Research On Surface Plasmon Resonance Refractive Index Sensor Based On D-type Optical Fiber

Surface plasmon resonance fiber sensor is an emerging sensor,which has the advantages of good stability,small volume,high precision and strong anti-electromagnetic interference and it is widely used in environmental monitoring,biomedical science and other fields.Due to its unique optical properties,D-type optical fibers which based on evanescent field structures can be well combined with surface plasmon resonance.This paper optimizes the design of a D-type optical fiber surface plasmon resonance sensor and the sensor was made.The manufacturing process and test system of the sensor are introduced.The main work is as follows:In this paper,a D-type optical fiber surface plasmon resonance sensor is designed.In theory,the transmission coefficient of D-type optical fiber sensor is calculated by the principle of multi-layer film reflection,and the influence of residual cladding thickness,metal film thickness and surface roughness of metal film on sensor's performance is simulated by FDTD Solutions to obtain an optimized structure of D-type optical fiber sensor.The sensitivity of the sensor based on gold film reached 2851nm/RIU,and the sensitivity of the sensor based on silver film reached 3319nm/RIU between the refractive index of the medium of 1.33-1.39.A dualchannel surface plasmon resonance sensor based on double D-type optical fiber is proposed.Coating different metal films on both sides of the double D-type optical fiber can realize twochannel measurement of signals and improve the utilization of sensors.In this paper,a silver film is coated on the polishing position of the D-type optical fiber by magnetron sputtering and the thickness of the silver film is 50 nm.A D-type optical fiber surface plasmon resonance sensor was made and the sensor was packaged.A D-type optical fiber sensor test system was built to test the performance of the sensor.The sensitivity of the sensor was 3169 nm/RIU by detecting the refractive index of different concentrations of glycerol solution.The experimental results show that the developed D-type optical fiber SPR sensor has high refractive index sensitivity,which provides a reference for subsequent experiments.