The fiber-optic sensor comprises a ring-shaped fiber structure that is coated with magnetic fluid. The Higher Educational Key Laboratory for Flexible Manufacturing Equipment Integration of Fujian Province, Xiamen Institute of Technology, Xiamen 361021, China The State Key Laboratory for Mechanical Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710054, China Shandong. 2D-Vector Magnetic Sensing Based on Ring-Shaped Fiber-Optic Structure Coated with Magnetic Fluid Citation:Lin, Q. Micromachines2023, 14. The high-resolution measurement of magnetic field is of great significance in scientific research and production.