Vector magnetic field sensing characteristics of magnetic fluid coated side-polished eccentric-core fiber structure

The article proposes a novel all fiber vector magnetic field sensor structure based on magnetic fluid (MF) and side-polished eccentric-core fiber structure. The basic connection structure of the sensor head consists of an eccentric-core fiber (ECF) fused in the middle of two single-mode fibers (SMFs). The eccentric-core fiber (ECF) was side-polished to destroy the circular symmetry of the fiber. We encapsulated magnetic fluid (MF) on the surface of optical fiber structure by using capillary and combine the anisotropic distribution characteristics of MF to achieve vector magnetic field sensing. The research results indicate that the fiber structure shows a magnetic field intensity sensitivity of -0.381 dB/mT within 44~62 mT, with a maximum direction sensitivity of 519 pm/°. The sensor proposed in this paper adopts all-fiber structure, which is simple to manufacture and small in size, and has potential application prospects in many fields.