Vector Magnetic Field Sensor Based on Magneto-Sensitive Functionalized Three-Core Fiber Structure

We have proposed and experimentally demonstrated a vector magnetic field sensor based on a magneto-sensitive functionalized three-core fiber (TCF) structure. The fiber-optic magnetic field sensor adopts a sandwich-like magnetofluid encapsulated single-mode fiber (SMF)-TCF-SMF structure. Owing to the noncircular symmetric structure, thereby enabling the fiber sensing structure exhibits response to environmental magnetic field strength and direction. The experimental results shows that the maximum strength sensitivity and direction sensitivity are −1.23 nm/mT and 0.73 nm/°, respectively, within the range of 35–44 mT when the TCF length is 10 mm. The proposed magnetic field sensor offers several advantages, including simple structure, ease of fabrication, and high sensitivity.