Quantum Communication with Photonic Integrated Circuits on a CubeSat

Exponential losses limit the range of fiber based quantum key distribution (QKD) systems to several hundreds of kilometers [1]. In contrast, a satellite based QKD infrastructure could cover intercontinental distances and would enable world wide secure communication [2]. However, the profitability of a commercial system is highly dependent on its size, weight and power requirements. Photonic integration [3] is a well suited option as it allows the integration of all required optical components for a QKD system onto a single photonic integrated circuit (PIC). In this work, we present our CubeSat payload consisting of a PIC based sender for modulated weak coherent states as well as a quantum random number generator (QRNG). It was launched in 2024 as part of the QUBE mission [4], which aims for the demonstration of novel miniaturized building blocks for satellite quantum communication.