  The field of quantum information processing offers secure communication
protected by the laws of quantum mechanics and is on the verge of finding wider
application for information transfer of sensitive data. To overcome the
obstacle of inadequate cost-efficiency, extensive research is being done on the
many components required for high data throughput using quantum key
distribution (QKD). Aiming for an application-oriented solution, we report on
the realization of a multichannel QKD system for plug-and-play high-bandwidth
secure communication at telecom wavelength. For this purpose, a rack-sized
multichannel superconducting nanowire single photon detector (SNSPD) system, as
well as a highly parallelized time-correlated single photon counting (TCSPC)
unit have been developed and linked to an FPGA-controlled QKD evaluation setup
allowing for continuous operation and achieving high secret key rates using a
coherent-one-way protocol.
