水下无线光通信（UWOC）具有带宽高、功耗体积小等优势，将在海洋监测与调查领域发挥重要作用，但传输距离是其最大短板。本项目拟探索使用二维单光子探测器阵列结合信号处理技术大幅提高水下蓝绿激光通信距离的可行性。我们提出单光子二维分集接收这一新概念，针对制约UWOC传输距离与可靠性的主要因素及基于单光子探测和分集接收技术的应对策略进行深入的理论分析、建模仿真与实验研究。在解决多像素光子计数器（MPPC）光电响应的数理统计特性和动态微弱光信号的可靠接收两个关键科学问题的基础上，开展MPPC的光电转换特性、水下动态信道分析与建模、二维分集接收机理与优化、长距离UWOC系统仿真、实验验证五个方面的前沿探索。实验验证所设计的基于单光子探测的UWOC系统在速率为100Mbps时传输距离可达20个衰减长度（AL），在速率为1Mbps时传输距离可达30个AL。

The underwater wireless optical communication (UWOC) features high bandwidth, small volume and power consumption. It will play an important role in such fields as ocean monitoring and survey. However, the transmission distance of UWOC is normally quite limited. In this project, we intend to explore the feasibility of using two-dimensional single-photon detector array and signal processing to significantly improve the distance of underwater wireless blue-green laser communication. We propose a novel concept of two-dimensional single-photon diversity reception. Aiming at the main factors restricting the transmission distance and reliability of a long-distance UWOC system as well as possible solutions, we will conduct a comprehensive theoretical study, modeling and simulation as well as experimental study. On the basis of solving the two key scientific problems, namely the mathematical statistics characteristics of the photoelectric response for the Multi-pixel Photon Counter (MPPC) as well as the reliable reception of dynamic and weak optical signals, we will carry out the exploration from the following five aspects: the photoelectric conversion characteristics of MPPC, the analysis and modeling of the dynamic underwater channel, the mechanism and optimization of two-dimensional diversity reception, the simulation of long-reach UWOC system, and the experimental demonstration. Combined with theoretical research, we will carry out experimental research to verify the performance of designed UWOC system based on single-photon detection, in which the transmission distance is expected to reach 20 attenuation length (AL) at a bit rate of 100 Mbps and 30 AL at 1 Mbps.