Magnetic fluid-infiltrated anti-resonant reflecting optical waveguide for magnetic field sensing based on leaky modes

A magnetic fluid (MF)-infiltrated antiresonant reflecting optical waveguide has been fabricated for the magnetic field sensing based on resonant leaky modes. In a hollow core photonic crystal fiber, the MF is selectively infiltrated into one hollow hole in the air cladding. A Fabry-Perot resonator can be formed between the MF and the silica cladding. Both the resonant condition and the reflectivity of the Fabry-Perot resonator are changed under different magnetic field, which can be measured through the wavelength shift and transmission power at the dip wavelength. The sensitivities of up to 109 pm/Oe and 0.064 dB/Oe are achieved for methods of wavelength shift and transmission power at the dip wavelength. The antiresonant reflecting optical waveguides are widely used for the accurate measurement of magnetic field in the fields of transportation, medicine, smart grids, and so on.