Two-Dimensional Magnetic Field Vector Sensor Based on Tilted Fiber Bragg Grating and Magnetic Fluid

A two-dimensional (2D) magnetic field vector sensor is proposed and experimentally demonstrated. A theoretical model is established to analyze the physical mechanism in detail. The transmission response of the sensor depends on the angle (θ) between the magnetic orientation and the polarization direction of tilted fiber Bragg grating (TFBG) and the intensity of magnetic field (H) when keeping θ constant and exhibits a sinuous behavior when keeping H constant. When -θ_c <; θ <; θ_c and π - θ_c <; θ <; π + θ_c, the transmission increases with the increment of H, while it decreases when θ_c <; θ <; π - θ_c or π + θ_c <; θ <; 2π - θ_c. The resonance peak in the transmission spectrum does not shift with the change of H within the experimental error. The experimental results are in good agreement with our theoretical analysis. 2D magnetic field vector sensor could be achieved by employing rotators to change the orientation of the sensor head. Our proposed TFBG-based sensing system would find potential applications in magnetic field vector sensing and refractive index sensing for polarized liquids.