An optical fiber-based vector magnetic field sensor combining fiber Bragg gratings (FBGs) and magnetic fluids (MFs) is proposed and experimentally demonstrated. The Bragg gratings are inscribed on the core and the cladding of a multi-clad fiber (MCF). Splicing the MCF with a standard single-mode fiber (SMF) via core mismatch provides a cladding-mode generation mechanism. Then, the high-order cladding mode is excited with the increasing off-axis distance. There are two kinds of resonant modes in the reflection spectrum of the sensor, which are the high-order cladding mode and the fundamental core mode. The intensity of the first mode shows an excellent response to the magnetic field intensity and the direction. The intensity sensitivity of the magnetic field sensor is −0.143 dB/Oe in a linear range of 60–110 Oe. Furthermore, the second mode intensity is quite stable and varies with the ambient temperature. Thus, the proposed magnetic field sensor can simultaneously measure the magnetic field and the temperature.

提出并实验证明了一种结合光纤布拉格光栅 (FBG) 和磁流体 (MF) 的基于光纤的矢量磁场传感器。布拉格光栅刻在多包层光纤 (MCF) 的纤芯和包层上。通过纤芯不匹配将 MCF 与标准单模光纤 (SMF) 熔接在一起，提供了一种包层模式生成机制。然后，随着离轴距离的增加，高阶包层模式被激发。传感器的反射光谱中存在两种谐振模式，即高阶包层模式和基本纤芯模式。第一模式的强度对磁场强度和方向显示出极好的响应。磁场传感器的强度灵敏度为 -0.143 dB/Oe，线性范围为 60-110 Oe。此外，第二模式强度相当稳定，并随环境温度变化。因此，所提出的磁场传感器可以同时测量磁场和温度。