# A Giant Magneto-Strictive Material-Based Fabry–Perot Interferometer-Type 3D Vector Magnetic Field Sensor

## TL;DR

This paper introduces a 3D magnetic field sensor using three orthogonal interferometers bonded to a magneto-strictive material for high sensitivity and direction detection.

## Contribution

A novel 3D vector magnetic field sensor using orthogonal Fabry–Perot interferometers and a GMM block for enhanced sensitivity.

## Key findings

- The sensor achieved sensitivities of 245.13, 159.06, and 168.59 pm/mT on different planes.
- CO2 laser modulation improved the sensitivity of the interferometers.
- The sensor can determine both the magnitude and direction of magnetic fields simultaneously.

## Abstract

This paper presents the design and experimental validation of a highly sensitive vector magnetic field sensor based on three mutually orthogonal Fabry–Perot interferometers (FPIs). The orthogonally arranged FPIs are bonded to a giant magneto-strictive material (GMM) block. Under an applied magnetic field, the magneto-strictively induced strain in the GMM block is transferred to the FPIs. Meanwhile, the FPIs, composed of single-mode fiber (SMF)–hollow-core fiber (HCF)–SMF, are further modulated by CO2 laser, by which the higher sensitivities are obtained. The highest sensitivities of FPIs achieved 245.13, 159.06, and 168.59 pm/mT on the X-Y, X-Z, and Y-Z planes, respectively. By demodulating the distinct wavelength drifts of the three orthogonal FPIs, both the magnitude and direction of the magnetic field can be simultaneously determined.