University of York Develops Compact Quantum Key Distribution Transmitter for CubeSats
Researchers at the University of York have successfully designed, built, and tested a continuous variable (CV) payload transmitter for downlink-based quantum key distribution (QKD) from a CubeSat. This development is part of the Satellite Platform for Optical Quantum Communications (SPOQC) mission by the Quantum Communications Hub, UK, which launched in March 2026. The CV-QKD scheme enables two parties to share a secret key over long distances, and this mission extends these capabilities to a cost-effective CubeSat platform. The system integrates both optical and electronic subsystems within a roughly ¾U CubeSat unit, adhering to strict size, weight, and power constraints. It employs amplitude and phase modulators to generate Gaussian modulated coherent states, a method for encoding information onto the quantum signal, and includes a quantum random number generator.
