Theoretical analysis on SPR based optical fiber refractive index sensor with resonance wavelength covering communication C+L band

Surface plasmon resonance (SPR) based optical fiber refractive index sensor with oxide film, such as magnesium oxide (MgO), tellurium dioxide (TeO2) or titanium dioxide (TiO2) on Au is theoretically analyzed. Simulation results show that sensitivity is increased and resonance wavelength is tunable to longer wavelength simultaneously by increasing the thickness of oxide. For different oxides with same thickness, SPR sensor coated with oxide with highest refractive index (Au-TiO2) shows the highest sensitivity. By changing the thickness of different oxides, sensors can work in communication band with high sensitivity. When the thicknesses of MgO, TeO2 and TiO2 are set at 80 nm, 45 nm and 40 nm respectively, the sensitivity are all larger than 9000 nm/RIU, meanwhile the resonance wavelength covers communication C + L band(1530 nm–1625 nm).