多进制相干编码信号的双向高速空间激光通信研究

Free-space laser communications have the potential to be used in ocean voyage, emergency rescue, navigation, air transport, aerospace measurement and control, and other aspects due to their advantages of large transmission bandwidth, security, light weight, low power consumption, and small size. Compared to the direct detection, free-space laser communication systems based on coherent modulation and heterodyne (homodyne) detection have shown more advantages in transmission rate, sensitivity, resistance to atmospheric distortion and compensation. In particular, multi-level coherent modulated signals can be used to improve the spectrum efficiency of the optical carrier and hence increase the transmission bit rate. In this project, we plan to investigate high-speed and bidirectional free-space laser communications with multi-level coherent modulated signals. Bidirectional free-space laser communication will be realized with 20 Gb/s and beyond multi-level coherent modulation signals such as quadrature phase-shift keying (QPSK) and quadrature amplitude modulation (QAM) signals in kilometer-level distance. This project will be the first exploration of kilometer-level free-space laser communications with multi-level coherent modulated signals. It will provide practical technologies and valuable solutions for long-distance high-speed free-space laser communications, and do contributions to the future large-scale free-space communication applications in the field of military and civilian.

空间激光通信因其传输带宽大、安全性好、重量轻、功耗低、体积小等优点，在远洋航行、应急救援、导航定位、航空运输、航天测控等方面具有重要应用。和直接探测相比，基于相干调制/外差(零差)探测的空间激光通信在传输速率、灵敏度、抗大气干扰和补偿等方面更具优势，特别是通过多进制高阶编码可以有效提高频谱利用率，进一步增大传输速率。本项目拟研究多进制相干编码信号的高速双向空间激光通信，采用正交相移键控(QPSK)、正交振幅调制(QAM)等多进制高阶相干编码实验实现千米级别距离的20 Gb/s及以上高速双向空间激光信息传输。本项目将是在千米级别距离上对多进制相干编码空间激光信息传输的首次探索，将为中长距离高速空间激光通信提供实用技术和有价值的解决方案，为未来军事和民用领域的大规模空间通信应用做出贡献。

空间激光通信因其传输带宽大、安全性好、重量轻、功耗低、体积小等优点，在远洋航行、应急救援、导航定位、航空运输、航天测控等方面具有重要应用。和直接探测相比，基于相干调制/外差(零差)探测的空间激光通信在传输速率、灵敏度、抗大气干扰和补偿等方面更具优势，特别是通过多进制高阶编码可以有效提高频谱利用率，进一步增大传输速率。本项目研究了多进制相干编码信号的高速双向空间激光通信，采用正交相移键控(QPSK)多进制高阶相干编码，实验实现了1千米距离的20、30、40 Gb/s高速双向空间激光信息传输，分析了大气信道对信号传输质量的影响。结合波分复用技术，实验实现了速率高达120 Gb/s的1千米空间激光相干通信传输，结果表明相干编码和波分复用技术在空间激光通信中具有良好的兼容性。针对载荷受限的应用场合，基于半导体光放大器或者电光调制器提出了适用于高速传输的逆向调制反射(MRR)新方法，实现了20 Gb/s的逆向调制反射传输。提出并验证了基于单个光电探测器的多孔径相干接收系统，有望提高空间激光通信的接收灵敏度。本项目是在千米级别距离上对多进制相干编码空间激光信息传输的首次探索，将为中长距离高速空间激光通信提供重要的理论指导、实用技术和有价值的解决方案，为未来军事和民用领域的大规模空间通信应用做出贡献。