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.