Researchers Develop Quantum Repeaters with All-Photonic Protocol for Quantum Network

(PhysicsWorld) A worldwide “quantum internet” could be one step closer thanks to researchers in Japan and Canada who have made the first ever quantum repeaters that work using an all-photonic protocol. Takashi Yamamoto of Osaka University and his colleagues are reporting on the first experimental demonstration for a key component of the all-photonic quantum repeater – the time-reversed adaptive Bell measurement. Their scheme is based on optical devices alone and does not require any quantum memories or quantum error correction.
Yamamoto explained, “In our experiment, we prepared entangled single photons in a repeater node and confirmed that the device only teleports lossless quantum information without being disturbed by surrounding lost quantum information. This is not only the first proof-of-principle demonstration of the adaptive Bell measurement but also a key principle of all-photonic quantum repeaters.”
The researchers say they now plan to develop large-scale graph-state photon generators and ultra-low loss photonic circuits that allow for the time-reversed adaptive Bell measurement on a large number of photons. “These circuits will enable us to scale up an all-optical quantum network,” says Yamamoto.