Toward Space Deployment of Polarization Entangled Photon Sources

Quantum entanglement represents a transformative resource for space-based infrastructure, enabling future global quantum communication, quantum computing networks, and distributed quantum sensing with unprecedented capabilities. Entanglement-based protocols such as quantum key distribution (QKD) enable information-theoretically secure links over global distances and represent a key near-term application of space-based quantum technologies.
In this paper, we present preliminary results from the development of miniaturized entangled photon source payload prototypes under the European research initiatives LaiQa and QuTechSpace. These payloads are engineered to meet the stringent size, weight, power, and environmental requirements of small satellite platforms. Our design prioritizes compact footprint, scalability, and robustness while preserving entanglement quality and photon‐pair generation efficiency suitable for space operation.
We report first laboratory performance measurements of the miniaturized sources, including photon-pair production rates, polarization correlation visibility, and heralding efficiency. Results indicate that scalable entangled photon generation with high brightness and entanglement fidelity is achievable in a form factor compatible with small satellite payload constraints.
These findings demonstrate the feasibility of deploying entanglement-based payloads on small satellites and provide key data supporting their readiness for upcoming space demonstrations. The work contributes to advancing payload innovation within the small satellite community by addressing real-world challenges in quantum payload miniaturization and performance benchmarking. The presented results highlight the potential of space-borne entanglement sources to enable secure communications and future quantum networking applications.