9 January 2020

By Donna Lu

The world’s first portable ground station for sending and receiving secure quantum communications is up and running. The station has successfully connected to China’s Quantum Space Satellite, nicknamed Mozi, which was launched in August 2016.

Ji-Gang Ren at the University of Science and Technology of China in Hefei and colleagues used the mobile station to send a secure data transmission from Jinan in north-eastern China.

Unlike the ground station used when Mozi launched, which weighed more than 10 tonnes, this mobile station weighs about 80 kilograms and is small enough to be installed the top of a car.

The significant downsizing comes with a slight reduction in transmitting power. The mobile ground station transmits data at a rate of between 4000 and 10,000 bits per second, compared to a rate of about 40,000 bits per second for larger stations, says Ren.

The team used the mobile ground station to perform quantum key distribution, a form of secure communication in which particles of light, called photons, are transmitted. It enables two parties to share a secret key that is used to encrypt and decrypt information.

A key was relayed via Mozi between the mobile ground station in Jinan and a fixed station in Shanghai.

Building a mobile quantum ground station was motivated by demand from users, such as the state-owned Industrial and Commercial Bank of China (ICBC), for equipment that didn’t require purpose-built infrastructure, says Ren.

ICBC and the People’s Bank of China are already using satellite-based quantum key distribution between distant cities, such as Beijing in northeast China and Ürümqi in the far northwest.

The team plans to launch a quantum nanosatellite in the next two years, targeted at commercial clients. “We want more and more users to use quantum keys to protect their important information,” says Ren.