独立反谐振纤芯低损耗光子带隙光纤  

Low-Loss Isolated Anti-Resonant Core Photonic Bandgap Fiber

作　　者：高福宇 徐小斌[1] 宋凝芳[1] 李伟 朱云浩 刘嘉琪 梁田田 Gao Fuyu;Xu Xiaobin;Song Ningfang;Li Wei;Zhu Yunhao;Liu Jiaqi;Liang Tiantian(School of Instrumentation and Optoelectronic Engineering,Beihang University,Beijing 100191,China;Ruiguang Xintong Technology Co.,Ltd.,Wuhan 430074,Hubei,China)

机构地区：[1]北京航空航天大学仪器科学与光电工程学院,北京100191 [2]锐光信通科技有限公司,湖北武汉430074

出　　处：《中国激光》2022年第19期168-174,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(61935002);国防科技重点实验室基金(2021-JCJQ-LB-070-23)。

摘　　要：光子带隙光纤具有弯曲损耗小、对环境变化不敏感等优点,是极端应用条件下高稳定光纤陀螺的理想光纤。但光子带隙光纤的传输损耗大,缺乏适用于光纤陀螺的低损耗、小模场光子带隙光纤。提出了独立反谐振纤芯光纤构型,将纤芯与包层进行空间隔离,利用纤芯壁反谐振效应抑制基模与表面模的耦合,利用反谐振与光子带隙双重效应将光限制在纤芯中传输,从而实现了光子带隙光纤小模场、低损耗的特性。理论分析结果表明,所提出的光纤构型可将模场直径为~8μm的光子带隙光纤的损耗降低至<3.5 dB/km。采用两步法制备的光纤基本复现了设计结构,但占空比与设计值存在偏差,导致带隙偏移,实验测得所制备光纤的最小损耗为~25 dB/km@1200 nm。Objective The advantages of photonic bandgap fiber(PBF)in terms of temperature,radiation,magnetic field,and other aspects of environmental adaptability make it an important development direction of fiber optic gyroscope technology.PBF has attracted extensive attention from research institutions worldwide.However,the fiber loss of sevencore PBF which is suitable for fiber-optic gyroscopes is large,and the PBF cannot meet the low-loss application requirements of fiber-optic gyroscopes for fibers.Methods The PBF loss is mainly caused by the coupling between the fundamental mode and surface modes of the core wall,and the scattering loss caused by the roughness of the inner wall of the fiber core.In this study,an isolated antiresonant core photonic bandgap fiber(IAC-PBF)is developed,in which the fiber structure can isolate the core from the cladding,thereby the coupling between the fundamental mode and surface mode is suppressed through the anti-resonant effect of the core wall.An IAC-PBF structural model is established and the loss of the fiber is calculated using the F parameter method.The optimized fiber structure is obtained by scanning the structural parameters.The mode characteristics of the fiber and the loss reduction principle are determined by mode coupling analysis,and it is verified that the proposed fiber structure has low theoretical loss.Finally,the fiber is fabricated using the stacking-drawing method.Although the core size is small and the bandgap is offset,the feasibility of low-loss fiber is proved.Results and Discussions The IAC-PBF structure is proposed in this article(Fig.1).Its cladding structure is the same as that of 19-cell PBF,and the photonic crystal structure is still formed through the periodic arrangement of hexagonal air holes to generate the photonic bandgap effect to prevent light leakage from the cladding.A hexagonal anti-resonance layer is used to isolate the core and cladding layers spatially.This reduces the mode coupling and scattering loss.The mode field diameter is approximatel

关 键 词：光纤光学 光纤设计 光子带隙光纤 低损耗 小模场直径 

分 类 号：TN253[电子电信—物理电子学]