Magnetic field sensor based on magnetofluid and FBG

The utility model relates to a magnetic field sensor based on a magnetofluid and a FBG. The magnetic field sensor is made by a principle that changes of a magnetic fluid refractive index result in changes of optical grating reflection wavelength. The magnetic field sensor comprises a broadband light source, a FBG demodulation instrument, a three-terminal circulator, a magnetofluid solution, a capillary, and a residual cladding FBG. The broadband light source inputs light to the residual cladding FBG through the circulator. When refractive index of the magnetofluid solution around the FBG changes with an external magnetic field, reflection wavelength of the FBG changes with the external magnetic field. Finally magnetic field information is demodulated through the FBG demodulation instrument. The residual cladding FBG is immersed in the magnetofluid solution, and is packaged by the capillary. The magnetic field sensor is simple in manufacturing and low in cost.