10.5 km Fiber-Optic Quantum Key Distribution at 1550 nm with a Key Rate of 45 kHz

Abstract

High-speed single-photon detectors are crucial for efficiently performing quantum key distribution. We demonstrate fiber-optic quantum key distribution at 1550 nm using single-photon detectors operating at 10 MHz. Discharge pulse counting is adopted for single-photon detection in order to suppress after-pulse generation. Furthermore, by setting a dead time in single-photon detection, we discard after-pulses to reduce the number of bit errors in the quantum key distribution. Using discharge pulse counting and after-pulse discarding in the quantum key distribution, we can achieve a key rate of 45 kHz with a bit-error rate of 2%. The fiber length is 10.5 km.