Fiber-Optic Vector Magnetometer Based on Magnetic Fluid and Fiber Bragg Grating Written on a Multi-Clad Fiber

The magnetic fluid is used to integrate with a special fiber Bragg grating (FBG) inscribed over the core and innermost cladding of a multi-clad fiber, which acts as a bridge between magnetic field measurement and FBG. The FBG is etched by hydrofluoric acid and packaged with a magnetic fluid inside a capillary. The reflection of the sensor provides two resonance modes of which the cladding mode intensity shows a great response to both the magnetic field intensity and the direction. Meanwhile, the fundamental core mode intensity is quiet stable, and thus the proposed sensor clearly demonstrates the potential to simultaneous measurement of magnetic field and temperature.