Experimental realization and numerical simulation of wavelength-modulated fibre optic sensor based on surface plasmon resonance

This work presents the manufacturing process of miniaturized SPR sensors using optical fibres. Silver is deposited as a thin layer around the unclad core of a multimode optical fibre. Fibre optic sensors (FOS) are obtained in this way, which have been studied by the modulation of white light. Silver FOS response has been characterized versus different parameters such as the refractive index of the surrounding medium and the film thickness. The response curve of FOS over a significant range of refractive indices shows the known minima shift due to the SPR. Numerical simulation demonstrates that the SPR theoretical curves agree well with experiment. The comparison between numerical and experimental results also allows for the optimization of the physical parameters for the metal film. In order to increase the sensor sensitivity we study the theoretical response of grafting a selective organic transducing biolayer.