Polarization-Switching FBG Interrogator for Distributed Point Measurement of Magnetic Field Strength and Temperature

We report on the design and implementation of a novel optical fiber system for dual point measurement of magnetic field strength and temperature. The system incorporates a polarization switching technique that enables ratiometric processing of the orthogonal circularly polarized reflections from low-birefringence fiber Bragg gratings. High-resolution magneto-optical measurement of either static or dynamic magnetic fields may be achieved while retaining the capability for serial multiplexing and temperature measurement. The system provides a practical solution to intrinsic fiber point measurement of magnetic field, leading to potential applications in adverse environmental conditions, where electronic or extrinsic optical technologies are unsuitable.