Highly efficient excitation of LP01 mode in ring-core fibers by tapering for optimizing OAM generation  

作　　者：Chunxiang Zhang Fufei Pang Huanhuan Liu Lifei Chen Junfeng Yang Jianxiang Wen Tingyun Wang 张春香;庞拂飞;刘奂奂;陈丽飞;杨俊锋;文建湘;王廷云(Key Laboratory of Specialty Fiber Optics and Optical Access Networks,Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication,Shanghai Institute for Advanced Communication and Data Science,Shanghai University,Shanghai 200444,China)

机构地区：[1]Key Laboratory of Specialty Fiber Optics and Optical Access Networks,Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication,Shanghai Institute for Advanced Communication and Data Science,Shanghai University,Shanghai 200444,China

出　　处：《Chinese Optics Letters》2020年第2期5-9,共5页中国光学快报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.61635006,61975108,and 61605108);the Shuguang Program(No.16SG35).

摘　　要：We have demonstrated the highly efficient excitation of the linearly polarized mode(LP01)in ring-core fibers(RCFs)by tapering the spliced point between the RCF and the standard single-mode fiber(SMF)to optimize all-fiber orbital angular momentum(OAM)generation.The tapering technique has been investigated theoretically and experimentally.Before tapering,only 50%of light can be coupled from SMFs to RCFs.The modal interference spectrum with an extinction ratio(ER)of～9 dB is observed,showing that higher-order modes are excited in RCF.By tapering the spliced point,90%of light is coupled,and the ER is minimized to be～2 dB,indicating that the higher-order modes are effectively suppressed by tapering.Such tapered spliced points of RCF–SMF are further applied for all-fiber OAM generation.The efficiencies of OAM+1 and OAM?1 generation are found to be enhanced by approximately 11.66%and 12.41%,respectively,showing that the tapered spliced point of the RCF–SMF is a feasible way to optimize OAM generation.

关 键 词：ring-core FIBER single-mode FIBER ALL-FIBER orbital angular momentum generation TAPERING technology 

分 类 号：TN253[电子电信—物理电子学]