Source-linked AI summary
Fast Single Photon Detectors and real-time Key Distillation: Enabling High Secret Key Rate QKD Systems
Fadri Grünenfelder, Alberto Boaron, Matthieu Perrenoud, Giovanni V. Resta, Davide Rusca, Claudio Barreiro, Raphaël Houlmann, Rebecka Sax, Lorenzo Stasi, Sylvain El-Khoury, Esther Hänggi, Nico Bosshard, Félix Bussières, Hugo Zbinden
TL;DR
Quantum key distribution secret key rates remain limited while demanding applications require substantially higher rates. This paper combines high-rate photon detection, fast electronics, and a 2.5 GHz time-bin QKD system to demonstrate real-time key distillation at 64 Mbps over 10.0 km and 3.0 Mbps over 102.4 km.
Problem
QKD systems need higher secret key rates, requiring high-rate detection, electronics processing, and real-time post-processing.
Method
The authors combine a custom high-count-rate, high-efficiency multipixel SNSPD and readout electronics with a simplified one-decoy BB84 system clocked at 2.5 GHz.
Results
64 Mbps over 10.0 km and 3.0 Mbps over 102.4 km were achieved with secret-key exchange and real-time key distillation.
Takeaways & Limitations
The demonstrated rates support secret-key-demanding applications such as real-time one-time-pad-secured video encryption in metropolitan areas.
Takeaways & Limitations
The LDPC error-correction implementation leaks 17% of the sifted key rate at 0.5% QBER, versus a 5% Shannon limit.
Abstract
from arXiv · showhide
Quantum Key Distribution has made continuous progress over the last 20 years and is now commercially available. However, the secret key rates (SKR) are still limited to a few Mbps. Here, we present a custom multipixel superconducting nanowire single-photon detectors and fast acquisition and real-time key distillation electronics, removing two roadblocks and allowing an increase of the SKR of more than an order of magnitude. In combination with a simple 2.5 GHz clocked time-bin quantum key distribution system, we can generate secret keys at a rate of 64 Mbps over a distance of 10.0 km and at a rate of 3.0 Mbps over a distance of 102.4 km with real-time key distillation.