Relative Intensity Noise Suppression Methods for Interferometric Fiber-Optic Gyroscopes

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
$2.3\times 10^{-{8}}$
rad/s/
$\sqrt {\text {Hz}}$
in an enclosed area of 68
$\text{m}^{{2}}$
. It has a flat frequency response over a bandwidth of 0.05–100 Hz. The angular random walk (ARW) and the bias instability (BI) are improved by 8.65 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.