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 50–115 Oe, it also has the advantages of strong sensitivity about S = 2.02 nm/Oe, high resolution R = 4.9 × 10⁻³ Oe 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.

本文提出了一种基于表面等离子体共振效应的光纤磁场传感器。该结构通过在光纤包层中填充椭圆形磁流体介质层，增加了磁介质与纤芯的有效接触面积，从而提高了传感性能，同时兼顾了传感器的结构稳定性。在椭圆腔内表面镀上金属银膜可以防止金属层被氧化。此外，与其他金属材料相比，银膜可以显着提高输出光谱的分辨率。使用有限元方法研究了传感器的性能。结果表明，该传感器可以测量50-115 Oe范围内的常用低磁场， = 2.02 nm/Oe，高分辨率 R  = 4.9 × 10 ^-3 Oe 和大品质因数 FOM  = 0.024/Oe。基于小型化、集成化和高灵敏度的特点，该传感器可考虑用于军事、医疗、工业生产等领域。