Hollow-core anti-resonant fiber magnetic field sensor based on negative curvature Semi-Tubular

Abstract

Magnetic field detection is critical for geological exploration in complex environments. Based on the principle of leaky mode resonance (LMR), a semi-tubular hollow-core anti-resonant fiber (HC-ARF) filled with a magnetic fluid (MF) is proposed for magnetic field sensing in this study. When the semi-tubular air cladding cavity is filled with MF, a Fabry–Perot (F-P) resonator can be formed between the MF and the silica cladding, and the negative-curvature semi-tubular structure can confine the light in the fiber core. Different magnetic field strengths vary the reflectivity and resonance conditions of the F-P resonator, which in turn affect the resonance wavelength and transmittance. The results show that the sensitivity of the wavelength shift can reach 68.39 pm/Oe for magnetic field strengths in the range of 60–180 Oe. This HC-ARF magnetic field sensor can realize magnetic field detection under light sources of different wavelengths according to the selection of the resonance order. The sensor exhibits a low loss, wide bandwidth, and high sensitivity, and thus it has good development prospects for geological exploration.