Tel Aviv University Demonstrates First Complete Quantum Encryption Key Transfer System
Researchers at Tel Aviv University's School of Physics and Astronomy have achieved a breakthrough in quantum communication by demonstrating the first complete system for Quantum Key Distribution (QKD) that seamlessly integrates optical fiber networks with free-space wireless communication without compromising quantum security. This advancement marks a significant step toward establishing global quantum communication networks that can connect terrestrial fiber optics with satellites, drones, and airborne platforms.
The study was led by doctoral students Chen Cohen and Tomer Nahum, alongside Michael Tsukran, Professors Yaron Oz and Haim Suchowski from Tel Aviv University, in collaboration with Professor Hagai Eisenberg from the Hebrew University and the HEQA Security company, which specializes in fiber-based quantum encryption. The researchers explained that quantum communication is considered the future of information security because it relies on quantum mechanics principles that detect any eavesdropping attempts.
Until now, a major challenge was bridging two different communication infrastructures: optical fibers, where information is encoded in photon arrival times, and free-space communication, which uses light polarization encoding. This gap hindered the development of extensive quantum networks. The new research introduced a unique optical interface that converts quantum information encoding between fiber optics and free-space communication bidirectionally without measuring or exposing the data, thus maintaining full quantum security.
The system was tested on the rooftops of Tel Aviv University, with wireless links spanning 90 and 750 meters under varying environmental conditions from hot afternoons to nighttime. The researchers continuously generated secure encryption keys even when atmospheric turbulence intensity varied by over two orders of magnitude, maintaining error rates well below accepted security thresholds.
Professor Yaron Oz emphasized the importance of this capability for the future "quantum internet," which will securely connect urban fiber networks with free-space links and eventually satellites. Such integration will enable unprecedentedly secure encrypted communication among users, institutions, and critical infrastructures, including governments, financial entities, and healthcare systems.
