Emerging Imaging and Sensing Technologies for Security and Defence; and Advanced Manufacturing Technologies for Micro- and Nanosystems in Security and Defence
The Quantum Communications Hub is one of four Hubs comprising the research and development end of the UK National Quantum Technologies Programme. This programme is now in its second phase (2019-2024), following a successful first phase that ran 2014-2019. Our Hub provides the UK focus for the quantum communications sector. In this talk I'll provide a brief overview of the Hub's phase 1 developments, which mainly concentrated on progressing quantum key distribution (QKD) towards wider application. The grand vision of the phase 2 Hub is integrated secure quantum communications at all distance scales. For practicality and flexibility, this involves free-space communications at the shortest distance scales, fibre-based communications at the metrolpolitan and inter-city distance scales covered by current fibre networking, and free-space communications to support the very longest distances required for global reach. I'll outline the Hub activities on short-range consumer QKD, fibre networking and long distance satellite-to-ground QKD. I'll also cover our work on new protocols, hybrid secure communications, standards and components. http://www.quantumcommshub.net/
The Quantum Communications Hub is one of four Hubs comprising the research and development end of the UK National Quantum Technologies Programme. This programme is now in its second phase (2019-2024), following a successful first phase that ran 2014-2019. Our Hub provides the UK focus for the quantum communications sector. In this talk I'll provide a brief overview of the Hub's phase 1 developments, which mainly concentrated on progressing quantum key distribution (QKD) towards wider application. The grand vision of the phase 2 Hub is integrated secure quantum communications at all distance scales. For practicality and flexibility, this involves free-space communications at the shortest distance scales, fibre-based communications at the metrolpolitan and inter-city distance scales covered by current fibre networking, and free-space communications to support the very longest distances required for global reach. I'll outline the Hub activities on short-range consumer QKD, fibre networking and long distance satellite-to-ground QKD. I'll also cover our work on new protocols, hybrid secure communications, standards and components. http://www.quantumcommshub.net/
Quantum key distribution is now a mature quantum communication protocol which allows the verifiably secure sharing of encryption keys between two communicating parties. It seeks to address potential vulnerabilities of data transmission and storage, offering a realistic possibility to share encryption keys which are robust to eavesdropping attacks and future-proof against hacking. Fibre-optic implementations of quantum key distribution currently have a limited practical transmission distance, of less than 400 km, making commercial applications limited. Quantum-specific amplifier/repeater technology is not yet mature enough to increase the transmission distance to achieve global capabilities. Optical fiber is also impractical and expensive for applications where a remote area or moving platform are involved. In recent years, long-distance free-space quantum communications using low-Earth orbit satellites has seen an increase in interest from the academic community as well as from industrial organisations and national research institutes. The source of this new interest was a series of proof-of-principle demonstrations of satellite-based quantum key distribution in 2017. The use of free-space channels implementing airborne or satellite platforms also opens a range of new applications for quantum communications, as they allow coverage of remote areas, moving platforms, and also avoid the requirement of spooling fibre through volatile regions. This presentation will give a general introduction to satellite-based quantum communications, an overview of the field, and discuss future endeavours. The talk will also include an overview of our research into novel photonic technology, such as the use of detector array technology, for the optical ground station receiver.
Entanglement distribution is a fundamental building block of quantum communication networks, enabling the secure and reliable exchange of quantum information over long distances. Unlike classical communication, quantum networks exploit the unique properties of quantum entanglement to support applications such as quantum key distribution, quantum teleportation, distributed quantum computing, and networked quantum sensing. Although significant progress has been made in recent years, the efficient generation, transmission, and preservation of entangled states remain major research challenges due to photon loss, decoherence, and limitations in current communication infrastructure.This review provides a comprehensive overview of entanglement distribution in quantum communication networks, focusing on the technologies that enable practical implementation and the latest experimental developments. It discusses key approaches for generating and distributing entangled photons through optical fibers, free-space links, and satellite-based communication, together with supporting technologies such as quantum repeaters, quantum memories, and photonic devices. The review also examines recent experimental demonstrations that have advanced long-distance quantum communication while highlighting the technical barriers that must be overcome for large-scale deployment. Finally, emerging applications and future research directions are presented, including the development of scalable quantum networks, the quantum internet, and secure global communication systems. This review aims to provide researchers and students with a clear understanding of the current state of entanglement distribution and its growing role in next-generation quantum communication technologies.
