Implementation of a high-speed quantum key distribution system for metropolitan networks

Improvement of QKD performance, particularly on key generation rate, has been required to meet current network traffic. A high-speed QKD system should be equipped with low loss receivers with high visibility, highly efficient photon detectors with small dark count probability, and a stable clock synchronization system with low stray light to the quantum signals, because the key generation rate is determined by photon detection rate and error rate. High speed post processing is also required to improve key generation through-put. A solution for these issues will be discussed.