Highly sensitive multicore fiber accelerometer for low frequency vibration sensing

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

doi:10.1038/s41598-020-73178-x

Josu Amorebieta, Joel Villatoro + Show 7 more

Open Access

https://doi.org/10.1038/s41598-020-73178-x

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Abstract

We report on a compact, highly sensitive all-fiber accelerometer suitable for low frequency and low amplitude vibration sensing. The sensing elements in the device are two short segments of strongly coupled asymmetric multicore fiber (MCF) fusion spliced at 180° with respect to each other. Such segments of MCF are sandwiched between standard single mode fibers. The reflection spectrum of the device exhibits a narrow spectrum whose height and position in wavelength changes when it is subjected to vibrations. The interrogation of the accelerometer was carried out by a spectrometer and a photodetector to measure simultaneously wavelength shift and light power variations. The device was subjected to a wide range of vibration frequencies, from 1 mHz to 30 Hz, and accelerations from 0.76 mg to 29.64 mg, and performed linearly, with a sensitivity of 2.213 nW/mg. Therefore, we believe the accelerometer reported here may represent an alternative to existing electronic and optical accelerometers, especially for low frequency and amplitude vibrations, thanks to its compactness, simplicity, cost-effectiveness, implementation easiness and high sensitivity.

Highlights

Those based on interferometry and fiber Bragg gratings (FBGs) are the most advanced configurations
Optical fiber interferometric accelerometers feature larger dynamic range, wider frequency response band and higher sensitivity compared to some electronic a ccelerometers[16,17,18]
When the physical device is subjected to the same effect, a slight wavelength shift is likely to happen as well apart from the amplitude variation. This is caused by two factors: in first place, the impossibility to apply the bending only and exactly at the fusion splice point; and in second place, the length difference of 0.8 mm between the multicore fibers (MCFs) segments, which will cause a small variation in the shift of each against the same stimulus

Summary

Introduction

Those based on interferometry and fiber Bragg gratings (FBGs) are the most advanced configurations. This effect, added to the asymmetrical arrangement of the cores and their orientation, will cause detectable wavelength shift and coupled power variations that will have unique characteristics depending on the applied bending direction and amplitude, making the MCF ideal for direction-sensitive bending sensors.

Results

Conclusion