Wide Angle Receivers for Long-Distance Free-Space QKD
The biggest challenge to overcome in long-distance QKD is optical loss. Current mission designs foresee separate optical telescopes, light sources and detectors for the quantum channel and the classical guiding beacon, which strains the stringent size and payload limitations any space mission is subject to. A new design is proposed, that combines quantum key detection and pointing-and-tracking hardware into a single receiver. The goal is to build up a quantum receiver for time-bin qubits with a large field of view, and that will provide spatial information for pointing and tracking directly from the quantum signal. This project reflects the growing interest in quantum communications in space.