Design And Characteristic Research Of Near-Infrared Long-Wave For Hollow Core Anti-Resonant Fibers

With the development of near-infrared long-wave in medical,industrial and so on,the demand for near-infrared long-wave(1.5～2.5μm)fibers have gradually increased.At present,the loss of all existing fibers in this band are high.Among them,solid-core fibers mostly use arsenic-sulfur-based materials,and the thermal damage threshold is low.Traditional hollow-core fibers are mostly made of metal dielectric films,which have complicated fabrication technology and poor chemical stability.In recent years,hollow core anti-resonant fibers have become a research hotpot of near-infrared long-wave band due to its simple fabrication technology,low loss,high damage threshold of quartz substrate material and low cost.This paper uses the full vector finite element method to study the characteristics of the hollow core anti-resonant fiber.Finally,a kind of hollow core anti-resonant fiber with low transmission loss,low bending loss and good single-model performance for near-infrared long-wave transmission is designed.Firstly,the research background and significance of this paper is briefly introduced.In addition,the advantages of near-infrared long-wave transmission in hollow core anti-resonant fiber,the current research status of near-infrared long-wave hollow core anti-resonant fibers at home and abroad are explained.The light guide mechanism of hollow core anti-resonant fibers and the simulation method of hollow core anti-resonant fibers are introduced.Secondly,the loss of near-infrared long-wave hollow core anti-resonant fibers are studied.Besides,the influence of the parameter changes of the hollow core anti-resonant fibers on its loss characteristics are discussed.After parameter-by-parameter optimizing step by step,above all the anti-resonant thickness of the applied band is determined.In the next work,after exploring the effect of core diameter changing on confinement loss,the diameter and the gap of fibers are determined.Furthermore,the positive and negative curvature of the fiber is researched.In the end,the effect of multi-layer anti-resonant is studied by nesting tube in the cladding tube.Thirdly,the single-mode properties of the near-infrared long-wave hollow core anti-resonant fibers are studied.The process of coupling between the inner cladding tube mode and the higher-order mode under the traditional fiber structure,together with the outer cladding tube mode and the higher-order mode under the improved structure are finally studied.As well as,the effect of nesting structure on single-mode properties.Finally,the bending characteristics of the near-infrared long-wave hollow-core anti-resonant fibers are studied.Moreover,the influence of bending on fibers are studied,including the mode field,bending loss,and single mode.As a consequence,a low transmission loss,low bending loss,and good single-mode performance of near-infrared long-wave hollow core anti-resonant fibers is designed.