Vector magnetic field sensor based on orthogonal off-set spliced optical fiber cladded with magnetic fluid

Based on the anisotropic distribution of magnetic nanoparticles within magnetic fluid under an external magnetic field, a novel, to the best of our knowledge, vector magnetic field sensor based on an orthogonal offset spliced optical fiber structure cascaded with fiber taper has been proposed. The expression of interference dip wavelength with respect to external magnetic field is formulated, and the dual-parameter sensing matrix is established. Simultaneous measurement of magnetic field intensity and direction is realized. The corresponding physical principle is clarified. The sensing properties are experimentally investigated and theoretically verified. The theoretical results are in good agreement with the experimental ones.