少模光纤复用传输模式损伤机理与补偿技术

Currently, the network bandwidth requirements are increasing explosively without any interruption, while the exhausted potential of single mode fiber transmission capacity are approaching the nonlinear Shannon limit. Under this background, few mode fiber based mode-division multiplexing (MDM) has been viewed as the most promising candidate for single-mode fiber beyond transmissions with ultra-large capacity, long-haul and high spectrum efficiency requirements. However, the transmissions performance of few mode fiber based MDM systems are severely limited by complicated mode dependent effects and impairments. This project aims to explore the mechanism and key compensation techniques of mode impairments. By incorporating the spatial mode division extended nonlinear Schrǒdinger equation and mode coupling theory, the fundamental theoretical model of the nonlinear transmission process and mode impairments mechanisms will be established. By proposing innovative techniques including dynamic mode coupling controlling, transmitter-based adaptive mode modulation and receiver-based digital back propagation of mode-multiplexed signals, the key mode impairments including mode dependent gain and loss, differential mode group delay and inter-modal nonlinearity can be effectively suppressed and compensated. System level simulation and experiments verifications will be carried out for elaborating the mode impairments mechanisms and substantiating the proposed compensation methods. The outcomes of this project will construct the theoretical and technical foundations for realizing breakthroughs for few mode fiber based MDM applications with ultra-high spectrum efficiency and long-haul transmission reach.

在骨干网络带宽需求持续猛增、单模光纤传输潜力发掘殆尽、逼近非线性仙农容限的背景下，基于少模光纤的模分复用技术成为后单模光纤时代超大容量、超长距离、高谱效传输最具潜力的实现方式之一，具有广阔的发展空间和应用前景。本项目针对长距离少模光纤复用传输所面临的模式效应复杂、模式损伤严重、传输性能遭遇瓶颈的根本问题，探索模式损伤作用机理与损伤补偿的关键技术。通过引入空间维度扩展的非线性薛定谔方程和模式耦合理论，建立非线性传输过程和模式损伤作用的基础理论模型；通过动态模式耦合控制、发送端自适应模式信号调制、接收端模式信号数字背向传输等创新技术，实现对模式相关增益/衰减、差分模式群时延和模间非线性串扰等主要损伤因素的全面补偿抑制，采用系统仿真和实验手段对损伤机理和关键技术进行验证，为突破少模光纤模分复用系统性能瓶颈、实现超高谱效、长距离复用传输奠定理论和技术基础。

在骨干网络带宽需求持续猛增、单模光纤传输潜力发掘殆尽，逼近非线性仙农容限的背景下，基于少模光纤的模分复用技术正成为后单模光纤时代超大容量、超长距离、高谱效传输最具潜力的实现方式之一，具有广阔的发展空间和应用前景。本项目针对长距离少模光纤复用传输所面临的模式效应复杂，模式损伤严重、传输性能遭遇瓶颈的根本问题，探索模式损伤作用机理与损伤补偿的关键技术。.项目组设计了适合模分复用传输的低耦合、低非线性少模光纤；建立非线性传输过程和模式损伤作用的理论模型；实现了包含模式群时延、模式相关增益/衰减，强、弱机制下的线性模式耦合、模内/模间非线性等损伤效应在内的模分复用系统仿真平台，支持对上述模式损伤的分离式/结合式仿真及基于单载波、多载波等调制和数字信号处理。在此基础上，发现了模式信道调制格式各异条件下的模式串扰新机理。设计了基于注水原理的模式功率控制、自适应模式调制、自适应模式损伤均衡、模分复用的空时-空频编码和分集接收等模式损伤补偿算法，并提出了模分复用系统中基于Stokes空间的调制格式无关的解复用算法，并通过系统仿真和试验进行了验证。.相关研究发表SCI论文7篇，Ei论文3篇，已获授权国家发明专利3项，授权实审中的国家发明专利4项，已培养博士研究生2人，硕士研究生4人，为实现超高谱效、长距离复用传输奠定理论和技术基础。