Coexistence of entanglement-based quantum channels with DWDM classical channels over hollow core fibre in a four node quantum communication network

TL;DR

This paper shows how quantum and classical communication can coexist in a fiber network, maintaining high performance over long distances.

Contribution

The novel contribution is demonstrating coexistence of entanglement-based quantum and classical channels in a multi-node network using hollow core fiber.

Findings

Three quantum channels coexist with 800 Gbps classical channels over 11.5 km hollow core fiber.

Quantum key distribution achieved Bell state fidelity of up to 90.0 ± 0.8%.

Secret key rates remained stable for 55 hours in a four-node quantum network.

Abstract

We experimentally demonstrate the coexistence of three entanglement-based quantum channels with carrier-grade classical optical channels over 11.5 km hollow core nested antiresonant nodeless fibre, in a four user quantum network. A transmission of 800 Gbps is achieved with four classical channels simultaneously with three quantum channels all operating in the C-band with a separation of 1.2 nm, with aggregated coexistence power of −3 dBm. We established quantum key distribution in the four-node full-mesh quantum network with Bell state fidelity of up to 90.0 ± 0.8%. The secret key rate for all the links in the network are passively preserved over 55 hours of experimental time.

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