Surface plasmon resonance sensor based on exposed-core microstructured optical fibres

A surface plasmon resonance (SPR) sensor based on exposed-core microstructured optical fibres (EC-MOFs) is presented and numerically characterised. The exposed section (analyte channel) of the EC-MOF is coated with a SPR supporting thin film of gold. The asymmetrically coated fibre can support two separate resonance peaks, with orthogonal polarisations (x- and y-polarised peaks). Although the sensitivity of both the polarised peaks is very similar, the narrower linewidth of the y-polarised peak provides a much enhanced signal-to-noise ratio. The SPR sensing performance for a large refractive index (RI) range from 1.33 to 1.42 is evaluated. The sensor has higher sensitivity for detecting the high analyte RI. The feasibility of using EC-MOFs to develop a fast-response, real-time and distributed SPR sensor is determined.