We present a study of noise suppression by fusion in fiber-optic gyroscopes based on the source-sharing architecture. A theoretical model is proposed for the detailed analysis of noise mechanism. The importance of the modulation parameters is revealed, and the optimal modulation strategies are given. Through simulations and experiments, we demonstrate that the proposed fusion scheme not only suppresses self-noise including relative intensity noise and thermal phase noise, but also achieves complete elimination of environmental disturbances. Up to 5.8-fold suppression of self-noise and 5.2-fold reduction of bias instability is obtained in the experimental apparatus when compared with the performance before fusion. In the applications of fiber-optic gyroscopes for precision measurement, the proposed schemes effectively suppress the noises at the system level.

We report a design for gravity gradient measurements based on Sagnac interferometry. An structure with two masses is designed to convert the effect of gravity gradients into rotational motion. Sagnac interferometry based on optical fibers is introduced to probe its rotational motion. The systematic effects are analyzed theoretically and validated by the static observation of a experimental apparatus. In a 37-day record, we achieve a noise level of 5 × 10 ^-12 rad s ^-2 Hz ^-1/2 under a room-temperature environment without any vibration isolation and magnetic shielding devices. The corresponding contribution for the gravity gradient measurement is estimated to 1 × 10 ^-2 E Hz ^-1/2 .

The relative intensity noise (RIN) of the light source is an important noise affecting the performance of portable interferometric fiber optic gyroscopes (IFOGs). In this work, two commonly used RIN suppression methods of IFOG, i.e., time-domain delay structure, and dual-polarization structure, are experimentally compared under the same conditions. On this basis, a composite structure of IFOG is proposed. The experimental results show that the proposed IFOG achieves a better Rin suppression effect, which achieves a sensitivity improvement of up to 6.09 times to 2.3 × 10 ^-8 rad/s/√Hz in an enclosed area of 68 m ² . It has a flat frequency response over a bandwidth of 0.05-100 Hz. The angular random walk and bias instability are improved by 8.65 times and 8.06 times, respectively. These studies provide theoretical and technical support for the development of high-performance IFOG and facilitate its application in more fields.

In the field of precision measurements, highly sensitive interferometric fiber-optic gyroscopes (IFOGs) hold significant value. However, the application of IFOGs is constrained by intrinsic noise and environmental disturbances. This study conducts a comprehensive noise analysis based on the conventional phase generated carrier (PGC) algorithm. On the basis of noise theory, an improved fusion algorithm is proposed in conjunction with a light source sharing configuration to suppress the primary intrinsic noise–relative intensity noise (RIN) and reduce environmental disturbances. Experiments under excitation by piezoelectric transducers (PZTs) and environmental disturbances are carried out to verify the effectiveness of the scheme. In comparison to the minimum configuration using the conventional PGC algorithm, the new scheme achieves a 16.5-fold suppression in self-noise, 16.0-fold suppression in angular random walk, and 10.0-fold suppression in bias instability. More importantly, the ability to suppress environmental disturbances is demonstrated. The proposed scheme demonstrates the superior ability to make high-precision measurements in complex environments, showcasing world-leading performance and offering insights into the application of IFOGs in a broader range of measurement scenarios.

The degradation in the accuracy of interferometric fiber optic gyroscopes (IFOGs) in complex environments has become a significant limiting factor for their practical applications. In this paper, we introduce a novel IFOG configuration based on polarization multiplexing and dual optic-fiber coils. The new configuration leverages two orthogonal polarization states within the fiber, achieving double the length of the fiber coil. This not only achieves the enhancement the IFOG’s sensitivity but also effectively compensate for and suppress errors arising from variations in the magnetic field and temperature in the external environment. We analyzed the principle of suppression of magnetic and Shupe errors by this configuration and conduct corresponding experiments. The experimental results show that the proposed configuration achieves a remarkable 90-fold reduction in magnetic error and a 24-fold reduction in Shupe error following compensation. Moreover, owing to the strong correlation between two orthogonal polarization states, the relative intensity noise (RIN) in the proposed configuration is effectively suppressed, resulting in a 4-fold reduction of the self-noise. The new configuration’s sensitivity can reach 4.2 × 10 ^-8 rad/s/√Hz, the root power spectrum density (PSD) is almost flat from 0.03 Hz to 100 Hz. This configuration provides a new option for constructing IFOGs with superior performance and robust environmental adaptability.

This paper presents the development of a high-performance three-component fiber optic rotation seismometer (FORS) named DC-Rot3C for rotational seismic observation. Its core sensing element is a novel dual-channel interferometric fiber optic gyroscope (IFOG), which differs from conventional minimum configuration. The IFOG in DC-Rot3C is composed of two sensing channels, which can effectively suppress self noise such as relative intensity noise. This paper provides a detailed demonstration and analysis of the optical configuration, demodulation technology, layout construction, and noise suppression mechanisms of the developed DC-Rot3C. Furthermore, the performance of DC-Rot3C is tested, and the experimental results show that, with an effective sensing area of only $246\,\,\mathrm{m^{2}}$ , the self-noise remains flat from 0.001 Hz to 100 Hz, reaching a sensitivity of $6.2\times 10^{-9}\;\mathrm{rad/s/\sqrt{Hz}}$ . Additionally, the angle random walk (ARW) reaches $4.54\times 10^{-9}\;\mathrm{rad/\sqrt{s}}$ , and the bias instability (BI) reaches $2.96\times 10^{-10}\;\mathrm{rad/s}$ . Compared with other IFOGs and FORSs, the DC-Rot3C exhibits superior performance with the same sensing area, providing a high-precision tool for seismic observation.