A CubeSat platform for space based quantum key distribution

TL;DR

This paper discusses the development of a CubeSat platform capable of space-based quantum key distribution, demonstrating entangled photon generation in orbit and outlining the design of ground and space components for secure quantum communication.

Contribution

It presents a compact, cost-effective CubeSat system for satellite-based quantum key distribution, including the integration of a polarization-entangled photon source and ground station design.

Findings

Successful demonstration of entangled photon generation in orbit

Development of a functional demonstrator for quantum key distribution

Design of a ground station for quantum signal reception

Abstract

Satellite nodes are an enabler of global quantum networks by overcoming the distance limitations of fiber and free-space links on ground. The design of quantum sources and receivers for satellites, however, is challenging in terms of size, weight, and power consumption, as well as mechanical and thermal stability. This is all the more true for cost-efficient nanosatellites such as the popular CubeSat platform standard. Here we report on the follow-up mission of SpooQy-1, a 3U CubeSat that successfully demonstrated the generation of polarization-entangled photons in orbit. The next iteration of the mission will showcase satellite-to-ground quantum key distribution based on a compact source of polarization-entangled photon-pairs, and we have recently completed the integration of a fully functional demonstrator as a milestone towards the flight model. We also briefly describe the design of the optical ground station that we are currently building in Singapore for receiving the quantum signal. We present the most important subsystems and illustrate the concept of operation.