Research on fiber-optic magnetic field sensor based on surface plasmon resonance

Abstract This paper proposes a fiber optic magnetic field sensor based on the surface plasmon resonance effect. By filling the elliptical magnetic fluid medium layer in the optical fiber cladding, the structure increases the effective contact area between the magnetic medium and the fiber core, thereby improving the sensing performance, at the same time, the structural stability of the sensor is considered. Coating the metal silver film on the inner surface of the elliptical cavity can prevent the metal layer from being oxidized. In addition, compared with other metal materials, silver film can significantly improve the resolution of the output spectrum. The performance of the sensor was studied using the finite element method. The results show that the sensor can measure the commonly used low magnetic field in the range of 50Oe-115Oe, it also has the advantages of strong sensitivity about S=2.02 nm/Oe, high resolution R=4.9×10-3Oe and large Figure of Merit FOM=0.024/Oe. Based on the characteristics of miniaturization, integration and high sensitivity, the sensor can be considered for the applications in military, medical, industrial production and other fields.