Portugal has achieved a historic milestone in the field of quantum communication by successfully carrying out, for the first time, a secure quantum time transfer within the national territory. The project is part of the Portuguese Quantum Communications Infrastructure (PTQCI), Portugal’s segment of EuroQCI, the European Quantum Communication Infrastructure, which involves all 27 Member States of the European Union committed since June 2019 to its implementation.
The European Quantum Communication Infrastructure (EuroQCI) initiative aims to build a quantum communication infrastructure that spans the entire European Union, with the main goal of protecting sensitive data and critical infrastructures against cyberattacks. Since June 2019, the 27 EU Member States have signed the “Declaration on the European Quantum Communication Infrastructure”, demonstrating their commitment to this initiative.
In Portugal, the PTQCI represents the first terrestrial segment of EuroQCI, marking a fundamental step toward integrating the country into the future European quantum communications infrastructure.
As part of this project, the first secure quantum time transfer in Portuguese territory was carried out using QKD (Quantum Key Distribution) encryption technologies between the cities of Elvas and Portalegre, as well as between Elvas and the Spanish city of Badajoz, thus establishing the first cross-border connection of this kind.
The experiment involved the Quantum Photonics Laboratory (QuLab) of the Instituto de Telecomunicações - led by our researcher and Professor of Técnico Emmanuel Zambrini Cruzeiro and his team - along with Fundação para a Ciência e a Tecnologia (FCT) and Instituto Português da Qualidade (IPQ).
The demonstration took place between September 29 and 30, 2025, and was divided into two phases: In the first phase, the transfer occurred between Elvas and Portalegre, covering a distance of approximately 80 km; In the second, it was carried out between Elvas and Badajoz, over a 20 km distance, marking the first secure quantum time transfer between a Portuguese and a Spanish city.
This experiment demonstrated, in comparison with some existing commercial solutions, a clear advantage for time dissemination applications where security is essential, such as in the financial sector, military communications, and other critical infrastructures. The demonstration paves the way for time transfer over optical fibers, once quantum communication links become available, ensuring the highest possible levels of security.
More about QuLab:
The Quantum Photonics Laboratory (QuLab) is part of the Instituto de Telecomunicações (IT), an Associated Laboratory and Research and Development (R&D) Unit in the field of Information and Communication Technologies (ICT), as well as a Technology and Innovation Center (CTI).
Founded in 1992, the IT results from a partnership among several Portuguese universities and two companies, Altice Labs and Nokia, and currently has a team of more than 900 members, including integrated researchers, collaborators, PhD and master’s students, and research fellows.
QuLab focuses primarily on the research and development of optical and quantum technologies. The quantum technologies developed at the laboratory include quantum communication and cryptography systems, quantum computers, and quantum sensors.
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