Free-space multi-user quantum network with high key rate
- URL: http://arxiv.org/abs/2511.00466v2
- Date: Tue, 04 Nov 2025 06:37:34 GMT
- Title: Free-space multi-user quantum network with high key rate
- Authors: Ayan Kumar Nai, G. K. Samanta,
- Abstract summary: We demonstrate a free-space quantum space division multiplexing architecture using just one entanglement source.<n>The network achieves record coincidence rates exceeding $3 times 104$ s$-1$ between any pair of nodes on the network.
- Score: 0.0
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: Emergent quantum networks are the essential ingredient for securely connecting multiple users worldwide, extensively deployed in both fibre and free-space. An essential element is the multiplexing of entanglement to multiple users, overcoming the peer-to-peer restriction of quantum key distribution (QKD), so far successfully shown in fibre-based architectures. Here, we demonstrate a free-space quantum space division multiplexing architecture using just one entanglement source to realise a fully connected twelve-channel quantum network for seamless QKD connections between six users. The network achieves record coincidence rates exceeding $3 \times 10^{4}$ s$^{-1}$ between any pair of nodes on the network, for sifted key rate of over 400 kbps. Our approach overcomes the active switching hurdle that has hindered the free-space deployment of quantum multiplexing, is fully passive, easily scalable to more nodes and compatible with fibre-based integration, thus opening a new path to scalable and resource-efficient quantum networks that utilise free-space links.
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