The Micius satellite, launched from China in August 2016, is the first and only satellite dedicated entirely to quantum experiments. The ultralow loss transmission of photons on most of the path between ground and space enables quantum communication capabilities that are still far from being realized. This review details the commissioning of Micius as a full quantum communications system, and describes the achievement of global-scale quantum key distribution, entanglement distribution, and other fundamental studies, with this unique space-based system.
The Micius satellite, launched from China in August 2016, is the first and only satellite dedicated entirely to quantum experiments. The ultralow loss transmission of photons on most of the path between ground and space enables quantum communication capabilities that are still far from being realized. This review details the commissioning of Micius as a full quantum communications system, and describes the achievement of global-scale quantum key distribution, entanglement distribution, and other fundamental studies, with this unique space-based system.
The Micius satellite was successfully launched on 16 August 2016, from Jiuquan, China, orbiting at an altitude of about 500 km. The main scientific goals, including satellite-to-ground quantum key distribution, satellite-based quantum entanglement distribution, ground-to-satellite quantum teleportation, and satellite relayed intercontinental quantum network, were achieved in 2017. As a starting point, the Micius satellite has become a platform for quantum science experiments at the space scale. Here, we introduce the latest experimental achievements (in 2018-2020) based on the Micius satellite.
Quantum communication is proven to be the only unconditionally secure method for information exchange, which could well be the first commercial application of quantum information science. Compared with fiber-based demonstrations, free-space links could provide a more promising approach because photon loss and decoherence are almost negligible in the atmosphere. Furthermore, by using satellites, ultra-long-distance quantum communication and tests of quantum foundations could be achieved on a global scale. Here we report a serial of recent experimental progresses on free-space quantum communication over long distance in the Qinghai Lake area. In the meantime, besides the experimental efforts on the ground, Chinese Quantum Science Satellite has been launched on August 16th2016. And we will introduce the latest achievements in satellite-based quantum communication and large-scale tests of quantum foundations obtained through Micius.
By using satellites, ultra-long-distance quantum communication and tests of quantum foundations could be achieved at a global scale. The Quantum Experiment Science Satellite (QUESS) in China, also called Micius, one of the scientific satellite programs in the Strategic Priority Program on space science, the Chinese Academy of Sciences, was launched on 16 August 2016. There are totally 4 scientific payloads. We give a brief overview of the quantum experiment science satellite project and present most recent science results. The main scientific goal of the quantum experiment science satellite was achieved in 2017. Here, we introduce the latest achievements in satellite-based quantum communication and large-scale tests of quantum foundations obtained by Micius.
We perform decoy-state quantum key distribution between a low-Earth-orbit satellite and multiple ground stations located in Xinglong, Nanshan, and Graz, which establish satellite-to-ground secure keys with ∼kHz rate per passage of the satellite Micius over a ground station. The satellite thus establishes a secure key between itself and, say, Xinglong, and another key between itself and, say, Graz. Then, upon request from the ground command, Micius acts as a trusted relay. It performs bitwise exclusive or operations between the two keys and relays the result to one of the ground stations. That way, a secret key is created between China and Europe at locations separated by 7600 km on Earth. These keys are then used for intercontinental quantum-secured communication. This was, on the one hand, the transmission of images in a one-time pad configuration from China to Austria as well as from Austria to China. Also, a video conference was performed between the Austrian Academy of Sciences and the Chinese Academy of Sciences, which also included a 280 km optical ground connection between Xinglong and Beijing. Our work clearly confirms the Micius satellite as a robust platform for quantum key distribution with different ground stations on Earth, and points towards an efficient solution for an ultralong-distance global quantum network.
Satellite-based quantum communications represent a critical advancement in the pursuit of secure, global-scale quantum networks. Leveraging the principles of quantum mechanics, these systems offer unparalleled security through Quantum Key Distribution (QKD) and other quantum communication protocols. This review provides a comprehensive overview of the current state of satellite-based quantum communications, focusing on the evolution from terrestrial to space-based systems. We explore the distinct advantages and challenges of discrete-variable (DV) and continuous-variable (CV) quantum communication technologies in the context of satellite deployments. The paper also discusses key milestones such as the successful implementation of quantum communication via the Micius satellite and outlines the primary challenges, including atmospheric turbulence and the development of quantum repeaters, that must be addressed to achieve a global quantum internet. This review aims to consolidate recent advancements in the field, providing insights and perspectives on the future directions and potential innovations that will drive the continued evolution of satellite-based quantum communications.
Quantum key distribution (QKD) can in principle offer unconditional security by making use of the fundamental laws of quantum mechanics. In practice, this is typically achieved by preparing individual photons in quantum superposition states and sending them to a remote receiver. To date, most commercially available QKD systems rely on the transmission of the photons via optical fibers, which, due to channel loss and detector noise, limits the distance over which QKD is feasible to a few hundred kilometers. Alternatively, satellite-based QKD facilitates low photon loss and negligible signal disturbance and offers a viable solution for establishing a global scale quantum network. Recently, a quantum science mission of the Chinese Academy of Sciences (CAS) in collaboration with the Austrian Academy of Sciences (AAS) and the University of Vienna aimed at a satellite-based intercontinental quantum-key relay. Using the Chinese Quantum Science Satellite “Micius” as a trusted relay, a quantum network consisting of three optical ground stations located in China (Xinglong, Nanshan) and Austria (Graz-Lustbühel) has been demonstrated successfully. Here we report on the development of a quantum receiving module, installed at the Satellite Laser Ranging Station in Graz (Austria) capable of implementing the so-called decoy-state QKD protocol in a downlink scenario from the LEO satellite “Micius”. Furthermore, we will present the experimental results obtained during several downlinks from the Chinese satellite focusing on the performance of the Austrian receiving station.