为了实现对电气设备直流磁场的高灵敏度检测，针对现有传统磁场传感器存在的抗电磁干扰能力差、尺寸大、结构复杂等问题，提出了一种基于双锥微纳光纤的磁场传感器。仿真计算了双锥微纳光纤中的光场能量分布，分析了双模场模式干涉传感原理和磁流体特性。通过电极放电加热拉锥法制备了双锥微纳光纤，填充磁流体制备了磁场传感器。建立了磁场检测实验平台，通过实验验证了传感器对磁场的响应及传感器的重复性。结果表明，该传感器在0 ~ 10 mT的磁感应强度范围内具有线性响应，线性度为0.998，磁场传感灵敏度为-173.96 pm/mT，误差小于± 0.3 mT，重复性良好，可见该传感器满足输变电设备mT级磁场检测要求。

To achieve high-sensitivity detection of direct current (DC) magnetic fields in electrical equipment and overcome the limitations of conventional magnetic field sensors, such as poor electromagnetic interference resistance, large size, and complex structure, a magnetic field sensor based on dual-tapered fiber was proposed. The optical field energy distribution within the dual-tapered fiber was simulated, and the principles of dual-mode interference sensing and magnetic fluid characteristics were analyzed. The dual-tapered fiber was fabricated using an electrode discharge heating tapering method, and the magnetic field sensor was developed by filling it with magnetic fluid. A magnetic field detection experimental platform was established, and the sensor's response to magnetic fields as well as its repeatability were experimentally validated. The results demonstrate that the sensor exhibits a linear response within a magnetic flux density range from 0 mT to 10 mT, with a linearity of 0.998, magnetic field sensitivity of -173.96 pm/mT, an error within± 0.3 mT, exhibiting excellent repeatability. The sensor is shown to meet the mT-level magnetic field detection requirements for power transmission and transformation equipment.