On November 11, 2025, the Ruđer Bošković Institute (RBI) in Zagreb hosted the first public demonstration of functional quantum communication building blocks designed, developed, and integrated entirely in Croatia under the CroQCI project. According to RBI, the demonstrated systems included quantum receivers with optical modules and superconducting photon detectors, a quantum operator system generating entangled photon pairs, and FPGA-based encryptors developed by industrial partner OIV that secure messages using quantum-generated keys.
OIV reported that it had implemented the optical fiber infrastructure linking key institutions in Zagreb, which it called a prerequisite for the national quantum communication network. The QKD systems were already operating on OIV’s optical fiber network in Zagreb at the time of the demonstration.
RBI Director Dr. David M. Smith stated the technology built on prior international work, including an entanglement-based quantum communication network in Bristol in 2019 and the Italy-Slovenia-Croatia demonstration at the 2021 G20 summit. The CroQCI project, valued at €9.9 million, is co-funded by the EU Digital Europe Programme and Croatia’s National Recovery and Resilience Plan and runs through June 30, 2026.