Xinhua News Agency, Hefei, January 7th (Reporters Xu Haitao and Liu Fangqiang) 32 years ago, the first quantum communication in human history was born in a laboratory, which transmitted 32 cm.
Today, the Chinese have expanded this distance by more than 14 million times, realizing multi-user communication from the ground to the space.
The University of Science and Technology of China announced on the 7th that the Chinese scientific research team has successfully realized the satellite-to-earth quantum key distribution spanning 4,600 kilometers, marking that my country has constructed the prototype of a world-earth integrated wide-area quantum communication network.
The results have been published in the British "Nature" magazine.
Quantum communication is one of the three major directions of quantum technology. After more than 20 years of hard work, China has achieved a major change from a follow-up to a leader in this field.
In 2016, China successfully launched the world's first quantum science experimental satellite "Mozi"; in 2017, the world's first quantum secure communication trunk line "Beijing-Shanghai trunk line" was built.
"Mozi" has joined hands with the "Beijing-Shanghai Mainline". The University of Science and Technology of China Pan Jianwei, Chen Yuao, Peng Chengzhi and others cooperated with Wang Jianyu Research Group of Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Jinan Institute of Quantum Technology and China Cable Network Co., Ltd. The world's first satellite-to-earth quantum communication network.
After more than two years of stability and security testing, a multi-user quantum key distribution spanning 4,600 kilometers has been realized.
"To achieve wide-area quantum communication, there are a series of technical problems such as photon loss and decoherence. For example, the number of photons in the optical fiber will be lost for every 15 kilometers, and after 200 kilometers, only one ten thousandth is left." Pan Jianwei said, The scientific research team has developed a number of advanced technologies in optical systems and other aspects to resolve these problems.
According to Pan Jianwei, the reviewers of Nature said that this is the largest and most advanced quantum key distribution network on the planet, and it is a "huge engineering achievement" for quantum communication.
It is understood that the entire network covers 32 nodes in my country’s four provinces and three cities, including four quantum metropolitan area networks in Beijing, Jinan, Hefei and Shanghai. They are connected to the "Mozi" through two satellite ground stations, with a total distance of 4,600 kilometers. More than 150 users in the finance, power, government and other industries have been accessed.
Based on quantum characteristics such as "indivisible" and "non-clonal", quantum communication is called a "unconditionally secure in principle" communication method, which has application prospects in many fields.
The establishment of the satellite-to-earth quantum communication network lays the scientific and technological foundation for the realization of a global-covering "quantum network" in the future, and also provides an unprecedented "world laboratory" for scientific research such as relativity and gravitational waves.