低损耗太赫兹空芯反谐振光纤的设计  

Design of Low-Loss Terahertz Hollow Core Anti-Resonant Fibers

作　　者：汪静丽[1] 李楚凡 万洪丹[1] 陈鹤鸣 Wang Jingli;Li Chufan;Wan Hongdan;Chen Heming(College of Electronic and Optical Engineering&College of Flexible Electronics(Future Technology),Nanjing University of Posts and Telecommunications,Nanjing 210023,Jiangsu,China;Bell Honors School,Nanjing University of Posts and Telecommunications,Nanjing 210023,Jiangsu,China)

机构地区：[1]南京邮电大学电子与光学工程学院、柔性电子(未来技术)学院,江苏南京210023 [2]南京邮电大学贝尔英才学院,江苏南京210023

出　　处：《光学学报》2025年第1期20-28,共9页Acta Optica Sinica

基　　金：国家自然科学基金(12174199,61571237);江苏省自然科学基金(BK20221330,BK20151509)。

摘　　要：本文提出了一种太赫兹空芯反谐振光纤,9个由椭圆、圆以及直杆组合而成的嵌套结构均匀分布于最外侧起结构支撑作用的圆环上构成包层,纤芯为空气芯。一方面,利用反谐振反射效应导光进一步减小限制损耗;另一方面,包层结构采用高电阻率硅,有利于减小光纤的有效材料损耗。此外,对光纤结构进行优化,可使其在较宽的带宽范围内实现低损耗传输以及较好的光纤性能。采用有限元法结合完美匹配层边界条件对光纤进行建模仿真,结果表明:在宽的带宽范围(0.84~1.56 THz)内,传输损耗(TL)均低于10^(-1)dB/m,且在0.98~1.44 THz频段,TL低至10^(-4)dB/m,频率为1.10 THz时达到最低值2.80×10^(-4)dB/m;光纤具有近零色散且色散平坦[(0.02139±0.08824)ps·THz^(-1)·cm^(-1)];有效模场面积大,达到~10~7μm^(2)量级;此外,还具有较好的抗弯曲性,弯曲半径大于35 cm时,弯曲损耗小于8.96×10^(-3)dB/m。该光纤为高性能的低损耗太赫波传输波导设计提供了参考。Objective In practice,the environment and atmospheric conditions of free space influence the transmission of terahertz waves,leading to issues such as dispersion and large transmission loss(TL).Hollow core fibers emerge as promising for terahertz wave transmission because of their broad application potential.However,current hollow core photonic bandgap fibers(HC-PBGFs)for terahertz wave transmission have issues including poor mode purity,elevated surface scattering loss,and complex manufacturing processes.In contrast,hollow core anti-resonant fibers(HC-ARFs)have a simpler structure and are easier to fabricate,making them a research focus.Nevertheless,reported HC-ARFs still have room for improvement in TL and some fiber properties.To overcome these limitations,we have designed a novel terahertz HCARF structure.By carefully designing the geometric configuration of the nested structure in the cladding,increasing the number of nested layers,and using high-resistivity silicon with minimal absorption loss as the fiber material,we further reduce TL and dispersion and thus enhance the overall fiber performance.This fiber provides a valuable reference for the development of high-performance,low-loss terahertz wave transmission waveguides.Methods The anti-resonant reflection waveguide model combined with the suppression coupling theory comprehensively explains the guiding mechanism in HC-ARFs.These fibers mainly use the anti-resonant effect to confine energy within the fiber cores.First,we design the nested structure that constitutes the cladding of HC-ARF.Unlike typical fiber structures using circular nested tubes(fiber structure A),elliptical nested tubes(fiber structure B),and double-layer elliptical nested tubes(fiber structure C),the innovative nested configuration integrating ellipses,circles,and straight rods has superior performance in constructing the fiber cladding.In addition,the nine nested structures in the cladding are arranged without nodes,which avoids the resonance of nodes between nested structures affect

关 键 词：空芯反谐振光纤 太赫兹 传输损耗 色散 

分 类 号：O436[机械工程—光学工程]