Ultra-small interferometric fiber optic gyroscope with an integrated optical chip

Abstract

This study proposes a novel interferometric fiber optic gyroscope (IFOG) based on an integrated optical chip, applicationspecific integrated circuit, and small-diameter sensing coil. The overall size and weight of the prototype are 30 mm × 30 mm × 30 mm and 68 g, respectively, making it the smallest closed-loop IFOG, to the best of our knowledge. A static experiment shows that the bias stability of the integrated IFOG is very close to the theoretical accuracy limit determined by the fiber coil and can satisfy the requirements of near-navigation-grade compact inertial navigation systems.

Miniaturization of Interferometric Optical Gyroscopes: A Review

“…For the state-of-the-art, the minimum dimensions of the fiber coils specifically intended for FOG application (quadrupole or octupole winding pattern) are an internal diameter of 10 ∼ 15 mm and an external diameter < 30 mm [37]. Further R&D activities aimed at reducing the size of the coils made of standard PM fibers are currently ongoing, but a reduction in coil size inevitably implies a PER degradation that may not be compliant with the achievement of navigation grade.…”

“…The reduction of the external diameter of the fiber coil inevitably needs the reduction of the external diameter of the fiber, and, generally speaking, less coating means less immunity to external stress and, potentially, higher polarization cross-coupling in the fiber. Fiber coils made of PM fiber with a coating diameter of 100 µm are on the market [38] and were utilized in miniaturized FOG prototypes [37], but a detailed characterization of these PM fibers is not available in the literature. At the state-of-the-art level, we do not have experimental evidence that these fibers and these coils with diameters < 30 mm can support navigation-grade performance.…”

“…At the state-of-the-art level, we do not have experimental evidence that these fibers and these coils with diameters < 30 mm can support navigation-grade performance. Data in [37] only show that intermediate grade is achievable. A navigation grade FOG integrating a coil with diameter = 40 mm and made of a standard PM fiber is on the market [39].…”

A Novel Closed-Loop Control to Solve Light Source Power Fluctuations in the Fiber-Optic Gyroscope

“…In 2019, KVH Co. integrated a polarizer and two Y waveguides into a single chip, its IFOGs achieving a bias stability of 0.048 °/h [ 11 ]. In 2022, Shang et al produced an IFOG with a size of only 3 cm × 3 cm × 3 cm [ 12 ].…”