A novel magnetic field sensor based on the combination use of microfiber knot resonator and magnetic fluid

In this paper, a novel all-fiber magnetic field sensor based on a device consisting of microfiber knot resonator (MKR) and magnetic fluid (MF) is proposed for the first time. MF is infused into a homemade sealed cell containing a partially embedded MKR in low-index polymer as sensing element. Experimental results show that the resonance wavelength of the proposed sensor regularly varies with changes of the applied magnetic field. When the magnetic field increases to 22mT, the wavelength shift reaches nearly 200pm.