Fast Single Photon Detectors and real-time Key Distillation: Enabling High Secret Key Rate QKD Systems

TL;DR

This paper introduces advanced superconducting nanowire single-photon detectors and real-time key distillation electronics, significantly boosting secret key rates in quantum key distribution over various distances.

Contribution

It presents a novel combination of high-speed detectors and electronics enabling over tenfold increase in secret key rates for QKD systems.

Findings

Achieved 64 Mbps secret key rate over 10 km

Reached 3.0 Mbps over 102.4 km

Enabled real-time key distillation with high-speed hardware

Abstract

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.