Research On Surface Plasmon Resonance Temperature Sensor Based On Photonic Crystal Fiber

Photonic crystal fiber,due to its flexible structural design,high nonlinearity,high birefringence,and other characteristics,combines metal surface plasma technology with photonic crystal fiber technology to form a photonic crystal fiber surface plasma sensor with high sensitivity and real-time detection.In recent years,it has received high attention from researchers and has published many scientific research results.It has potential research value in many sensing fields such as refractive index,temperature,and biomedical applications.It is of great significance to study the optical fiber temperature sensor based on Surface plasmon resonance photonic crystal.In this paper,a double-layer structure double-sided cast D-type photonic crystal fiber is designed.The fiber has three side cast planes.The side cast planes are coated with two metal materials with different dielectric constants,silver film and copper film,respectively,as the first layer of the sensor.The metal film is coated with a layer of silicon dioxide material to prevent metal oxidation.The cladding of the photonic crystal fiber is composed of air holes arranged in a regular hexagon and air holes arranged in a regular octagon,The structural parameters of temperature sensors with different metal coating layers were studied using Comsol simulation software,and the air hole diameter and metal film thickness were optimized.For sensors coated with metal silver film,the outer air hole diameter d₁=1μm.Inner layer small air hole diameter d₂=0.5μm and the thickness of the metal film is t _Ag=35 nm,the sensing performance is the best,with a temperature measurement range of 0-120℃,a maximum sensitivity of-7.99nm/℃,and a temperature resolution of 3.87×10^（-3）℃;For sensors coated with metal copper film,the outer air hole diameter d₁=1μm.Inner layer small air hole diameter d₂=0.5μm and the thickness of the metal film is t _Ag=40 nm,the sensing performance reaches the optimal level,with a temperature measurement range of 10-120℃,a maximum sensitivity of-3.24 nm/℃,and a temperature resolution of 4.56×10^（-3）℃。The double-sided D-type photonic crystal fiber surface plasmon sensor designed in this article has the characteristics of wide temperature measurement range,simple structure,easy preparation,and high temperature sensitivity.It has good application scenarios in the field of temperature sensing.