Silicon photonics-based experimental daylight free-space quantum key distribution at telecom wavelength (Conference Presentation)

The future global-scale quantum communication network will require free-space and satellite links able to work in daylight conditions and compatible with the telecom fiber infrastructure. Here we present a full prototype for daylight quantum key distribution at 1550 nm exploiting an integrated silicon-photonics chip as state encoder. We tested our prototype in the urban area of Padua (Italy) over a 145m-long free-space link, obtaining a quantum bit error rate around 0.5% and an averaged secret key rate of 30 kbps. The developed chip represents a cost-effective solution for portable free-space transmitters and a promising resource for future satellite missions.