Research On Structure Design,Preparation Process And Post-Processing Technology Of Anti-Resonance Negative Curvature Hollow Core Fiber

Traditional solid-core optical fibers have become the bottleneck of optical fiber communication technology due to their intrinsic properties such as absorption,dispersion,non-linearity,and low damage threshold.And traditional solid-core fibers also show limitations due to the materials in some special application fields.Hollow-core fibers provide a perfect solution to solve the bottlenecks of traditional solid-core fibers.Among them,the anti-resonance negative-curvature hollow-core fiber is a new type of hollow-core fiber that has been proposed recently.Due to its unique advantages,it has quickly become a hot topic in recent years.However,the research of anti-resonance negative-curvature hollow-core fiber is still in the early stages.In order to promote the commercial application of anti-resonance negative-curvature hollow-core fiber,the structure design,preparation process and post-processing technology of anti-resonance negative-curvature hollow-core fiber were investigated in this paper based on the former work.Firstly,based on the research status of anti-resonance negative curvature hollow-core fiber,there are few researches on the structure design with excellent performance and easy preparation,a double negative-curvature anti-resonance hollow-core fiber was proposed.Its confinement loss is reduced by about 3 orders of magnitude compare to the structure of single-layer 6-tubes,and the minimum confinement loss can reach or even exceed the loss of nested 6-tubes.In addition,its capability of high-order mode suppression is more than 200 times higher than the reported researches.The high-order mode loss of proposed fiber in the entire transmission band is more than 100 dB/m,which proves that the proposed fiber has a strong capability of single-mode operation with large-mode field.At the same time,due to the particularity of the structure,in the process of preparation,the non-uniform gaps between the tubes can be completely avoided,and the difficulty of preparation is reduced.The reported researches on anti-resonance negative curvature hollow-core fiber mainly focus on structural design and application,and there are few researches on fiber preparation.The theoretical and experimental researches on the preparation technology of anti-resonance negative curvature hollow-core fiber were investigated in this paper.A drawing model of anti-resonance negative curvature hollow core fiber was deduced,and the key process parameters in the fiber drawing process were confirmed as the width of hot zone and feed speed of preform.The principle that the cross-sectional area ratio between jacket and capillaries is constant was obtained,which completed the drawing model.According to the drawing model,suitable jacket and capillaries were selected.A nodeless anti-resonance negative curvature hollow core fiber was prepared by using the proposed preparation method which improve the uniformity of the structure.The structural parameters of the prepared hollow core fiber are consistent with the calculation results of the drawing model.At last,due to the special structure of the anti-resonance negative curvature hollow-core fiber,its post-processing technology is different from the conventional fiber,and there are few researches on the post-processing technology of this fiber.And the post-processing technology of anti-resonance negative curvature hollow-core fiber was investigated in this paper.In order to fill the blank space in the research field of coupling from large-core hollow core fiber to single-mode fiber,a coupling method was proposed.The coupling efficiency of proposed method is no longer limited by the mode field matching,in the case with large differences of core diameter,the higher coupling efficiency can be achieved through the proposed method than the traditional technology.By using the proposed coupling method,a high coupling efficiency of 50% was achieved when coupling from a hollow core fiber with a core diameter of 110 ?m to a common single-mode fiber.The coupling efficiency is improved by an order of magnitude compared with direct coupling,the coupling efficiency of which is less than 5%.