High-performance vector bending and orientation distinguishing curvature sensor based on asymmetric coupled multi-core fibre

Oskar Arrizabalaga,Gilberto Brambilla,Qi Sun,Joseba Zubia,Rodrigo Amezcua-Correa,Jose Enrique Antonio-Lopez,Martynas Beresna,Axel Schülzgen,Joel Villatoro,Idurre Sáez De Ocáriz,Timothy Lee,Javier Velasco Pascual

doi:10.1038/s41598-020-70999-8

Abstract

Fibre optic technology is rapidly evolving, driven mainly by telecommunication and sensing applications. Excellent reliability of the manufacturing processes and low cost have drawn ever increasing attention to fibre-based sensors, e.g. for studying mechanical response/limitations of aerospace composite structures. Here, a vector bending and orientation distinguishing curvature sensor, based on asymmetric coupled multi-core fibre, is proposed and experimentally demonstrated. By optimising the mode coupling effect of a seven core multi-core fibre, we have achieved a sensitivity of − 1.4 nm/° as a vector bending sensor and − 17.5 nm/m−1 as a curvature sensor. These are the highest sensitivities reported so far, to the best of our knowledge. In addition, our sensor offers several advantages such as repeatability of fabrication, wide operating range and small size and weight which benefit its sensing applications.

Highlights

Fibre optic technology is rapidly evolving, driven mainly by telecommunication and sensing applications
Our proposed sensor is based on a strongly-coupled multi core fibre (MCF) fabricated at the University of Central Florida (Orlando, USA) by the well-established stack and draw method
The multi-core fibres (MCF) consists of a symmetrical structure formed with a central core surrounded by another six cores made of silica doped with germanium and embedded in pure silica cladding

Summary

Introduction

Fibre optic technology is rapidly evolving, driven mainly by telecommunication and sensing applications. By optimising the mode coupling effect of a seven core multi-core fibre, we have achieved a sensitivity of − 1.4 nm/° as a vector bending sensor and − 17.5 nm/m−1 as a curvature sensor These are the highest sensitivities reported so far, to the best of our knowledge. Fibre reinforced polymers are composites used in almost every type of advanced engineering structures, with their usage ranging from aircraft, helicopters and spacecraft through to boats, ships and civil infrastructure such as bridges and buildings. Some of the benefits of this type of sensor include accuracy, a wide variety of sizes and shapes, and a simple operating principle Their performance is affected by humidity, temperature and hysteresis, repeatability and accuracy fall with prolonged use, and they can be damaged by statics or current overloads. Light propagating in the fibre changes its parameters such as spectral composition, intensity, polarization, which can be analysed and quantified by means of an optical spectrum analyser (OSA) or power meter

Methods

Results

Conclusion