Quantum Communications Uplink to a 3U CubeSat

Losses limit the maximum distance of ground based quantum communication to approximate to 400 km. Satellites overcome this limitation. Till date there have been numerous feasibility studies and two successful, large-scale quantum communications satellite missions. Achieving similar performance with a tiny, low-cost CubeSat in the uplink scenario is a major challenge. Here we present a feasibility study for a fully functional 3U-CubeSat-based quantum receiver. The advantage of this scheme is twofold: first, the majority of complex and critical equipment is ground based; second, one satellite design is compatible with a variety of quantum optical experiments. We provide a complete link loss analysis, count rate estimations and preliminary design. Further we discuss solutions to key problems such as satellite pointing errors and measurement/detection issues. Using current technology, we show that the CubeSat is feasible and can be used to violate a Bell-like inequality over a free-space distance of 500 km.