The world’s first quantum microsatellites demonstrate secure communication with multiple ground stations

The research team developed the world’s first quantum microsatellite, demonstrating real-time quantum key distribution (QKD) between satellites and multiple compact mobile ground stations.

The research led by USTC’s Pan Jianwei, Peng Chengzhi and Liao Shengkai has been published in collaboration with the Jinan Institute of Quantum Technology of Technical Physics Institute and the Innovation Academy of the Stellenbosch of Stouth Africa.

Quantum secure communication is the basis of national information security and socioeconomic development. A proven, unconditional security-enabled communication method, QKD greatly enhances data transmission security. Fiber-based QKD networks have achieved regional implementations, but practical applications over long distances remain constrained by signal loss and limited coverage. Satellite-based systems present viable solutions through free-space communications, potentially enabling QKD on a global scale.

USTC has pioneered groundbreaking research with satellite-based QKD. The launch of the Micius Quantum Satellite has achieved the world’s first successful demonstration of Space QKD. It was integrated with the fiber-based Beijing Shanggai backbone to create a space-ground quantum-safe communication network.

However, for practical applications, compact payloads and portable ground stations are essential for widespread deployment and rapid implementation. In particular, small-sized payloads can be assembled into satellites of various sizes to form quantum satellite Internet constellations for global services.

To achieve this, the team has developed several key technologies, including quantum state preparation, small decoy state QKD light sources for real-time key distillation and encrypted communication based on laser communication, and high-precision tracking based on satellite attitude control to maintain stable optical links.

Based on these advances, the team successfully launched the Jinan-1, the world’s first quantum microsatellite, on July 27, 2022. Additionally, the team developed a compact optical status, reducing it to less than double digits to less than 100 kg. This lightweight design allows for rapid deployment in a variety of locations, greatly increasing flexibility and practicality.

During the experiment, Zinan-1 established optical links with multiple optical ground stations in China’s Zinan, Hefei, Nanshan, Uhan, Beijing, Shanghai and Stellenbosch in South Africa. The satellite sent around 250 million quantum photons per second. For each satellite path, the system generated a secure key of up to 1 Mbits. Using the satellite as a reliable relay, the team successfully secured key sharing and encrypted communication between two cities separated by 12,900 km and Stellenbosch.

The team’s work lays a solid foundation for quantum microsatellite constellations deployment, provides critical technical support for large quantum communications networks, and holds immense promises for the global deployment of the quantum Internet.