Angle-resolved hollow-core fiber-based curvature sensor

TL;DR

This paper introduces a novel hollow-core fiber-based sensor capable of simultaneously measuring the magnitude and direction of bending, using spectral shifts caused by curvature-induced mode field changes.

Contribution

It presents a new multi-axis curvature sensor design utilizing a tubular-lattice fiber with varied tube thicknesses and a calibration routine for accurate measurement.

Findings

Curvature radii and angles are determined with less than 7% error.

The sensor effectively detects both bending magnitude and direction.

The approach offers a promising method for advanced curvature sensing applications.

Abstract

We propose and theoretically study a new hollow-core fiber-based curvature sensor with the capability of detecting both bending magnitude and angle (direction). The new sensor relies on a tubular-lattice fiber that encompasses, in its microstructure, tubes with three different thicknesses. By adequately choosing the placement of the tubes within the fiber cross-section, and by exploring the spectral shifts of the fiber transmitted spectrum due to the curvature-induced mode field distributions' displacements, we demonstrate a multi-axis bending sensor. In the proposed sensor, curvature radii and angles are retrieved via a suitable calibration routine, which is based on conveniently adjusting empirical functions to the sensor response. Evaluation of the sensor performance for selected cases allowed to determine the curvature radii and angles with percentual errors of less than 7%. The approach proposed herein provides a promising path for the accomplishment of new curvature sensors able to resolve both the curvature magnitude and angle.