ITU Kaleidoscope Academic Conference (ITU K)
Differential phase shift quantum key distribution
Hiroki Takesue, Toshimori Honjo, Kiyoshi Tamaki, 康弘 都倉
Abstract
Quantum key distribution (QKD) has been studied as an ultimate method for secure communications, and it now is emerging as a technology that can be deployed in real fibre networks. Here, we present our QKD experiments based on the differential phase shift QKD (DPS-QKD) protocol. A DPS-QKD system has a simple configuration that is easy to implement with conventional optical communication components, and it is suitable for a high clock rate system. Moreover, although the DPS-QKD system is implemented with an attenuated laser source, it is inherently secure against strong eavesdropping attacks called photon number splitting attacks, which pose a serious threat to conventional QKD systems with attenuated laser sources. We also describe three types of single photon detectors that are suitable for high-speed, long-distance QKD: an upconversion detector, a superconducting single photon detector, and a sinusoidally gated InGaAs avalanche photodiode. We present our record setting QKD experiments that employed those detectors.