Ultra fast quantum key distribution over a 97 km installed telecom fiber with wavelength-division multiplexing clock synchronization

摘要

We demonstrated ultra fast BB84 quantum key distribution (QKD) transmissionat 625 MHz clock rate through a 97 km field-installed fiber using practicalclock synchronization based on wavelength-division multiplexing (WDM). Wesucceeded in over-one-hour stable key generation at a high sifted key rate of2.4 kbps and a low quantum bit error rate (QBER) of 2.9%. The asymptotic securekey rate was estimated to be 0.78-0.82 kbps from the transmission data with thedecoy method of average photon numbers 0, 0.15, and 0.4 photons/pulse.