High Sensitivity Magnetic Field Sensor Composed of Magnetostrictive Material Terfenol-D and Fabry-Perot Interferometer

A highly sensitive magnetic field sensor was proposed using magnetostrictive material Terfenol-D and Fabry-Perot interferometer (FPI) and experimental verification was conducted. Ordinary single-mode fiber are fusion spliced together with quartz capillary, and then a layer of PVA film is coated on the end face of the capillary to form an FPI. Then, the FPI structure is glued onto the end face of the Terfenol-D rod using UV adhesive to form a magnetic field sensor. When the external magnetic field changes, the Terfenol-D rod will stretch and contract, causing a change in the F-P cavity length of the FPI pasted together, resulting in a shift in the resonant wavelength of the FPI spectrum. By demodulating the wavelength shift, the magnetic field size can be obtained. The magnetic field sensitivity of the sensor obtained in the experiment reached -0.5172 nm/mT, with a fitting degree of 0.9959. In addition, magnetic field sensors have good stability and repeatability, and respond quickly.