Ahmadi, NajmeNajmeAhmadiSchwertfeger, SvenSvenSchwertfegerWerner, PhilippPhilippWernerWiese, LukasLukasWieseLester, JosephJosephLesterRos, Elisa daElisa daRosKrause, JosefineJosefineKrauseRitter, SebastianSebastianRitterAbasifard, MostafaMostafaAbasifardCholsuk, ChanapromChanapromCholsukKrämer, Ria G.Ria G.KrämerAtzeni, SimoneSimoneAtzeniGündoğan, MustafaMustafaGündoğanSachidananda, SubashSubashSachidanandaPardo, DanielDanielPardoNolte, StefanStefanNolteLohrmann, AlexanderAlexanderLohrmannLing, AlexanderAlexanderLingBartholomäus, JulianJulianBartholomäusCorrielli, GiacomoGiacomoCorrielliKrutzik, MarkusMarkusKrutzikVogl, TobiasTobiasVogl2024-03-212024-03-212024https://publica.fraunhofer.de/handle/publica/46434610.1002/qute.2023003432-s2.0-85182826914Modern quantum technologies have matured such that they can now be used in space applications, e.g., long-distance quantum communication. Here, the design of a compact true single photon source is presented that can enhance the secure data rates in satellite-based quantum key distribution scenarios compared to conventional laser-based light sources. The quantum light source is a fluorescent color center in hexagonal boron nitride. The emitter is off-resonantly excited by a diode laser and directly coupled to an integrated photonic processor that routes the photons to different experiments performed directly on-chip: i) the characterization of the single photon source and ii) testing a fundamental postulate of quantum mechanics, namely the relation of the probability density and the wave function (known as Born's rule). The described payload is currently being integrated into a 3U CubeSat and scheduled to launch in 2024 into low Earth orbit. Therefore the feasibility of true single photon sources and reconfigurable photonic circuits in space can be evaluated. This provides a promising route toward a high-speed quantum network.enfundamental quantum sciencequantum key distributionsingle photonsspace quantum technologyjournal article