Research On Photonic Crystal Fiber Filter Based On Surface Plasma Resonance

Since PCF was proposed in 1995,its value has been confirmed by numerous scientists.With its unique structure and performance advantages,PCF has attracted more and more attention in the field of optics.Due to its flexible material selection and structure design,PCF has some unique optical properties that traditional optical fibers do not have,such as strong nonlinear effect,rare dispersion characteristics,high birefringence characteristics and low bending loss characteristics.In this paper,a kind of photonic crystal fiber based on surface plasmon resonance(SPR)is designed,which makes use of its polarization characteristics,and realizes the function of polarization filtering.Surface plasmon resonance(SPR)is a physical optical phenomenon occurring at the interface between metal and dielectric.When the whole emission of light wave occurs at the interface,the evanescent wave is produced in the light scattering medium.The evanescent wave leads to the coherent oscillation of free electrons on the metal surface and the surface plasmon.The main contents of this paper are as follows:1.Firstly,the research background is introduced,then the basic concept of PCF and the research status of optical filter are explained,and then the main content of this paper is clarified.2.The theoretical methods and the surface plasmon effect of PCF are introduced.The surface plasmon effect in PCF and its development are analyzed.And the performance index of pcf-spr filter.3.A polarization filter based on two large hole PCFs is designed.The main optical characteristics are simulated by the finite element method.The filtering effect at 1.35 μm is studied by adjusting its structural parameters.The influence of changing the symmetry around the gold coated hole on the two polarization directions is also studied.This is a new idea of polarization filtering effect.These are of some guiding significance for the research and development of new photon devices.4.On the basis of the filter introduced in the previous chapter,the structure of PCF is changed and a new SPR filter with a large hole is designed.The main optical properties are also simulated by the finite element method.The filtering effect at 1.31μm is studied by adjusting its structural parameters.The influence of changing the symmetry around the gold coated hole on the two polarization directions is also studied.The designed filter has two symmetrical large holes,and the holes are coated with a layer of metal film,which greatly improves the loss.The characteristics of polarization filter are calculated by finite element method.The thickness of the metal layer and the arrangement and size of the pores near the core are discussed.The optimal structure of metal filled polarization filter in PCF is obtained.By adjusting the parameters,the loss of the filter at 1.31 μm in Y direction is 3261.7 dB/cm,while the loss in X direction is smaller.When the fiber length is set to 200μm,the extinction ratio is greater than 20 dB and the width is 1 μm.The filter has simple structure and excellent performance.