Multicore Fibers for Future Quantum Networks

Amid global uncertainties and evolving geopolitical tensions, ensuring the secrecy of critical communications and safeguarding European technological sovereignty has become paramount.

The vulnerabilities of traditional encryption methods have already been exposed and there are indications that certain countries are already employing the ""harvest now, decrypt later"" principle, emphasizing the urgency for enhanced digital security measures.

Quantum Key Distribution (QKD) offers a revolutionary approach to secure key exchange, harnessing the principles of quantum mechanics to provide perfect secrecy.

However, the widespread adoption of QKD still faces significant obstacles, including compatibility issues with existing telecom infrastructure and the current low secure key rates (SKR).Recent manufacturing advancements in multicore fibers (MCF) place them as a compelling answer, as they offer a host of advantages.

For instance, they provide support for spatial-division multiplexing, enabling to reach the SKR capacity demands; they facilitate the integration of quantum and classical networks within a single fiber with a smaller footprint compared to bundles of standard optical fibers; and they enable the distribution of entangled photons, opening the door for multiparty communication.

With these capabilities, MCFs assume a pivotal role in constructing the foundation of the future quantum network.This research explores the potential of MCF for next-generation quantum networks.

It aims to introduce and implement a novel space- and wavelength-division multiplexing scheme for high-dimensional (HD) QKD, offering an increased channel capacity and enhanced security.

Further, this project studies the distribution of entangled photons over a deployed MCF link and seeks to perform QKD between multiple users. Additionally, it aims to explore the coexistence of quantum information along with real-valued internet traffic.