Experimental wavelength-multiplexed entanglement-based quantum cryptography

TL;DR

This paper demonstrates a wavelength multiplexing technique leveraging entangled photons to significantly increase the secure key rate in quantum cryptography, applicable to fiber and satellite communication.

Contribution

It introduces a novel wavelength multiplexing approach that overcomes timing resolution limits in entanglement-based QKD, enabling higher key rates without modifying existing sources.

Findings

Key rate increases by several orders of magnitude

Technique applicable to fiber and satellite quantum communication

Compatible with most entanglement sources

Abstract

In state-of-the-art quantum key distribution (QKD) systems, the main limiting factor in increasing the key generation rate is the timing resolution in detecting photons. Here, we present and experimentally demonstrate a strategy to overcome this limitation, also for high-loss and long-distance implementations. We exploit the intrinsic wavelength correlations of entangled photons using wavelength multiplexing to generate a quantum secure key from polarization entanglement. The presented approach can be integrated into both fiber- and satellite-based quantum-communication schemes, without any changes to most types of entanglement sources. This technique features a huge scaling potential allowing to increase the secure key rate by several orders of magnitude as compared to non-multiplexed schemes.