Quantum communication promises to outperform its classical counterparts and enable protocols previously impossible. Specifically, quantum key distribution (QKD) allows a cryptographic key to be shared between distant parties with provable security. Much work has been performed on theoretical and experi- mental aspects of QKD, and the push is on to make it commercially viable and integrable with existing technologies. To this end I have performed simulations and experiments on QKD and other quantum protocols in regimes previously unexplored. \nThe first experiment involves QKD via distributed entanglement through the standard telecommunications optical fibre network. I show that entanglement is preserved, even when the photons used are a shorter wavelength than the design of the optical fibre calls for. This surprising result is then used to demonstrate QKD over installed optical fibre, even with co-propagating classical traffic. Because the quantum and classical signals are sufficiently separated in wavelength, little cross-talk is observed, leading to high compatibility between this type of QKD and existing telecommunications infrastructure. \nSecondly, I demonstrate the key components of fully-modulated decoy-state QKD over the highest-loss channel to date, using a novel photon source based on weak coherent (laser) pulses. This system has application in a satellite uplink of QKD, which would enable worldwide secure communication. The uplink allows the complex quantum source to be kept on the ground while only simple receivers are in space, but suffers from high link loss due to atmospheric turbulence, necessitating the use of specific photon detectors and highly tailored photon pulses. My results could be applied in a near term satellite mission.
Quantum Key Distribution (QKD) is currently the only known technique that is able to guarantee information-theoretic secure communications.While many countries have already started developing use-cases based mostly on terrestrial links, the high losses that afflict fiber-based channels make them unsuitable for very-long-distance communications.Taking the quantum networks to a national and global scale thus requires the use of satellite-based quantum communications, as the attenuation experienced by photons in space communications is order of magnitudes lower than the one that characterizes terrestrial networks.Thales Alenia Space in Italy (TAS-I) is positioning itself as a key actor in the development of the technology needed to perform space quantum communications.In this work, we present an overview of the initiatives that are currently being carried out by TAS-I, and define a roadmap whose steps are planned to take the current laboratory experimentation towards the development of a fully operational QKD constellation meant to provide secret keys on a global scale.We also describe a possible implementation of an Italian demonstrator mission based on a LEO satellite that acts as a trusted node to distribute shared keys among a certain number of ground stations; we study the effects of some major system choices and assess the overall achievable performance in terms of Secret Key Volume (SKV).
Long-distance quantum communication is one of the most important tasks in quantum information science. It contains two main motivations: one is the fundamental interests, and the other is the practical requirements. The physical distance of quantum communication over free-space channel has been extended from several meters in the lab to 1000 km through satellite. In this mini-review, we emphasize the progress made toward the global quantum network, mainly following the world’s first satellite-to-Earth quantum communication in 2017. This includes the development of commercial small-scale quantum satellite constellations and high-orbit satellites capable of all-time coverage, as well as the feasibility of quantum communication network. On this basis, we then discussed the possibility of cross-application of free-space quantum communication technology in fundamental physics, precision measurement, and even astronomical observations. Free-space quantum communication presents both challenges and opportunities, playing a crucial role in the future global quantum network.
Abstract - Quantum networking represents one of the most transformative developments in modern secure communication. Unlike classical networks that rely on mathematical encryption, quantum networks exploit the physical properties of qubits—superposition, entanglement, and the no-cloning theorem—to establish communication channels that are inherently tamper-evident. As quantum technologies mature, applications such as quantum key distribution (QKD), quantum repeaters, quantum teleportation, quantum memory systems, and quantum internet protocols are gaining global traction. This paper consolidates current progress in quantum networking technologies and provides an extended discussion of recent advancements in protocols, hardware components, integrated photonic systems, and machine-learning-enhanced architectures. Additionally, results synthesized from established literature, illustrate performance trends, security gains, and practical deployment challenges in quantum communication networks. The paper also outlines future directions toward scalable quantum internets, hybrid quantum-classical infrastructures, error-corrected qubit networks, satellite-based QKD, and intelligent routing systems. Overall, quantum networking is positioned to redefine the future of secure data transfer, distributed computing, and global communication infrastructures. Key Words: Quantum networking, Quantum Key Distribution (QKD), Entanglement Distribution, Integrated Photonic Chips, Machine Learning (ML)