Optics & Photonics News reports on Quantum Networks built on existing fiber-optic Infrastructure:
Researchers worldwide have made significant progress in building Quantum Networks in recent years. A key driver of this development is the rapid advances in Quantum Computing: powerful Quantum Computers could, in the future, threaten the security of today’s public-key cryptography, making new approaches to protecting sensitive data necessary. One possible solution is Quantum Key Distribution (QKD), which enables the secure exchange of cryptographic keys based on the principles of Quantum Mechanics. However, integrating such Quantum Technologies into existing optical communication and networking infrastructure remains technically challenging. At the same time, applications based on Quantum Entanglement, Quantum Teleportation, and entanglement swapping are increasingly coming into focus. Against this backdrop, the June issue of Optics & Photonics News features an article that traces the current state of integrating quantum and classical communication in fiber-optic networks, highlights recent advances, and offers an outlook on future perspectives.
The article first outlines the development of integrated quantum and classical communication systems – from early QKD demonstrations in the 1990s to current experiments in which Quantum Signals are transmitted alongside classical data traffic over existing fiber-optic networks. It becomes clear that while classical communication systems can cause interference for Quantum Signals, they also increasingly play a supporting role: they enable, for example, the synchronization, stabilization, and control of Quantum Networks. One example of this is so-called “Quantum Wrappers” – classical signal layers that provide routing and timing information without measuring the sensitive Quantum States themselves. The article also describes the shift from pure Quantum Key Distribution towards more complex network protocols: researchers have recently succeeded in experimentally demonstrating more sophisticated methods such as Quantum Teleportation and entanglement swapping under realistic conditions in fiber-optic environments. For instance, in 2026, researchers achieved the distribution of entangled photons over roughly 25 kilometers between Evanston and Chicago – while classical data traffic in the C‑band was running at full capacity. The joint transmission of Quantum Teleportation and classical data traffic also shows that key network functions are compatible with existing communication infrastructure.
The authors conclude that Quantum Networks are unlikely to emerge independently of existing communication systems; instead, close integration of quantum and classical communication will be crucial. Open questions particularly concern the development of high-performance Quantum Repeaters and the integration of distributed Quantum Computing into such coexistence architectures. However, the latest results show that important technical foundations for future Quantum Networks have already been experimentally demonstrated and are being continuously developed further. Click here for the article.
Quellennachweis: https://www.optica-opn.org/home/articles/volume_37/june_2026/features/building_quantum_networks_on_classical_fiber_infrastructure/