Li Zongyang, Liu Kui, Liu Jing, Lu Zehuang, Zhang Jie
Opt Express. 2021 Mar 29;29(7):9737-9748. doi: 10.1364/OE.415916.
Large-scale passive resonant gyroscopes (PRGs) have been utilized in the measurement of Earth rotation. We report on a scheme of phase-sensitive heterodyne detection in large-scale PRGs. By injecting three separated beams into different longitudinal modes of the ring cavity and self-demodulating the detected signals, the backscattering disturbance and the cavity length fluctuation effect both can be isolated. With the implementation of this new scheme, we can obtain the Earth rotation signal with a Sagnac frequency that is twice of that of the traditional scheme, which enhance the equivalent scale factor of the laser gyroscopes. On the other hand, the quantum noise limit of the instrument can also be further suppressed due to the improvement of the signal-to-noise ratio. With this new scheme, the theoretical rotational sensitivity of a 3 m × 3 m large scale PRG can be as low as 10 rad/s/Hz. With this rotational sensitivity, the measurement of the length of day or the test of the general relativity can be realized.
大型无源谐振陀螺仪（PRG）已被用于地球自转测量。我们报告了一种大型PRG中的相敏外差检测方案。通过将三束分离的光束注入环形腔的不同纵向模式并对检测信号进行自解调，可以隔离后向散射干扰和腔长波动效应。通过实施这种新方案，我们可以获得具有萨尼亚克频率的地球自转信号，该频率是传统方案的两倍，这提高了激光陀螺仪的等效比例因子。另一方面，由于信噪比的提高，仪器的量子噪声极限也可以进一步降低。采用这种新方案，一个3米×3米的大型PRG的理论旋转灵敏度可低至10弧度/秒/赫兹。凭借这种旋转灵敏度，可以实现日长测量或广义相对论测试。
