Novel spectral fiber optic sensor based on surface plasmon resonance

A novel fiber optic surface plasmon resonance (SPR) sensing device based on spectral interrogation of SPR in a miniature fiber optic sensing element using depolarized light is reported. Optimization analysis of the sensor based on the equivalent planar waveguide approach and the mode expansion and propagation method is presented. A laboratory prototype of the sensor has been proved to be able to measure refractive index variations as small as 5×10−7. Suitability of the sensor for biosensing has been demonstrated by detecting IgG via respective monoclonal antibodies immobilized on the SPR sensor surface.