Experimental entanglement generation for quantum key distribution beyond 1 Gbit/s

TL;DR

This paper introduces a high-performance entangled photon source at telecom wavelengths capable of generating secure quantum keys exceeding 1 Gbit/s, advancing practical quantum communication.

Contribution

The work presents the first entangled photon source that combines high pair-creation rate, broad bandwidth, high fidelity, and low loss for gigabit quantum key distribution.

Findings

Achieved secure key rates over 1 Gbit/s.

Demonstrated a wavelength-multiplexing approach for quantum networks.

Showcased compatibility with existing telecommunication infrastructure.

Abstract

Top-performance sources of photonic entanglement are an indispensable resource for many applications in quantum communication, most notably quantum key distribution. However, up to now, no source has been shown to simultaneously exhibit the high pair-creation rate, broad bandwidth, excellent state fidelity, and low intrinsic loss necessary for gigabit secure key rates. In this work, we present for the first time a source of polarization-entangled photon pairs at telecommunication wavelengths that covers all these needs of real-world quantum-cryptographic applications, thus enabling unprecedented quantum-secure key rates of more than 1 Gbit/s. Our source is designed to optimally exploit state-of-the-art telecommunication equipment and detection systems. Any technological improvement of the latter would result in an even higher rate without modification of the source. We discuss the used wavelength-multiplexing approach, including its potential for multi-user quantum networks and its fundamental limitations. Our source paves the way for high-speed quantum encryption approaching present-day internet bandwidth.