Research On Surface Plasmon Resonance Sensor Based On Tapered Fiber

Optical fiber sensor based on surface plasmon resonance is an emerging sensor,which has the advantages of high sensitivity,high resolution,fast response speed,strong anti-interference ability,etc.,and has a broad application prospect in environmental monitoring,biomedicine and other fields.Based on the combination of evanescent field excitation characteristics of tapered fiber and surface plasmon resonance technology,a surface plasmon resonance sensor based on tapered fiber is designed and optimized,and tapered fiber tapping process,coating process and sensor test system are explained in detail.The specific research content is as follows:This paper designs a surface plasmon resonance sensor based on a tapered fiber.Theoretically,the total reflection coefficient of the tapered fiber SPR sensor is calculated by combining the light propagation theory and the fiber SPR theory in the tapered fiber.The influence of the taper ratio of the tapered fiber,the length of the sensing area and the thickness of the metal film on the sensor performance was analyzed using FDTD Solutions,It is concluded that the performance of the sensor is optimal when the taper ratio of the tapered fiber is 4.5,the length of the sensing area is 15 mm,and the thickness of the silver film is 50 nm.The optimal structure of the tapered fiber probe SPR sensor was simulated between the background refractive index of 1.33 ? 1.40.The sensitivity of the tapered fiber probe SPR sensor reached 3044 nm / RIU.A tapered optical fiber probe SPR sensor with a dielectric reinforced structure is proposed.A titanium dioxide film is coated on the tapered waist of the tapered probe,so that the sensitivity of the tapered fiber probe SPR sensor reaches 6023.6nm /RIU,which greatly not only greatly improved the sensitivity of the sensor and can achieve long wavelength range measurement.The optical fiber fusion splicer is used to adjust the heating duration by setting the re-discharge time of the optical fiber fusion splicer and to change the applied tensile force by changing the weight at the end of the optical fiber.Six groups of experimental parameters are selected for comparison.When re-discharge time is 2000 ms,the weight is 8.764 g,a tapered optical fiber that meets the experimental requirements can be produced.A silver film was coated on the cone waist of the tapered fiber by magnetron sputtering,and a surface plasmonresonance sensor based on the tapered fiber was fabricated.A sensor experimental test system was established.The sensitivity of the sensor was 757.1 nm / RIU by testing different glycerin aqueous solutions.The experimental results show that the surface plasmon resonance sensor based on tapered fiber has higher sensitivity,and also provides certain value for subsequent research.