Novel fibres for next-generation fibre-optic gyroscopes

Abstract

The fibre-optic gyroscope (FOG) is one of the most successful optical fibre sensors in history and it has become a keystone technology for high-performance rotation sensing. Its core sensing element is a long optical fibre wound into a coil. Here, sensitivity to rotation scales in proportion with optical path length, and thus much FOG development has been directed toward deploying longer fibres within the same footprint. However, the fibre itself can be a major source of signal errors via Rayleigh backscattering, polarization cross-coupling, environmental effects, and non-linearity – thus, high-performance FOGs require advanced strategies to suppress these limitations in their multi-kilometer long sensing coils. This work explores two exciting fibre technologies which show great potential to address these challenges. The first is multicore optical fibre (MCF), in which multiple, independent optical waveguides (cores) are placed within the same glass cladding. These densely packed cores increase optical length, and thus gyro sensitivity, while preserving the coil geometry. This work details the construction of a fully functional interferometric FOG employing state-of-the-art MCF. This demonstrator uses a 7-core, 154 m long fibre coil, and through acquisition of detailed performance data, we realize the 7X sensitivity improvement conferred by use of MCF. The promise of MCF for FOGs is further highlighted by illustrating novel designs and improvements to existing FOG systems which are afforded by this signal density enhancement. The second fibre technology is hollow core antiresonant fibre (ARF), in which a glass microstructure confines signal light to the central hollow region of the fibre. Ultra-low interaction between light and glass renders the fibre orders of magnitude less sensitive to material and environmental effects. This work highlights several benefits of ARFs for FOGs, including the first-ever measurements of polarization coupling in long, symmetric ARFs. These data show that polarization in ARFs can be 2-3 orders of magnitude purer than the theoretical limit for solid fibres. It is further shown, through use of an advanced resonator FOG testbed, that ARFs are immune to many of the material-related guidance impairments which beleaguer solid core FOGs. Through the analysis and demonstrations presented here we show the great promise that these two novel fibres can offer future FOGs. This is a boon for existing and emerging FOG applications which require high-performance navigation in a compact format – from new concepts in robotics and autonomous vehicles which are beginning to shape our world, to the next-generation of space and submarine applications which will explore new worlds.

More information

Identifiers

ORCID for Austin Acker Taranta: orcid.org/0000-0002-5666-6800

ORCID for Austin Taranta: orcid.org/0000-0002-5666-6800

ORCID for Jayanta Sahu: orcid.org/0000-0003-3560-6152

Catalogue record

Export record