05 September 2024
The Paris Region Quantum Communication Infrastructure (QCI) consortium has implemented its first quantum communication network in existing fibre infrastructure.
Equipment related to quantum communications is expensive. To secure a link of less than 100km on a dedicated fibre, it takes approximately €180,000-250,000 just for a quantum key distribution (QKD) system. Accordingly, as part of the project, the consortium started with fibres already deployed by Orange France, some active and others dark.
The partners carried out measurements of optical losses by sending packets of photons into the fibre and characterising their round trips. Then they deployed a quantum communication system, developed by ID Quantique (IDQ), defined a ‘seamless’ network architecture, added a service layer, and implemented an encryption system that Thales adapted.
Quantum Key Distribution (QKD) was implemented on the infrastructure backbone with relays secured by post-quantum cryptography (PQC) to cover an extended distance range in Orange’s fibre network. The solution combines IDQ’s commercial Cerberis XG QKD system with embedded Clarion KX software suite (Key Management System), CryptoNext’s Quantum Safe Library (C-QSL) and classical symmetric cryptography.
PQC is the next generation of public key cryptography designed to be resistant to quantum computer attacks. In this setup, QKD provides unbreakable key exchange between remote encryption systems, while PQC guarantees relays security in large scale QKD network deployment.
The quantum fibre network has a range of around 80km. It interconnects several quantum nodes which are represented by the project partners, from the Saclay plateau (Thales, Institut d’Optique, Télécom Paris) to the LIP6 Sorbonne Université laboratory in the center of Paris, via the Orange Gardens site in Châtillon.
The consortium has demonstrated that for the application of a QKD technology, using or reusing already deployed commercial fibre infrastructures is possible. This represents a huge step forward in the realisation of secure quantum communications – for both wired and wireless applications.
