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arXiv:2602.23510 · Optica Quantum

Continuous variable quantum key distribution channel emulator for the SPOQC mission

Emma Tien Hwai Medlock, Vinod N. Rao, Ry Render, Timothy Spiller, Rupesh Kumar

quant-phSubmitted Feb 26, 2026• Announced Mar 2, 2026• 0 citations
arXivHTMLPDF

Abstract

In a free space optical (FSO) communication link from satellite to ground, the losses in the channel will be dynamic. Thus, the characterization of the FSO channel is of great importance and this can be emulated in the lab to evaluate the realistic performance of a satellite payload. In this work, we introduce a novel optical channel emulator capable of replicating these dynamics, especially for Low Earth Orbit based CubeSats. We demonstrate its ability to accurately emulate a satellite-to-ground optical communications channel under various atmospheric turbulence strengths, satellite trajectories, and optical ground station parameters at a given optical wavelength of interest. Our satellite channel emulator was designed to test and benchmark the performance of the continuous variable quantum key distribution payload for the Satellite Platform for Optical Quantum Communications mission - an in-orbit demonstrator for the UK's Quantum Communication Hub, to be launched in early 2026.

Journal reference
Optica Quantum Vol. 4, Issue 1, pp. 73-81 (2026)
DOI
10.1364/OPTICAQ.578614
Comments
11 pages, 8 figures

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Real-time generation of quantum keys between satellite and ground nodes is essential for a scalable and global quantum network. We report the development of a QKD system that operate at gigahertz clock rate with multiplexed classical and quantum channels. This system is tested on a free-space link which is an emulation of the satellite to ground link with dynamic loss and random misalignments. With the assumption of a small satellite in low Earth orbit and a ground station with moderate aperture, we demonstrate the generation of >5 Mbits of quantum keys in a single emulated satellite pass.
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