A fast and versatile QKD system with hardware key distillation and wavelength multiplexing

Understand

We present a 625 MHz clocked coherent one-way quantum key distribution (QKD) system which continuously distributes secret keys over an optical fibre link.

• To support high secret key rates, we implemented a fast hardware key distillation engine which allows for key distillation rates up to 4 Mbps in real time.
• The system employs wavelength multiplexing in order to run over only a single optical fibre and is compactly integrated in 19-inch 2U racks.
• We optimized the system considering a security analysis that respects finite-key-size effects, authentication costs, and system errors.