为提高光纤传感器磁场检测中的敏感度,进一步实现弱磁场环境中的高精度场强勘测,提出一种基于磁流包覆与冷却拉锥透射式全光纤高灵敏磁场传感器,拉锥过程采用间歇式停顿冷却技术,可更加便捷获得高质量干涉谱,减缓光子晶体光纤空气孔塌缩,制作工艺简单,具有可操纵性强、灵敏度高、损耗小等优势,实现了高灵敏磁场环境实时在线检测,并对传感器的变温影响进行了讨论。实验结果表明,光子晶体光纤的拉锥长度为5.5 mm、腰椎直径为75 μm时,可得到良好的干涉光谱,在0~78 Oe(1 Oe =^79.578 A·m -1)磁场范围内,灵敏度达95 pm/Oe,线性拟合度为98.31%。

This paper proposes an all-optical-fiber high-precision magnetic field sensor based on magnetic fluid coating and cooling tapering to improve the sensitivity of optical fiber sensors in magnetic field detection and realizes high-precision real-time monitoring of field intensity under a weak magnetic field. The intermittent cooling method in the tapering process enhances the quality of the interference spectrum conveniently and slows the air-hole collapse of the photonic crystal fiber. Because of its simple manufacturing process, strong maneuverability, high sensitivity, and low degree of loss, the sensor realizes real-time online detection in a high-sensitivity magnetic field. Finally, the influence of the temperature variation of the sensor is discussed. Experimental results show that the photonic crystal fiber obtains a good interference spectrum at a tapering length of 5.5 mm and waist diameter of 75 μm. The sensor exhibits a highly linear response to external magnetic fields ranging from 0 to 78 Oe (1 Oe =^79.578 A·m ^-1) with a sensitivity of 95 pm·Oe ^-1. The degree of linear fitting is approximately 98.31%.