FBG magnetic field sensor based on V-hinge structure

Magnetic field measurement plays an important role in many fields such as resource exploration, national defense security, and disaster monitoring. In order to solve the problem of low sensitivity of the current optical fiber magnetic field sensor, a Fiber Bragg Grating (FBG) magnetic field sensor based on V-hinge structure was proposed. The V-shaped hinge structure integrates the design of symmetrical thin plates and a driving plate into the FBG magnetic field sensor. This design allows for the amplification of the microstrain of the Terfenol-D rod, thereby enhancing the sensitivity of the sensor. Firstly, the sensor model was established and the theoretical analysis was carried out. Secondly, the sensor model was imported into COMSOL for simulation analysis of the sensor. Finally, the actual sensor was developed and tested in the zero magnetic space. The experimental results show that when the bias magnetic field is 35mT, the highest sensitivity of the sensor reaches 164.46 pm/mT, the magnetic field resolution is 6.08 µT, and the sensor directivity basically conforms to the cosine-squared law. The research results provide reference for the development of high-sensitivity fiber optic magnetic field sensors.