Compact omnidirectional multicore fiber-based vector bending sensor

Josu Amorebieta,Joseba Zubia,Enrique Antonio-Lopez,Gaizka Durana,Angel Ortega-Gomez,Joel Villatoro,Axel Schülzgen,Rodrigo Amezcua-Correa,Rubén Fernández

doi:10.1038/s41598-021-85507-9

Josu Amorebieta, Joseba Zubia + Show 7 more

Open Access

https://doi.org/10.1038/s41598-021-85507-9

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Abstract

We propose and demonstrate a compact and simple vector bending sensor capable of distinguishing any direction and amplitude with high accuracy. The sensor consists of a short segment of asymmetric multicore fiber (MCF) fusion spliced to a standard single mode fiber. The reflection spectrum of such a structure shifts and shrinks in specific manners depending on the direction in which the MCF is bent. By monitoring simultaneously wavelength shift and light power variations, the amplitude and bend direction of the MCF can be unmistakably measured in any orientation, from 0° to 360°. The bending sensor proposed here is highly sensitive even for small bending angles (below 1°).

Highlights

We propose and demonstrate a compact and simple vector bending sensor capable of distinguishing any direction and amplitude with high accuracy
The demand for sensors that are capable of monitoring in real-time parameters such as amplitude and direction of bending and/or curvature has remained consistent for years due to their relevance in fields such as structural health monitoring (SHM)
As the cores are arranged asymmetrically, each of them suffers different levels of stress against the same bending plane and radius, causing the refractive index of each to vary independently. Such situation affects directly to the propagating supermodes, which modifies the output spectrum of the normalized coupled power in Eq (1). This is what makes asymmetric multicore fiber (MCF) good candidates for direction-sensitive bending sensors, as the variation of the normalized coupled power will be specific for each bending case, giving rise to detectable changes in the spectrum of an single mode fiber (SMF)–MCF structure in terms of wavelength shift and/or light power variation depending on the applied bending direction

Summary

Introduction

We propose and demonstrate a compact and simple vector bending sensor capable of distinguishing any direction and amplitude with high accuracy. They are only capable of measuring the amplitude of the bending in certain directions by analyzing the wavelength shift or the intensity variation in the spectrum.

Results

Conclusion