Study On Refractive Index Sensing Characteristics Of Dual-core Fiber Based On Surface Plasmas

With the development of modern optoelectronic technology,fiber optic sensors are increasingly used in industrial and agricultural production,military equipment,environmental monitoring,biochemistry and many other fields due to their simple structure,high temperature resistance and electromagnetic interference resistance.Refractive index parameter is a key parameter in water quality monitoring sensing and biochemical index evaluation.How to use optical method to quickly and accurately measure liquid refractive index is a research hotspot in the field of fiber optic sensing in recent years.In view of the above actual engineering requirements,this paper proposes a D-type dual-core fiber refractive index sensor based on the principle of surface plasmon resonance,and conducts in-depth theoretical simulation analysis and a lot of experimental research work on the refractive index sensing scheme.The main contents include:Firstly,based on a large number of domestic and foreign related literatures,the research status and significance of fiber refractive index sensing technology are introduced.The surface plasmon resonance technology is analyzed,and the mechanism,method and advantages and disadvantages of the surface plasmon resonance technology are analyzed.A detailed discussion has been made.Secondly,the principle of surface plasmon resonance is studied in theory.The principle of evanescent field,the principle of surface plasma wave and the principle of dual-core fiber coupling are analyzed.The mechanism of surface plasmon resonance and refractive index sensing are discussed.Model establishment and analysis methods.Thirdly,using COMSOL Multiphysics software to carry out in-depth simulation analysis and numerical calculation of the refractive index sensing characteristics of D-type dual-core fiber,and study the polishing angle,polishing depth,and polishing depth in the side-draw D-type dual-core fiber structure.The relationship between the thickness of the metal film and the refractive index of the solution to be measured yields a correlation law.Finally,based on the theoretical analysis,an in-depth experimental study was carried out to form the process flow and processing method for the D-type dual-core fiber refractive index sensor.A large number of sensing experiments were carried out on the prototype of the refractive index sensor,and the experiment was carried out.The results were analyzed and the conclusions of the study were obtained.The research content of this paper has valuable reference significance for the design and practical engineering application of the new fiber refractive index sensor.