Experimental Demonstration of High-Rate Discrete-Modulated Continuous-Variable Quantum Key Distribution System

TL;DR

This paper demonstrates a high-rate discrete-modulated continuous-variable quantum key distribution system capable of secure data transmission over tens of kilometers with high secret key rates, using advanced modulation and security techniques.

Contribution

It introduces a novel high-rate CV-QKD system with discrete modulation, achieving record secret key rates over various distances and demonstrating near-Gaussian performance.

Findings

Achieved secret key rates up to 288 Mbps over 5 km

Demonstrated comparable performance of DG 256QAM to ideal Gaussian modulation

Validated high-speed secure communication potential over tens of kilometers

Abstract

A high-rate continuous-variable quantum key distribution (CV-QKD) system based on high-order discrete modulation is experimentally investigated. With the help of the novel system scheme, effective digital signal processing algorithms and advanced analytical security proof method, the transmission results of 5 km, 10 km, 25 km, and 50 km are achieved for the 1 GBaud optimized quantum signals. Correspondingly, the asymptotic secret key rate (SKR) is 288.421 Mbps, 159.395 Mbps, 50.004 Mbps and 7.579 Mbps for discrete Gaussian (DG) 64QAM, and 326.708 Mbps, 179.348 Mbps, 50.623 Mbps and 9.212 Mbps for DG 256QAM. Under the same parameters, the achieved SKRs of DG 256QAM is almost same to ideal Gaussian modulation. In this case, the demonstrated high-rate discrete modulated CV-QKD system has the application potential for high speed security communication under tens of kilometers.