Sensing Structure Based on Surface Plasmon Resonance in Chemically Etched Single Mode Optical Fibres


Many optical systems based on surface plasmon resonance (SPR) have been developed for working as refractometers, chemical sensors or even for measuring the thickness of metal and dielectric thin films. Sensors based on SPR present very high sensitivity to refractive index (RI) variations when compared to the traditional RI sensors. However, these kinds of systems are usually large, expensive and therefore cannot be used for remote sensing. Optical fibre sensors based on SPR are usually implemented using multimode optical fibres cope with the requirements for remote sensing. In this section a new type of SPR sensor based in a single mode fibre (SMF) is proposed. A section of the SMF was chemically etched by emersion in a 48 % hydrofluoric acid solution, resulting in a tapering effect, with the cladding removing while the core is kept intact. Simulation results are in good agreement with the experimental spectral resonance dip attained around 1550 nm. Sensitivities of 3800 and 5100 nm/RIU were achieved for the reflection and for the transmission modes, respectively, for RI in the 1.33 to 1.37 range.



subject category

Chemistry; Science & Technology - Other Topics; Materials Science


Coelho, L; de Almeida, JMMM; Santos, JL; Ferreira, RAS; Andre, PS; Viegas, D

our authors


This research was performed in the framework of project PTDC/FIS/119027/2010 (Plasmonics Based Fibre Optic Sensing with Enhanced Performance). FCOMP-01-0124-FEDER-037271-Ref. FCT PEst-C/CTM/LA0011/2013 and PEST-OE/EEI/LA0008/2013 are also acknowledged. L. Coelho would like to acknowledge FCT for providing the PhD Scholarship SFRH/BD/78149/2011.

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