Free-space quantum key distribution

Abstract

Quantum key distribution (QKD) employs fundamental laws of quantum physics to distribute secret keys required for secure communications. Free-space QKD presents several advantages over fibre-optic systems, such as the possibility of implementing QKD between any two parties worldwide or the deployment of flexible and cheaper high-bit-rate secure links in metropolitan area networks. Some techniques and requirements for successfully implementing a free-space QKD system and the challenges of transmitting through the atmosphere will be discussed in this paper. © Sociedad Española de Óptica.