Quantum key distribution at GHz transmission rates
Alessandro Restelli, Joshua C. Bienfang, Alan Mink, Charles W. Clark · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2008
Quantum key distribution (QKD) channels are typically realized by transmitting and detecting single photons, and therefore suffer from dramatic reductions in throughput due to both channel loss and noise. These shortcomings can be mitigated by applying telecommunications clock-recovery techniques to maximize the bandwidth of the single-photon channel and minimize the system's exposure to noise. We demonstrate a QKD system operating continuously at a quantum-channel transmission rate of 1.25 GHz, with dedicated data-handling hardware and error-correction/privacy amplification. We discuss the design and performance of our system and highlight issues which limit our maximum transmission and key production rates.