Ciena has collaborated with REDIMadrid, the research network of Comunidad de Madrid, on an end-to-end quantum secure data transport project.

Using Ciena’s 6500 photonic line system, the project integrates a quantum channel with existing dense wavelength division multiplexing (DWDM) signals over the same fiber.

Carrying both classical and quantum signals in the form of quantum key distribution (QKD), co-propagation of the quantum channel on the C-band is made possible over one fiber instead of two. This is as DWDM enables dozens or even hundreds of separate light signals at different wavelengths through a single fiber strand, aided by programmable channel spacing. In addition, 400G and 800G can be supported per channel, with photonic layer intelligence removing any disruptions in the quantum channel.

Aside from supporting DWDM, Ciena’s 6500 system includes reconfigurable optical add-drop multiplexer (ROADM) technology, which the REDIMadrid team used to remotely administer wavelengths at different network nodes without touching the fiber.

REDIMadrid and EuroQCI

REDIMadrid aims to provide quantum-proof and secure communication solutions to Madrid’s research and higher education network, and is managed by IMDEA Software Institute, a research center supported by the Madrid Regional Government.

It forms part of the Madrid Quantum Communications Infrastructure (MadQCI), which aligns with the European Quantum Communication Infrastructure (EuroQCI) initiative.

Co-led in design by Deutsche Telekom, EuroQCI aims to develop a secure quantum communication infrastructure spanning the whole EU and its overseas territories, comprising a terrestrial segment relying on fiber communications networks linking strategic sites at both national and cross-border levels.

The scheme aims to develop a secure quantum communication infrastructure spanning the whole EU and its overseas territories, comprising a terrestrial segment relying on fiber communications networks linking strategic sites at both national and cross-border levels.

Pilot projects have included secure hospital-to-hospital transmission of medical data, encrypted communication between government institutions, and QKD links for critical infrastructure such as power grid control centers.

EuroQCI also aims to establish a quantum design facility and six quantum chips pilot lines, backed by up to €50 million in public funding.

The initiative is part of the European Commission's ambition plan to make Europe a global leader in quantum by 2030.

Recent continental quantum projects have seen Colt and Nokia collaborate with Honeywell in exploring quantum-safe networking using satellite communications.

Spain’s Telefónica has also recently worked on QKD links between Madrid hospitals as part of the European OPENQKD project, while Ericsson has been building a QKD network in Sweden since 2023.