Research On Photonic Crystal Fiber Refractive Index And Temperature Dual-parameter Sensor Based On Surface Plasmon Resonance

Optical fiber sensor has the advantages of compact structure,easy manufacturing process and accurate measurement.It is widely used in steel production,biological sample detection,drug analysis,food safety detection and other fields.Among them,photonic crystal fiber(PCF)has the advantages of light weight,small volume and anti-electromagnetic interference.Therefore,the combination of metal surface plasmon resonance(SPR)technology and optical fiber technology provides a new research idea and brings a new development space for the realization of high sensitivity,high reliability,miniaturization and easy integration sensors.Based on a three-layer pore structure PCF-SPR sensor with triangular lattice,starting from the PCF sensing principle,the 2D model of PCF is established by using COMSOL Multiphysics5.4,and its characteristics are simulated.The simultaneous sensing of refractive index and temperature parameters is realized.The research results are as follows:(1)In view of the influence of the preparation and internal structure of PCF on the performance parameters of PCF,the optimization process is designed.The parameters of gold nanowires,air hole spacing,central holes and holes on both sides of the central hole are optimized successively,and two kinds of PCF structures with high sensitivity and high linearity are obtained.The detectable refractive index range of the two structures is 1.35?1.45,and the central hole d_c=2.0?m,the sensitivity in y direction is-5839nm/RIU,the linearity is 0.99934,and the d_lr on both sides of the central hole is 2.0?m,the sensitivity in y direction is-4250nm/RIU,and the linearity is 0.9989.(2)By comparing the parameters of the above two structures,a structure with a good quality factor(FOM)is selected,which can simultaneously sense the refractive index and temperature.Through data analysis of simulation experiments,it is obtained that the sensitivity of transmission loss of structure 1 is-2640.3dB/RIU and the sensitivity of resonance wavelength is-6015.4nm/RIU when the refractive index of alcohol changes.The sensitivity of transmission loss is 1.0375dB/?when the temperature is 20-80?.The resonant wavelength loss sensitivity is 0.6796nm/?,and the transmission matrix is obtained by calculation.Finally,the experimental system is designed,which can obtain the changes of refractive index and temperature by detecting the resonance wavelength offset and transmission loss offset to realize the simultaneous sensing of dual parameters.The simulation results show that the sensor can achieve high sensitivity,small device size,good fabrication tolerance and large measurement range.This experiment provides an effective idea for the structural optimization of PCF-SPR,and provides a certain simulation experimental basis for the research of PCF-SPR two parameter sensing.