Optical fiber interference magnetic field sensor based on Terfenol-D magnetostrictive material

Abstract

It is suggested and designed to use Terfenol-D magnetostrictive material in a fiber extrinsic F-P interferometric magnetic field sensor. The two reflective end faces of the F-P cavity are, respectively, the copper reflective layer and the fiber end face. As a result, changes of the magnetic field have an impact on the F-P cavity's cavity length, and the environmental magnetic field can be detected by measuring the variation in cavity length. The typical relationship between magnetic field and spectral drift of the sensor is theoretically analyzed. The sensitivity is measured experimentally to be 0.82 nm/mT for a magnetic field intensity of 0 mT to 70 mT at room temperature. The sensor has a compact structure, and the complexity of the low-level interference signal demodulation makes it suitable for use in engineering.