Photonic Router: a 2-by-2 device that guides input photons to any one of the output ports with control signals.
Imagine the benefits if the entire internet got a game-changing upgrade to speed and security. This is the promise of the quantum internet - an advanced system that uses single photons (particles of light) to operate. Researchers at Tohoku University developed a new photonic router that can direct single and (quantum) entangled photons with unprecedented levels of efficiency. This advancement in quantum optics brings us closer to quantum networks and next-generation photonic quantum technologies becoming an everyday reality.
The findings were published in Advanced Quantum Technologies on September 2, 2025.
"It transmits photons with only 0.06 dB of loss, which is only about 1.3%," explains Kaneda, "Not only is it running efficiently at nanosecond speeds, it is already compatible with the telecommunication networks we use today for the internet. The findings from this research provide a valuable foundation for the development of practical quantum network technologies."
In a world-first demonstration, the team also successfully routed two-photon entangled statesーa crucial resource for quantum sensing and quantum networksーwhile maintaining interference visibility of about 97%. This shows that the router can handle not only individual quantum bits, but also complex multiphoton entanglementーa key requirement for scaling up quantum technologies.
Compared with previous approaches, which often suffered from high loss, noise, or distortion, this new device combines all the critical features needed for practical use: low loss, high speed, noise-free operation, and compatibility with existing telecom fiber networks.
