UAV "bridging" helps quantum communication Nanjing University achieve a major breakthrough

Xie Zhenda, Gong Yanxiao, etc. from Zhu shining team of Nanjing University have realized quantum entanglement distribution with the help of UAV as a mobile platform for the first time, which is a major breakthrough in the application of UAV in quantum communication. This achievement was recently published online in the National Science Review (NSR) under the title of "one based engagement distribution towards mobile quantum networks".
Quantum communication is a new type of communication which uses quantum effect to transmit information. Quantum entanglement distribution is one of the ways to achieve quantum communication, that is, to build a pair of entangled photons and send two photons to the two sides of the communication, even though they are separated by a certain distance, they also have what Einstein called "ghostly super distance effect". With this feature, information can be transmitted. This process can not be copied and cracked, and has the advantages of high security.
So what's the point of quantum entanglement distribution with UAV? Li Chi science and technology interviewed Professor Xie Zhenda of Nanjing University, the project leader.
Professor Xie said that this proves that the UAV, which is widely used now, can also become a node in the quantum communication network, with the characteristics of flexibility, rapid networking, good scalability and low cost.
At present, both optical fiber and satellite have successfully realized quantum entanglement distribution, which proves the reliability of these two communication channels. The team of Nanjing University explored a new way to build a "mobile quantum communication network" with UAV, and proposed a new scheme for the construction of quantum communication network.
After more than two years of efforts, the team members carried out and completed experiments in Nanjing, Shijiazhuang, Lanzhou and other places, which proved that the program has many advantages:
First of all, the equipment is very light.
High performance integrated quantum entangled light source. The light source weighs only 468g, which is one order of magnitude lighter than the entangled light source using traditional technology;
An integrated system of optical signal transmitting and receiving. The weight of the system is only 3.7kg. For the first time, the key quantum communication devices, such as entangled light source and free space single photon transceiver system, are highly integrated and lightweight. The reliable connection of optical link is realized, making it possible for UAV to carry quantum communication nodes;
The supporting portable ground station system is powered by lithium battery DC, which is less than 8kg. It can be folded and put into the satchel, and can be used when the machine is started.
Secondly, the system can effectively filter out the interference of sunlight on quantum signal - single photon in transmission, and can work normally in many weather conditions, such as day, night, rain and so on.
Third, at present, the team uses the multi rotor pure electric UAV as a platform, equipped with quantum communication equipment, with a endurance of dozens of minutes, which can meet some of the stringent requirements of quantum communication.
For this research result, the website of Scientific American once commented highly on Quantum Internet in a review article, saying that "the next best choice for quantum communication may be relatively cheap UAV".
Professor Xie said that in order to comply with the relevant regulations on UAV flight, the experiment is mainly carried out in low altitude airspace within 200m, and the effective distance of quantum communication is about 200m. However, the coverage of several square kilometers can be achieved by using the existing UAV capabilities through device parameter optimization and multi unit network.
This technology also has greater potential: if the quantum communication equipment they developed is carried by high altitude, long endurance UAV, high altitude balloon, etc., connected with the existing optical fiber and satellite quantum network, and solved the problem of all-weather and wide coverage of different levels of quantum network, it is of great significance to promote the practicality of quantum communication.
In addition, the UAV platform itself has a very strong mobility, which can be deployed in a low-cost and rapid emergency, temporarily establish a quantum communication link, and adapt to complex terrain, which is expected to be applied in national defense, disaster relief, finance and other fields.
It is understood that the research has been supported by the excellence program of Nanjing University, the national key R & D program of the Ministry of science and technology, the National Natural Science Foundation and other projects, as well as other cooperative units.