Magnetic field sensor based on magnetic fluid clad etched fiber Bragg grating

A novel fiber optical fiber-magnetic sensor based on magnetic fluid is proposed in this paper. The stable nanoparticles Fe3O4 magnetic fluid was synthesized firstly; the Fe3O4 magnetic fluid was injected in capillaries containing etched fiber Bragg grating (FBG) as sensing element. The reflected Bragg wavelength was changed by varying the magnetic field which is perpendicular to the axial of FBG. Experimental results show that the FBG with small diameter has more sensitive wavelength shift in magnetic field. When the magnetic field increases to 25 mT, the wavelength shift of the most sensitive FBG is 86 pm, and the etched FBG shows reversible response on magnetic fields under 16 mT.