| In recent years,microstructured optical fiber has been paid more and more attention by researchers in many fields due to its excellent optical properties and flexible cross-section structure.Especially,it can break through the limitations of traditional optical fiber in sensing.In this thesis,two kinds of microstructure optical fiber sensors based on surface plasma resonance effect are designed and simulated by COMSOL Multiphysics software.Moreover,ANSYS Polyflow software is used to simulate the melting and stretching process of the microstructure prefabricated rods,and the influences of different parameters on the neck area of the prefabricated rods have been analyzed.Firstly,an ex-centric core microstructured optical fiber refractive index sensor is put forward,and the SPR effect is stimulated by external gold nanowires.The x polarization direction of the fundamental mode electric field is determined as the main research object.The change of resonance intensity and the red shift trend of resonance wavelength are analyzed.By changing the refractive index of the liquid to be measured,the real part and imaginary part curves of the effective refractive index of the fundamental mode and SPW mode,the sensing properties are determined..The average spectral sensitivity is 7428nm/RIU,and the maximum spectral sensitivity is 14200 nm/RIU.In addition,the refractive index resolution is 1.72×10-5and 7.04×10-6,respectively.When the refractive index is 1.37 to1.39,the quality factor is higher.Secondly,a microstructure optical fiber temperature sensor embedded with silver nanowires based on SPR was designed and studied.The finite element method is used to analyze the limit loss curve.Synthetic ionic liquid was introduced as a temperature-sensitive liquid to expand the temperature range,and hydrofluoric acid can be used to corrode the side air hole to form the embedded channel of the silver nanowires.The feasibility of setting an extra layer of air holes in the interior to improve the sensing performance at low temperature is discussed.In addition,by comparing the changes of spectral sensitivity between the single fiber and the double fibers,it is found that the average temperature sensitivity increases to3.166nm/?,and the maximum temperature sensitivity reaches 5nm/?,increasing by55.73%and 28.2%respectively,and the temperature resolution is 0.02?.Moreover,the fitting curve effect of the wavelength of peak loss of the double fiber structure is also better than that of the single fiber structure.Finally,the influences of temperature,inner and outer radius,length of heating zone,feeding speed and stretching speed on the collapse rate of the final structure is studied through numerical simulation.And the method of changing the surface temperature of the internal air hole is proposed to control the collapse rate relatively freely.It is found that the change of the radius of the orthogonal direction and offset rate of the air hole will decrease with the decrease of the initial radius and the increase of the distance.In addition,it is also beneficial to improve the above results when the tensile environment temperature is reduced.It is indicated that the tensile simulation of microstructure prefabricated rods using ANSYS Polyflow has a certain reference value for the experiment,which can help to optimize the drawing parameters and improve the success rate of fabrication. |
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