Quantum key distribution (QKD) is among the most developed quantum technologies, promising information-theoretic security guaranteed by fundamental, quantum mechanical laws of nature. Since the invention of the celebrated BB84 QKD protocol three decades ago, this field has been growing steadily, as witnessed by the recent intercontinental QKD relay demonstration between China and Austria using a low-Earth-orbit satellite, as well as the 2000-km-long Beijing-Shanghai QKD link launched in 2017. Nevertheless, before QKD can be widely adopted, there are a number of important challenges to address. These include secure distribution of keys over long distances at high rates, integration of QKD networks with the existing infrastructure for data communications networks, providing easy access to end users at a low cost, and increasing immunity in practical settings. All these should come together in QKD services in future quantum communications networks. Such networks will then offer a platform for the deployment of other quantum communications technologies, beyond QKD applications, such as quantum digital signatures.
The purpose of this feature issue is to highlight the most recent theoretical and experimental developments in this field. Topic areas include, but are not limited to:
All papers need to present original, previously unpublished work, and will be subject to the normal standards and peer-review process of the journal. Manuscripts must be prepared according to the usual guidelines for submission to JOSA B and must be uploaded through OSA's electronic submission system. When submitting, please specify that the manuscript is for the Quantum Key Distribution and Beyond feature issue (choose from the drop-down menu).