Nanowerk  November 1, 2021
A key element for achieving discrete-variable QKD is a single-photon detector. Researchers in China heterogeneously integrated, superconducting silicon-photonic chip. Harnessing the unique high-speed feature of the optical waveguide-integrated superconducting detector, they performed optimal Bell-state measurement (BSM) of time-bin encoded qubits generated from two independent lasers. The optimal BSM enables an increased key rate of measurement-device-independent QKD (MDI-QKD), which is immune to all attacks against the detection system and hence provides the basis for a QKD network with untrusted relays. Together with the time-multiplexed technique, they enhanced the sifted key rate by almost one order of magnitude. With a 125-MHz clock rate, they obtained a secure key rate of 6.166 kbps over 24.0 dB loss. Combined with integrated QKD transmitters, a scalable, chip-based, and cost-effective QKD network should become realizable soon…read more. Open Access TECHNICAL ARTICLEÂ
Schematic of a time-multiplexed MDI-QKD and a star-like MDI-QKD network… Credit: Advanced Photonics, 3(5), 055002 (2021).Â