一种新型的基于磁性液体的光纤Sagnac磁场传感器  

A Novel Fiber Sagnac Magnetic Field Sensor Based on Magnetic Fluid

作　　者：祖鹏[1,2] 向望华[1,2] 白扬博[1,2] 金永兴 

机构地区：[1]天津大学精密仪器与光电子工程学院,天津300072 [2]光电信息技术科学教育部重点实验室,天津300072 [3]School of Chemical and Biomedical Engineering,Nanyang Technological University,Singapore,637598

出　　处：《光学学报》2011年第8期49-53,共5页Acta Optica Sinica

摘　　要：提出一种使用磁性液体的新型光纤Sagnac磁场传感器。磁性液体具有磁致可变双折射效应和二向色性,在外加磁场作用下,液体中的磁性纳米粒子沿磁场方向结链规则排列,形成各向异性。将其制成液体薄膜,放入具有一段保偏光纤的Sagnac环中,使光纤Saganc干涉仪的正弦形状干涉光谱可随外磁场变化。光纤中传输光垂直经过磁性液体薄膜,在外加磁场与磁性液体薄膜平面平行时,传输光产生双折射现象,干涉光谱的峰值波长随着外加磁场的变化而变化。传感器灵敏度与磁性液体薄膜厚度有关,对于60μm的磁性液体薄膜,灵敏度为16.7pm/Oe(1Oe≈79.578A/m),分辨率为0.60Oe。而在外加磁场与磁性液体平面垂直时,干涉光谱的峰值波长几乎不随外加磁场的变化而变化。An optical fiber Sagnac magnetic field sensor based on magnetic fluid is proposed. The magnetic fluid exhibits magneto-optic birefringence under external magnetic field, in which the nanoparticles form chains along the magnetic field and cause the anisotropy. The interference spectrum of the sensor shifts with the external magnetic field due to the magnetic fluid film inserted in the Sagnac loop together with a section of polarization maintaining fiber. The output spectrum shifts with the variation of magnetic field strength when the plane of the magnetic fluid is perpendicular to the direction of the light and parallel to the direction of the external magnetic field. The achieved sensitivity and resolution of the sensor, which are related to the thickness of the magnetic film, are 16.7 pm/Oe （1 Oe≈79.578 A/m） and 0.60 Oe for 60 μm thickness, respectively. When the plane of the magnetic fluid is perpendicular to the direction of the magnetic field, the output spectrum does not shift with the variation of the magnetic field strength.

关 键 词：光纤光学 光纤磁场传感器 SAGNAC干涉仪 磁性液体 磁光效应 双折射 

分 类 号：O436[机械工程—光学工程]