Magnetic field and temperature dual-parameter sensor based on magnetic fluid materials filled photonic crystal fiber

A dual-parameter sensor based on a photonic crystal fiber (PCF) concatenated with a fiber Bragg grating (FBG) is proposed and experimentally demonstrated for simultaneous measurement of magnetic field and temperature. Novel magnetic fluids (MF) with different concentration and surfactant are filled in the air holes of PCF. The magnetic field measurement property is only determined by PCF, while the temperature is co-determined by PCF and FBG. Experimental results show that the wavelength shift has a good linearity corresponding with temperature and magnetic field. Temperature and magnetic field sensitivity are proportional to concentration of MF and are affected by different surfactants. For PCF point, when polyethylene glycol is used as a surfactant and the magnetic fluid concentration is equal to 0.15, the highest magnetic field sensitivity is up to 924.63 pm/mT. The proposed sensor has a high sensitivity as well as cross-sensitivity resistance, which provides a promising candidate for dual-channel filtering or multi-parameter measurement applications.