Magnetic field sensor based on phase-shifted fiber Bragg grating with magnetic fluid

Abstract

A magnetic field sensor based on a novel phase-shifted fiber Bragg grating with magnetic fluid is proposed and experimentally demonstrated. It is fabricated by cleaving a uniform fiber Bragg grating at the center point, introducing a micrometre gap as a phase-shift and then filling the gap with magnetic fluid. External applied magnetic field changes refractive index of the magnetic fluid, leading to a wavelength shift of the phase-shifted induced transmission peak. By detecting transmission peak wavelength shift with magnetic field intensity, optical measurement of magnetic field is realized. Experimental results show a linear response of wavelength shift to magnetic field intensity with a high sensitivity of 2.4 pm/Oe in the testing magnetic field intensity range from 0 to 120 Oe.