Temperature-compensated magnetic field sensor based on surface plasmon resonance and directional resonance coupling in a D-shaped photonic crystal fiber

Abstract A D-shaped and magnetic fluids (MF) infiltrated photonic crystal fiber (PCF) based Surface Plasmon Resonance (SPR) sensor is proposed for magnetic field sensing. By inserting a defective cavity filled with toluene solution in the cladding layer, the temperature-compensated mechanism can be achieved based on the dependence of the MF refractive index (RI) on temperature and magnetic field. By the combined use of SPR and directional resonance coupling in the designed PCF, a dual-parameter matrix method is utilized to solve the temperature-induced problem. The relationship between resonant wavelength and external magnetic-field can be derived with a high sensitivity 0.87nm / mT. As the Au-Ag composite film is coating on the plane surface of the photonic crystal fiber, the proposed sensor has the advantage of simplification and easy fabrication.