The Hub’s Optical Ground Station (HOGS) is a strategic research facility designed to outlive the Hub’s SPOQC mission and continue to be used by researchers doing similar R&D work in the UK and in collaboration with international missions. The telescope has capability for two separate optical outputs, providing excellent scope for parallel UK and international collaborative projects, involving different satellites.

One such collaborative partnership is through the Hub’s Heriot-Watt research team and that of the QEYSSat mission, led by the Canadian Space Agency and supported by researchers at the University of Waterloo, Canada. QEYSSat (Quantum EncrYption and Science Satellite) is a low-earth orbit satellite with a quantum receiver and transmitter, capable of exchanging quantum-encoded photons with a quantum ground station via a line-of-sight freespace link. A unique feature of QEYSSat, when compared to other quantum satellites, is having the main quantum receiver on the satellite. Putting sensitive detectors in space has challenges, but this enables photonic uplinks in addition to downlinks, which allows testing of how new quantum sources on the ground could improve the uplink quality. There is also the potential for linking directly to terrestrial fibre-based quantum networks, using entangled photon pairs generated on the ground.

Through partnership resource, the Hub has funded a small project to allow connections from UK-based ground stations to QEYSSat, using such a new high-rate entangled photon source, developed by the Heriot-Watt team. The research teams on both sides of the Atlantic will exploit QEYSSat’s uplink feature and develop quantum sources capable of distributing one of a pair of entangled photons from the ground to satellite, simultaneously feeding the entangled partner photon into a terrestrial fibre network.