Application of Fiber Optic Surface Plasmon Resonance Sensor for Measuring Liquid Refractive Index

An optical fiber sensor based on surface plasmon resonance (SPR) phenomenon that can be used for liquid refractive index testing is presented in this article. The effect of various parameters like the refractive index of the core and the liquid type on the shape of the SPR spectrum is analyzed, utilizing relative spectrum measurement technology. The relationship curves between several kinds of liquids with the same refractive index with their resonance wavelengths are also obtained using the sensing probe. Furthermore, experimental results of liquids with high refractive index reveal that the improved probe with SiO film has the ability to extend the detection upper limit of refractive index and keep the toughness of optical fiber at the same time.