轨道角动量是一个基本物理量。在物理学和光通信学科交叉领域，将轨道角动量引入光通信可以提供新维度资源，有望解决光波已有维度资源开发殆尽而显现的容量危机。本项目通过对轨道角动量光通信新机制、新器件、新技术和新应用的探索研究，旨在实现高分辨、宽带宽、低损耗、可扩展、高效率和高密度的分数阶轨道角动量光通信。项目围绕“如何实现轨道角动量光子集成收发”和“如何实现多个轨道角动量高效(解)复用”两大关键问题展开，深入开展高密度分数阶轨道角动量光通信的理论基础、核心器件、关键技术及系统应用研究。首先，提出利用超颖表面结构对光场空间幅度和相位进行操控并进行基础理论及特性研究；其次，设计研制轨道角动量超颖表面结构光子集成器件；然后，研究多轨道角动量高效同步(解)复用和并行检测关键技术及高密度分数阶轨道角动量光通信的关键技术；最后，利用研制的超颖表面结构光子集成器件开展高密度分数阶轨道角动量光通信系统实验研究。

Orbital angular momentum (OAM) is a fundamental physical quantity. In the interdisciplinary research areas between physics and optical communications, it is possible to provide a new dimension resource by introducing OAM into optical communications, which might address the capacity crunch due to the excessive exploitation of all existing dimensions of optical waves. In this project, by exploring new mechanisms, new devices, new technologies, and new applications in the fields of OAM optical communications, it is intended to achieve fractional OAM optical communications with high resolution, broad bandwidth, low loss, good scalability, high efficiency, and high density. The research works start from two key scientific issues: how to implement the integrated transmitter and receiver of OAM and how to achieve high efficiency (de)multiplexing of multiple OAMs. Deep researches are carried out focusing on the basic theories, core devices, key technologies, and system applications of high density fractional OAM communications. Firstly, the manipulation of amplitude and phase of spatial optical filed utilizing metasurface structures is proposed and the basic theories and characteristics are studied. Secondly, the OAM photonic integrated devices based on metasurface structures are designed and fabricated. Thirdly, two key technologies are investigated: 1) high efficiency simultaneous (de)multiplexing and parallel detection of multiple OAMs; 2) high density fractional OAM communications. Finally, using the fabricated photonic integrated devices based on metasurface structures, system experiments of high density fractional OAM communications are studied.