星地量子通信光链路的建立与在轨验证

Establishment and in-orbit test of optical link in satellite-toground quantum communication

星地高精度光链路的建立是进行星地量子通信科学实验的必要条件,相比常规激光通信,星地量子科学实验卫星需解决量子光和信标光能量差异极大,卫星要同时和两个地面站建立高精度光链路等特殊要求.论文基于星地量子通信的科学需求,提出了卫星对站指向和载荷自主寻的相结合的一星两站光链路建立的总体方案,采用凝视–凝视的捕获方法,实现星地的快速捕获;采用粗跟踪和精跟踪相结合的多级跟踪架构,满足星地高精度光学跟踪的需求;采用星地联合扫描和系统修正的方法,实现了星地量子光束的高精度对准.最后论文给出墨子号量子科学实验卫星在轨验证结果,实验数据表明量子科学实验卫星光链路建立的各项指标均达到和超过预期要求.

The establishment of a high-precision optical link is a necessary condition for satellite-to-ground quantum communication experiments. Compared with conventional laser communications, a quantum experimental satellite needs to solve special requirements such as the great difference between the energy of quantum light and beacon light, and the establishment of optical links between one satellite and two ground stations. Based on the scientific demands of satellite-to-ground quantum communication, this paper proposes an overall scheme for an optical link establishing system with a combination of satellite pointing and load autonomous searching.By using a multiple-axis pointing control method, the requirements of high-precision optical tracking are met.We use the stare-stare capture method to achieve fast capture between the satellite and the ground stations.The high-precision alignment of the satellite and ground quantum beams is realized by using a method of joint scanning and system correction. Finally, in-orbit test results of the Mo-tse quantum experimental satellite are given. The experimental data show that all parameters in the establishment of optical links meet or exceed the expected requirements.