An entangled-LED driven quantum relay over 1 km

TL;DR

This paper demonstrates a quantum relay over 1 km of fiber using entangled photons from an LED, achieving high fidelity and surpassing classical limits, advancing secure quantum communication networks.

Contribution

It introduces a quantum relay using an entangled-LED source over 1 km fiber, showing high fidelity and potential for scalable quantum networks.

Findings

Relay fidelity of 0.90+/-0.03 exceeds classical bound of 0.75

Utilizes entangled photons emitted by a semiconductor LED

Source has low multi-photon emission, suitable for quantum networks

Abstract

Quantum cryptography allows confidential information to be communicated between two parties, with secrecy guaranteed by the laws of nature alone. However, upholding guaranteed secrecy over quantum communication networks poses a further challenge, as classical receive-and-resend routing nodes can only be used conditional of trust by the communicating parties. Here, we demonstrate the operation of a quantum relay over 1 km of optical fiber, which teleports a sequence of photonic quantum bits to a receiver by utilizing entangled photons emitted by a semiconductor LED. The average relay fidelity of the link is 0.90+/-0.03, exceeding the classical bound of 0.75 for the set of states used, and sufficiently high to allow error correction. The fundamentally low multi-photon emission statistics and the integration potential of the source present an appealing platform for future quantum networks.