A Novel Miniature Fiber-Optic Magnetic Field Sensor Based on Ampere Force and Dual-Polarization Fiber Laser

A dual-polarization fiber grating laser is proposed to sense a magnetic field by attaching the fiber laser to a copper wire. When an electrical current is injected into the copper wire and a perpendicular magnetic field is applied, the current generates Ampere force to squeeze the fiber laser and change the birefringence inside the laser cavity, resulting in beat note frequency change. The magnetic field induced beat note frequency change can be discriminated from environment disturbances by applying an alternating current, which therefore demonstrates a novel miniature fiber-optic magnetic field sensor with high sensitivity and inherent immunity to disturbances