FBG Magnetic Field Sensor Based on Magnetostrictive Displacement Amplification

Magnetic field measurement is crucial in various fields, such as biomedicine, electromechanical devices, rotational speed measurement, and positioning technology. However, the sensitivity of current fiber Bragg grating (FBG) magnetostrictive material-based magnetic field sensors is constrained by the magnetostrictive coefficient of the magnetostrictive material itself. This study investigates a highly sensitive FBG magnetic field sensor that employs Terfenol-D material to detect magnetic fields. Magnetostrictive deformation of Terfenol-D is amplified through a displacement amplification mechanism and subsequently applied to the FBG, thus achieving high-sensitivity magnetic field measurements. Experimental tests demonstrate that the sensor structure provides approximately 3.6 times amplification for both static and alternating magnetic fields. Therefore, the FBG magnetic field sensor can reach high-sensitivity measurements of both static and alternating magnetic fields.