Continuous-Variable Quantum Key Distribution over 15 km Multi-Core Fiber

TL;DR

This paper demonstrates continuous-variable quantum key distribution over 15 km multi-core fiber, leveraging multiple cores to enhance secret key rates and showing promise for metropolitan quantum communication networks.

Contribution

It introduces the use of multi-core fiber for CV-QKD, enabling remote frequency locking and parallelization to boost key rates, advancing practical quantum communication.

Findings

Successful CV-QKD over 15 km multi-core fiber

Multi-core fiber enables parallel key distribution to increase rates

Remote frequency locking of local oscillator demonstrated

Abstract

The secure transfer of information is critical for the ever-increasing demands of the digital world. Continuous-variable quantum key distribution (CV-QKD) is a technology that can potentially provide information-theoretic security to cryptographic systems. CV-QKD is highly attractive thanks to high secret key rate generation over metropolitan distances and integration with the current classical communication networks. Here we demonstrate CV-QKD across a 15 km multi-core fiber (MCF) where we take advantage of one core to remotely frequency lock Bob's local oscillator with Alice's transmitter. We also demonstrate the capacity of the MCF to boost the secret key rate by parallelizing CV-QKD across multiple cores. Our results point out that MCFs are promising for metropolitan deployment of QKD systems.