Excessively tilted fiber grating-based vector magnetometer.

A compact optic-fiber vector magnetometer is proposed and experimentally demonstrated, which is based on an excessively tilted fiber grating (Ex-TFG) assistant with the magnetic fluid (MF). Without any complicated processing, the cladding mode resonances of the bare Ex-TFG packaged by the MF show high sensitivity to slight perturbations by the magnetic field. Due to the excellent magneto-optical properties of the MF and the azimuth-dependent refractive index sensitivity of the Ex-TFG, such a magnetometer can achieve the magnetic field intensity sensitivity of 2.45 nm/mT and the orientation sensitivity of 0.41 nm/deg. In addition, based on the spectral interrogation, the detection limit of the magnetic field intensity could reach around 8.1 µT at the minimum wavelength measurement accuracy of 0.02 nm.