Quantum light sources for space applications – SoLuQS

Today, information systems are one of the world's main resources. As accentuated by the Covid-19 crisis, our society relies on an ever-increasing need to process and communicate data, with significant repercussions on politics, defense, health, innovation, daily-life and the economy. The level of security remains a major issue for many use-cases, where secret key encryption are provably secure and can be implemented in the real world via quantum solutions.
Quantum-safe communication, the first commercially available quantum technology, provides a unique means to establish, between distant locations, random strings of identical secret bits, with a level of security unattainable using conventional approaches. The implementation of actual quantum systems has become crucial, given the strong military, societal and economic impacts. This path, considered as one of the most promising for IT innovation, benefits from largely endowed R&D programs, such as the EU Flagship and other national initiatives (UK, Germany, China, USA, France). With the development of quantum computers and sensors, it becomes of prime necessity to connect them. Consequently, tasks such as distributed quantum computing and sensing will lead to a large-scale quantum Internet. The major obstacle to the adoption of such networks lies in the limited distance (~100 km) over which they can be deployed, due to losses in optical fibers and the curvature of the Earth. In the absence of reliable quantum repeaters, the space segment represents the only potential way to circumvent this limitation. To date, the only real demonstrations have been made in China (Micius satellite), but many projects are underway at the international scale.
SoLuQS aims at effectively answering this demand by building industrial "entanglement source" prototypes that meet the constraints of spatialization, without compromising their performance. The key words of our achievements will be compactness and integrability, allowing satellite exploitation for both civil and military domains. These devices will eventually allow the connection of 2 metropolitan quantum networks (Paris and Nice). SoLuQS will therefore follow the promising path of new telecom-compatible laser optical communication systems in free space, and is thus part of the ASTRID AAP's thematic axis 3, "Cryptography - Communication", with a focus on "network security", their "operational implementation" based on "multimodal entanglement", as well as "space solutions". We will develop, at the French scale, the necessary tools for spatialization, in view of establishing a secure space/ground communication link, in order to anticipate future satellite realizations. SoLuQS brings together the best international teams in quantum communication (INPHYNI and LIP6) as well as a major French space industrial group (Thales Alenia Space) which will promote both integration and spatialization of the achievements.
The consortium will pursue an active knowledge dissemination strategy. IP and the attraction of industrialists have a directly exploitable economic value, both in terms of patents, market reach, and creation of start-ups. We will ensure the training of staff and students as well as the promotion of partners in both the academic and industrial communities. These activities will be complemented by dissemination actions (international conferences, scientific and general public publications, etc.) in order to maximize the project impact. Taken as a whole, our actions will ensure France to play a leading role on the international level, in terms of disruptive quantum technologies for space quantum communication.