Photonic Integrated Phase Encoding Transmitter for Satellite QKD

In 2017, the Micius mission [1] showed that satellite quantum key distribution (QKD) can surpass the range limit of fiber-based QKD [2]. Due to the high launch cost of satellites the cost of these systems would be reduced significantly if the size, weight and power of the satellites could be reduced. This requires the use of new integration technologies, like the miniaturized modules based on photonic integrated circuits (PIC) tested in the QUBE mission [3], [4]. Using the knowledge gained there, the QUBE-II mission aims to launch an 8U CubeSat <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(10\times 20\times 40\text{cm}^{3})$</tex> with the goal of performing QKD between the cubesat and an optical ground station [5].