Investigation Of The Fiber-Optic Sensors Based On Surface Plasmon Resonance

We convert Kretschmann structure on tapered fiber-optic to excite the SPR effect and demonstrate an ultra-high sensitive tapered fiber-optic sensor.And we convert the Otto structure on SMF to excite the SPR effect,which is the best highlight,and present a fiber-optic nano-displacement senor and a “T” structure refractive index sensor.The simulation results as below shown:An ultra-high sensitive tapered fiber-optic sensor based SPR is presented.The result shows that the electric field intensity is reinforced when SPR is excited.The resonant wavelength shifts towards the shorter wavelength with the refractive index increasing.When varying the refractive index from 1.333 to 1.343,the SPR wavelength shifts from 575.05 to 472.5 nm.The sensitivity is up to 10255 nm/RIU.Therefore,this is a proposal to achieve the ultra-high sensitivity refractive index sensing.A fiber-optic nano-displacement sensor based on SPR is demonstrated.The displacement sensing head consists of a SMF with plasmonic facet and a CPR-SMF with an air gap.The performance of the sensor can be optimized by choosing a combination of gold film thickness of 40 to 50 nm and a residual cladding thickness of 100 to 150 nm.The SPR wavelength shifts from 884.62 to 585.88 nm when varying the displacement from 0.5 nm to 10 nm.The sensitivity is 31.45 nm/nm.Thus,it is feasible to achieve high sensitivity nano or angstrom displacement measurement.A T-structure fiber-optic refractive index sensor based on SPR is investigated.The result show that the SPR wavelength shifts towards longer wavelength with the refractive index increasing.The SPR wavelength is consistent with the refractive index in a quadratic.The best sensitivity can be up to 6656nm/RIU,and the measurement range is 6.67×10-2RIU.The sensor can be extended and applied to multi-channel optical sensor applications combined with micro-fluid technologies.