Automatic Installation in QKD System

Wakako Meda, Akihiro Tanaka, Seigo Takahashi +1 more

M. Suda

A. R. Dixon, J. F. Dynes, Marco Lucamarini +11 more

Securing information in communication networks is an important challenge in today's world. Quantum Key Distribution (QKD) can provide unique capabilities towards achieving this security, allowing intrusions to be detected and information leakage avoided. We report here a record high bit rate prototype QKD system providing a total of 878 Gbit of secure key data over a 34 day period corresponding to a sustained key rate of around 300 kbit/s. The system was deployed over a standard 45 km link of an installed metropolitan telecommunication fibre network in central Tokyo. The prototype QKD system is compact, robust and automatically stabilised, enabling key distribution during diverse weather conditions. The security analysis includes an efficient protocol, finite key size effects and decoy states, with a quantified key failure probability of ε = 10⁻¹⁰.

Yuyang Ding, Hua Chen, Shuang Wang +6 more

Polarization variations in the installed fibers are complex and volatile, and would severely affect the performances of polarization-sensitive quantum key distribution (QKD) systems. Based on the recorded data about polarization variations of different installed fibers, we establish an analytical methodology to quantitatively evaluate the influence of polarization variations on polarization-sensitive QKD systems. Using the increased quantum bit error rate induced by polarization variations as a key criteria, we propose two parameters - polarization drift time and required tracking speed - to characterize polarization variations. For field buried and aerial fibers with different length, we quantitatively evaluate the influence of polarization variations, and also provide requirements and suggestions for polarization basis alignment modules of QKD systems deployed in different kind of fibers.

Daniel J. Rogers

Akihisa Tomita

Continuing efforts have been made to develop practical quantum key distribution (QKD) systems on the installed fiber networks since early 2000s [1]. Recently, several groups have demonstrated high-speed QKD systems [2,3] with GHz-clock frequency working stably on the installed-fiber networks [4-7]. Along with the hardware development, an efficient key management protocol [7] has been implemented to construct a QKD platform to supply information-theoretically secure key for multiple applications. The highly available QKD platform is expected to promote social deployment of the QKD technology.