A novel magnetic fluid based magnetic field F-P current sensor

Abstract

A novel current measuring method based on the magnetic controllable refractive index characteristic of magnetic fluid and fiber optic Fabry-Perot (F-P) interferometer is proposed and demonstrated. A current sensing probe composed of fiber optic F-P interferometer filled with magnetic fluid (MF) is analyzed theoretically and numerically. Based on the theoretical analysis and numerical simulation results, the structure of the fiber optic F-P current sensor is designed and fabricated experimentally. The relationship of the magnetic fluid at various magnetic field is measured experimentally and the numerical model of relationship between the refractive index of magnetic fluid and the characteristics of F-P current sensor is built up. The sensor has the advantages of simple structure, low cost, and high magnetic field measurement sensitivity. A high magnetic field measurement sensitivity of 0.034 nm/Gs is achieved with the magnetic field varied from 0 to 391.5Gs, and the experiment results are consistent with the theoretical analysis and numerical simulation.