A Survey on Continuous Variable Quantum Key Distribution for Secure Data Transmission: Toward the Future of Secured Quantum-Networks

TL;DR

This survey reviews the advancements in continuous-variable quantum key distribution (CV-QKD), highlighting its practical advantages, technological progress, and integration with modern optical networks for future secure quantum communication.

Contribution

It provides a comprehensive overview of CV-QKD, emphasizing recent technological innovations, integration strategies, and the application of machine learning and tensor networks to enhance system performance.

Findings

CV-QKD offers practical advantages over DV-QKD for current telecom infrastructure.

Machine learning techniques improve noise estimation and security in CV-QKD.

Photonic integrated circuits enable scalable CV-QKD system implementation.

Abstract

Quantum key distribution (QKD) represents a cornerstone of secure communication in the quantum era. While discrete-variable QKD (DV-QKD) protocols were historically the first to demonstrate secure key exchange, continuous-variable QKD (CV-QKD) has emerged as a more practical alternative due to its seamless compatibility with current telecommunications infrastructure. CV-QKD relies on coherent and squeezed states of light, offering significant advantages for integration into modern optical networks. This review comprehensively explores the theoretical underpinnings, technological advancements, and practical challenges of CV-QKD. Special attention is given to the role of photonic integrated circuits (PICs) in enabling scalable and efficient implementation of CV-QKD systems. Furthermore, recent advances in machine learning have been leveraged to optimize CV-QKD performance, with data-driven techniques enhancing noise estimation, parameter optimization, and system security. Additionally, tensor networks provide efficient computational tools for analyzing complex quantum correlations, improving the efficiency and robustness of quantum key distribution protocols. These developments, combined with ongoing improvements in quantum photonic integration, pave the way for the practical deployment of large-scale, high-speed quantum-secure networks.