Design And Characteristics Study Of Photonic Crystal Fiber Sensor Based On Surface Plasmon Resonance

With development of Surface Plasmon Resonance(SPR)sensing technology,PCF-SPR sensors have become increasingly mature,and have a huge market in the fields of biomedicine and environmental monitoring.In this paper,a quasi-D-type PCF-SPR sensor is designed,and its sensing characteristics are analyzed using COMSOL Multiphysics,a profesional numerical analysis software,and its structural parameters are optimized.The main content of the paper is listed as follows:(1)The research background,research progress and development trend of PCF-SPR sensors are introduced.The PCF-SPR sensors have many unique advantages compared to the traditional optical fiber sensors.With continuous maturity of the photonic crystal fiber drawing technology,application of the PCF-SPR sensors will be more extensive in the near future.(2)The basic theory of surface plasmon resonance-based sensing technology and photonic crystal fiber are introduced.The sensing mechanism of the photonic crystal fiber sensor working on the basis of SPR technology is analyzed in detail.(3)Introduced the numerical simulation method commonly used in the PCF,Finite Element Method(FEM).The software of COMSOL Multiphysics and basic simulation steps are introduced.(4)Proposed the model of quasi-D PCF-SPR sensor.The manufacturing process of the sensor is simplified by moving the core of the photonic crystal fiber up.Compared to the general D-type PCF-SPR sensor,the sensor designed in this paper is greatly enhanced in structure.Two elliptical air holes are introduced on both sides of the core,which increases the birefringence effect in the Y-direction,and enhances the confinement loss of the fundamental mode.The use of ITO film as the sensing material realizes the functioning of the sensor in the near-infrared waveband and increases the applicability of the sensor.Covering a layer of graphene on the surface of the ITO film,and using the special structure of graphene itself,increases the sensor's ability to adsorb large biomolecules,so that the sensor can be more extensively used in the field of biological monitoring.(5)The proposed sensor model is optimized on the basis of numerical simulation.By optimizing parameters such as ellipticity,polishing depth,ITO film thickness,and graphene layers,the designed sensor achieves excellent performance.The sensor's refractive index is ranging from 1.21 to 1.32,the maximum sensitivity reaches 12000nm/RIU(Refractive Index Unit,RIU),and the maximum resolution is 8.33×10^-6RIU.