Abstract: A full-polarization Faraday magnetic field sensor based on a Sagnac interference system and a modulation method are provided. The full-polarization Faraday magnetic field sensor includes a light source, an optical fiber coupler, a polarizer, a polarization beam splitter, a polarization controller, a magnetic field sensing unit, a detector and a polarization maintaining optical fiber. An optical signal is emitted by the light source, passes through the optical fiber coupler and the polarizer in sequence, and is divided into a clockwise path and an anticlockwise path by the polarization beam splitter. Angles between fast axis directions of the two polarization maintaining optical fiber loops and a polarization direction of the polarizer are respectively clockwise 45° and anticlockwise 45°. The two polarization maintaining optical fiber loops has opposite winding directions, a same diameter, and a same number of winding turns.

Abstract: A full-polarization Faraday magnetic field sensor based on a Sagnac interference system and a modulation method are provided. The full-polarization Faraday magnetic field sensor includes a light source, an optical fiber coupler, a polarizer, a polarization beam splitter, a polarization controller, a magnetic field sensing unit, a detector and a polarization maintaining optical fiber. An optical signal is emitted by the light source, passes through the optical fiber coupler and the polarizer in sequence, and is divided into a clockwise path and an anticlockwise path by the polarization beam splitter. Angles between fast axis directions of the two polarization maintaining optical fiber loops and a polarization direction of the polarizer are respectively clockwise 45° and anticlockwise 45°. The two polarization maintaining optical fiber loops has opposite winding directions, a same diameter, and a same number of winding turns.