Universidad Politécnica de Madrid and Q*Bird Launch Spain’s First Multi-Node MDI-QKD Network

The Universidad Politécnica de Madrid (UPM), in collaboration with Q*Bird, has officially deployed Spain’s first operational Measurement-Device-Independent Quantum Key Distribution (MDI-QKD) network. This multi-node infrastructure connects three distinct high-security sites: two locations within the Instituto Nacional de Técnica Aeroespacial (INTA) and one within the Ministry of the Interior (SGSICS). Unlike traditional point-to-point QKD, this deployment utilizes a hub-and-spoke topology that enables a fully connected mesh network without the need for "trusted nodes" at the central hub, a significant advancement for the security and scalability of metropolitan quantum communications.

The network is powered by Q*Bird’s Falqon® Series, featuring the MQX4000 center hub and the MQS4000 optical switch. This setup facilitates quantum key distribution over fiber distances ranging from 30 to 50 kilometers. By centralizing all measurement detectors at the hub—which itself never has access to the cryptographic keys—the MDI-QKD protocol effectively eliminates detector-based side-channel vulnerabilities. This architecture allows the UPM research team to evaluate critical performance metrics, such as key generation rates and loss tolerance, under realistic metropolitan conditions, serving as a blueprint for the broader EuroQCI initiative.

This deployment establishes Madrid as a primary hub for quantum innovation in Southern Europe and contributes to the continent's strategic autonomy in secure communications. Lead researcher Vicente Martín noted that the network provides a trusted foundation for digital sovereignty, ensuring that the data moving through the infrastructure remains secure even against future quantum-enabled threats. The successful integration into the Madrid Quantum Communication Infrastructure (MadQCI) validates that industrial-grade, scalable MDI-QKD is technically feasible for modern critical infrastructure and government environments.

Read the official press release from Q*Bird here and Quantum Delta NL here, and the project background from UPM here.

January 20, 2026