新型太赫兹光子晶体OAM光纤设计

太赫兹通信兼具微波通信和光波通信的优势，是解决通信容量紧缺难题的最有效技术手段之一。针对太赫兹波段吸收损耗严重及抗外在扰动差，难以支持长距传输问题，设计了一种基于环形光子晶体光纤(PCF)结构的新型太赫兹光纤。以现有常见材料作为光纤基底材质，通过创新光纤结构中空气孔排布方式，抵消材料高吸收损耗，以支持高性能轨道角动量(OAM)模式传输。选择最优参数，实现6个OAM模式群的高模式质量、低限制损耗和宽带宽的稳定传输。在0.2~0.9 THz宽波段内，实现模式纯度超过88.9%，限制损耗小于10^-7 dB/m。通过软件仿真实验设计，解决了太赫兹与OAM技术相结合的关键问题，为模分复用(MDM)技术在太赫兹通信系统的应用奠定了理论研究基础。

Design of new terahertz photonic crystal fiber for Orbital Angular Momentum modes transmission

Terahertz communication has the advantages of both microwave communication and optical communication, which is one of the most effective technical means to solve the problem of communication capacity shortage. In order to solve the problems of serious absorption loss and poor external disturbance resistance in terahertz band, a new terahertz fiber based on circular Photonic Crystal Fiber(PCF) structure is designed to support high performance Orbital Angular Momentum(OAM) modes transmission. The existing common materials are used as the fiber base material, and the high absorption loss of materials is offset by the innovation of hollow porosity arrangement in the fiber structure. The optimal parameters are selected to realize the stable transmission of six OAM mode groups with high mode quality, low confinement loss and wide bandwidth. The mode purity is above 88.9% and the confinement loss is below 10^-7 dB/m in the 0.2~0.9 THz band. Through simulation, the key problem of combining terahertz and OAM technology is solved, which lays a theoretical foundation for the application of Mode Division Multiplexing(MDM) technology in terahertz communication system.