自由空间连续变量量子密钥分发理论与实验研究

Continuous-variable quantum key distribution (CVQKD) has become an important way to implement quantum cryptography communication, and it is attracting more and more attention by academic researchers and industrial community in recent years. So far, almost all of the researchers are focusing on the study of fiber-optics CVQKD, and due to the intrinsic loss of fiber-optics channel, the secure distance and secret key rate of fiber-optics CVQKD is quite limited. While free-space quantum channel has the excellence of low losses, high stability, and can be transit by the space platform, which makes it to be generally considered as a feasible option for the global quantum cryptography communication. In this application, we will study the theoretical and experimental techniques of CVQKD based on free-space quantum channel, and solve the core theoretical and key experimental technique problems in the aspects of optical coding and modulation, optical tracking, pointing, and coupling, and security monitoring experimental techniques. Then maximize the advantages of CVQKD technique and construct a good foundation for free-space CVQKD, and thus provide technical reference for the construction of long-distance, inter-regional global quantum cryptography communication network.

连续变量量子密钥分发（CVQKD）技术近年来已经成为一种重要的量子保密通信手段，受到国内外学术界和产业界的广泛关注。目前国内外针对CVQKD的研究都基本集中在光纤传输技术方面，而光纤CVQKD因为其固有传输损耗很大程度上制约了其安全传输距离及安全密钥率。由于自由空间量子信道具有损耗小且可通过空间平台中转的优点，被认为是实现全球量子保密通信网络的有效手段。本项目将致力于研究自由空间信道传输下的CVQKD理论及实验技术，解决其在光编码调制、光跟踪瞄准与耦合以及系统安全监控等方面的核心理论及关键实验技术问题，最大化发掘CVQKQ在高密钥率等方面的技术优势，奠定我国在该领域的良好基础，为建立长距离、跨区域全球量子保密通信网络提供技术参考。

连续变量量子密钥分发（CVQKD）技术近年来已经成为一种重要的量子保密通信手段，受到国内外学术界和产业界的广泛关注。目前国内外针对CVQKD的研究都基本集中在光纤传输技术方面，针对自由空间的CVQKD还鲜有研究。本项目研究了自由空间信道传输下的CVQKD理论及实验实现关键技术，解决了自由空间信道下CVQKD的理论协议设计、连续变量信号传输、过噪声抑制、光编码调制、数据后处理以及系统实际安全性等方面的问题，填补了国际上针对自由空间CVQKD实验实现的多项技术空白，如大气效应对连续变量信号的影响、自由空间CVQKD相位及偏振补偿、参数评估、本地本振编解码以及抗背景光噪声能力的机理及实验验证等，推进了自由空间CVQKD技术的发展并奠定了我国在该领域良好的研究基础，为建立长距离、跨区域全球量子保密通信网络提供了理论及应用技术基础。