An Interferometric Fiber-Optic Gyroscope With Low Self-Noise for Rotational Seismology Based on a Dual-Channel Configuration

In this work, we present the development of a high-performance interferometric fiber optic gyroscope specifically designed for rotational seismology. The system exhibits enhanced sensitivity and holds promise for precision sensing applications. A single broadband light source drives two Sagnac interferometers, each of which operates as a sensing channel. By employing reverse-phase modulation and a compensation scheme, the system effectively suppresses relative intensity noise. In addition, high-order eigenfrequency modulation is incorporated to mitigate the influence of thermal phase noise. The proposed configuration is implemented using two polarization-maintaining fiber coils, each 6.7 km in length and about 0.35 m in diameter. Experimental evaluations demonstrate strong noise correlation between channels and verify the significant improvements in sensitivity. The developed system achieves a self-noise level of 1.5 × 10−9rad/s/ √ Hz, which is 12 times lower than that of the single-channel system. The angular random walk and bias instability are measured at 3.8 × 10−6deg/ √ h and 3.7 × 10−5deg/h, respectively. This outstanding performance not only confirms the effectiveness of the proposed dual-channel strategy in mitigating intrinsic noise, but also validates the system’s suitability for high-precision geophysical applications.