基于双耦合环辅助的低串扰6-LP光纤设计  

Design of Low Crosstalk Double Coupling Ring Assisted 6-LP Fiber

作　　者：臧鸿飞 田凤[2] 王拥军[2] Zang Hongfei;Tian Feng;Wang Yongjun(State Key Laboratory of Information Photonics and Optical Communications,School of Electronic Engineering,Beijing University of Posts and Telecommunications,Beijing 100876,China;Beijing Key Laboratory of Space-Round Interconnection and Convergence,Beijing University of Posts and Telecommunications,Beijing 100876,China)

机构地区：[1]北京邮电大学电子工程学院信息光子学与光通信国家重点实验室,北京100876 [2]北京邮电大学天地互联与融合北京市重点实验室,北京100876

出　　处：《中国激光》2022年第3期64-72,共9页Chinese Journal of Lasers

基　　金：国家重点研发计划(2018YFB180100);国家自然基金(62021005,61875248,61727817,6202780085)。

摘　　要：为了降低少模光纤中的模间串扰,提出了一种新型双耦合环辅助的少模光纤结构设计。首先用COMSOL仿真软件对6-LP光纤结构进行建模,并分析了影响模式间耦合的主要因素,然后对双耦合环结构的5个参数进行仿真分析。结果表明,在6-LP少模光纤中,LP_(21)模和LP_(02)模的有效折射率最接近,其差值是影响串扰的主要因素;该结构中LP_(21)模和LP_(02)模的最小模间折射率差为1.5×10^(-3),是同等条件下传统阶跃结构的1.88倍,少模光纤中的模间串扰问题得到有效缓解。Objective In the design of a few-mode fiber,the inter-mode coupling phenomenon is a problem that cannot be avoided.The weakly coupled mode division multiplexing system has a simple structure,low cost,and a wide range of applications.However,the inter-mode coupling phenomenon leads to instability between signal transmissions.This restricts the application of an optical fiber in media and long-distance transmissions.In a weakly coupled mode division multiplexing system where each mode or mode group is transmitted as an independent channel,the direct detection of intensity modulation can be realized and the cost is low.The key of the weak coupling mode division multiplexing technology lies in the highly selective mode excitation and the low-mode crosstalk characteristics of the few-mode fiber.The fiber mode crosstalk caused by the imperfection of the fiber and the environmental disturbance accumulates with the distance,so the transmission distance is limited,which is more suitable for short-distance application scenarios such as access networks and data centers.This paper focuses on the study of low mode coupling in the weakly coupled mode division multiplexing systems,and proposes a new type of fiber with low mode coupling,whose effectiveness is validated by simulation.Finally,a 6-LP few-mode fiber based on the dual coupling ring structure is designed.Methods Firstly,COMSOL modeling is carried out based on the step 6-LP few-mode fiber,and the main influencing factors of the coupling between modes in the 6-LP few-mode fiber are discussed.The simulation analysis shows that the key to reducing the crosstalk between modes of the few-mode fiber is to increase the effective refractive index difference between LP_(21)and LP_(02).Then,based on the electric field distributions of the 6 modes,a new type of dual coupling ring assisted few-mode fiber structure is designed.After COMSOL modeling,the simulation analysis is performed on the five specific parameters of the double coupling loop structure,and the change trend of the

关 键 词：光通信 模分复用 少模光纤 双耦合环结构 光纤特性 

分 类 号：O436[机械工程—光学工程]