High sensitivity vector magnetic field sensor based on magnetic fluid encapsulated SMF–MMF–TCF–SMF structure

Abstract A vector magnetic field sensor based on magnetic fluid encapsulated sandwich-like optical fiber structure, i.e. a segment of single-mode fiber (SMF)-multimode fiber-three core fiber-SMF, is proposed. The magnetic field sensing characteristics of the designed sensing structure have been demonstrated in this work. Owing to the non-circular symmetry of the fiber structure and the enhanced higher-modes excitation, the sensing structure exhibits high magnetic field sensitivity. In our experiment, the maximum intensity sensitivity of −1710 pm mT −1 and the maximum direction sensitivity of −810 pm/ ∘ are obtained respectively, in the range of 30–41 mT. The proposed magnetic field sensor features a simple structure and high sensitivity, demonstrating significant potential for applications in precision electromagnetic measurement.