CV-QKD Design for Network Integration.

Continuous-variable quantum key distribution (CV-QKD) has reached a maturity that requires to consider its integrability into optical communication networks. As a key exchange, QKD cannot take the central role in optical network design but has to adapt to the requirements of the network.In this article compact CV-QKD prototypes, which have been demonstrated in operational environments, and several of their key features for facilitating network integration are presented. Among these features are the coverage of typical metro link losses with automatic adaptation to the channel conditions as well as in-channel synchronization, which reduces the spectral needs to a single dense-wavelength-division-multiplexing (DWDM) channel. In many situations, this fully C-band tunable channel can simply be connected to a free multiplexer port of an existing DWDM infrastructure. Any-to-any connectivity between many QKD transmitters and receivers can reduce the number of devices, while dynamic protocol switching allows to address different security requirements and cryptographic tasks.