)/h to 0.015(°)/h in the RMOG. The minimum corresponding bias stability is 0.0015(°)/h. The aforementioned results show that the optical Kerr effect in the RMOG is effectively suppressed.

This study shows that a transmissive WRR in an undercoupled state can exhibit a low optical Kerr error coefficient. Additionally, the Kerr error coefficient can be further reduced by optimizing the modulation parameters of the system. Finally, using an optical-power feedback technique based on second-harmonic demodulation can significantly enhance the stability of the optical power input to the WRR. The aforementioned measures allow for the effective suppression of optical Kerr effect-induced errors in RMOGs.