(Optics.org) Scientists in China have reported quantum key distribution (QKD) on a 50 kilometer-long commercial fiber network. The team, from Peking University and Beijing University of Posts and Telecommunications, say that they used a version of the encryption technology known as “continuous-variable” (CV) QKD, which uses standard fiber components, rather than specialist single-photon sources.
The main advantage of the approach is that the quantum keys can be distributed quickly, with no need for cooling of high-spec components. While the technique has been demonstrated in both the laboratory and deployed fiber networks before, this latest experiment is said to extend transmission distance and key distribution rates to new highs.