China's first space high-speed coherent laser communication test will be carried out on quantum satellites

On August 16, the space high-speed coherent laser communication payload developed by the Shanghai Institute of Optics and Machinery of the Chinese Academy of Sciences was launched with a quantum satellite, and the high-speed coherent laser communication technology verification
between the satellite and the ground stations in Xinjiang and Beijing will be carried out.
This will be the first time that China has carried out a high-speed coherent laser communication test in space, marking that China has the initial ability
to develop inter-satellite coherent laser communication payloads.

Space high-speed laser communication technology is used to realize inter-satellite, satellite-ground high-speed data transmission, which can overcome the bottleneck of limited data transmission of high-resolution satellite imaging data, is an important means of space data relay and inter-satellite networking, and is also a cutting-edge high-tech technology
highly concerned by the aerospace community at home and abroad.

Chen Weibiao, director of the coherent laser communication payload of quantum satellites and deputy director of the Shanghai Institute of Optics and Mechanics of the Chinese Academy of Sciences, said that coherent detection laser communication has the technical advantages of high sensitivity and daytime work, and is especially suitable for high-speed laser communication
between satellites at ultra-long distances (tens of thousands of kilometers).
Compared with the first generation of direct detection laser communication technology with a rate of tens and hundreds of megabs per second, the second generation of space coherent laser communication technology can reach several gigabytes per second or even tens of thousands of megabs per second, becoming the mainstream scheme
of inter-satellite data relay at home and abroad.

Previously, developed countries such as Europe and the United States have invested a lot of manpower and material resources to carry out relevant technical research and made important progress
.
In 2007, the European Space Agency (ESA) was the first to achieve coherent laser communication
of 5.
6 Giga/s using multiplexing on the TerraSAR-X satellite and the US NFIRE satellite.
In 2015, ESA realized coherent laser communication between low-orbit and high-orbit satellites, with a communication distance of 50,000 kilometers and a communication rate of 1.
8 gigabit per second, opening a precedent
for data relay using coherent laser communication.

It is understood that in 2005, the Shanghai Institute of Optics and Mechanics of the Chinese Academy of Sciences began the research
of space coherent laser communication technology.
In 2012, with the support of the Chinese Academy of Sciences, the coherent laser communication on-orbit technology verification project
was launched.
Through more than 3 years of technical research, it has broken through a series of key technologies such as fiber lasers with spaceborne high-frequency frequency stability in the safe band of human eyes, high-speed coherent information coding modulation, high-sensitivity coherent reception, large-capacity real-time data processing, etc.
, and has completed the development of spaceborne coherent laser communication transmitting terminal and ground coherent laser communication receiving terminal, and single-channel communication has the communication capability
of satellite-ground rate of 5.
12 gigabit / second.