Luca Mazzarella

We demonstrate fibre-based quantum key distribution over 175 km using a bright frequency converted quantum dot single-photon source. The source is capable of producing count rates approaching 2 MHz at 1550 nm with second order correlations on the order of 3%. This allows for a measured key rate of 130 bps (100 kbps) at 175 km (50 km) in the asymptotic regime using static encoding and predicted positive key rate out to 188 km. This can be extended to 240 km using ultra-low loss fibre based on the measured source parameters.

Space-based quantum key distribution (QKD) overcomes the limits of distance between terrestrial users caused by losses in optical fibre. Thus, it is the most promising method to establish a global scale QKD network. While the first QKD platform in the space - “the Micius satellite” – was a ground-breaking proof of principle demonstration, it is not a commercially favourable solution. We present our Cube-Sat payload design which has a more economically viable key-rate. The whole system is consisting of two parts, a 2U transmitter payload in Cube Satellite and an Optical Ground Station (OGS) working as receiver. The system is designed for polarisation based BB84/Decoy-State protocol with 100Mhz key transmission rate. In order to avoid the light pollution near the metropolitan centres and provide flexibility, we present our progress towards a mobile OGS which will be able to act as a receiver for the quantum signal.