Integrated high-performance error correction for continuous-variable quantum key distribution

TL;DR

This paper introduces a novel two-stage error correction method for continuous-variable quantum key distribution, significantly improving throughput, efficiency, and secure key rate, enabling practical high-rate quantum secure networks.

Contribution

A new two-stage error correction scheme suitable for integration with limited hardware resources, achieving record-breaking throughput and secure key rates in CV-QKD systems.

Findings

Error correction throughput improved over tenfold at FER<0.1.

Secure key rate increased by over 120% with the new method.

Real-time error correction achieved at over 500 Mbps.

Abstract

An integrated error-correction scheme with high throughput, low frame errors rate (FER) and high reconciliation efficiency under low signal to noise ratio (SNR) is one of the major bottlenecks to realize high-performance and low-cost continuous variable quantum key distribution (CV-QKD). To solve this long-standing problem, a novel two-stage error correction method with limited precision that is suitable for integration given limited on-chip hardware resource while maintaining excellent decoding performance is proposed, and experimentally verified on a commercial FPGA. Compared to state-of-art results, the error-correction throughput can be improved more than one order of magnitude given FER<0.1 based on the proposed method, where 544.03 Mbps and 393.33 Mbps real-time error correction is achieved for typical 0.2 and 0.1 code rate, respectively. Besides, compared with traditional decoding method, the secure key rate (SKR) for CV-QKD under composable security framework can be improved by 140.09% and 122.03% by using the proposed two-stage decoding method for codes rate 0.2 and 0.1, which can support 32.70 Mbps and 5.66 Mbps real-time SKR under typical transmission distances of 25 km and 50 km, correspondingly. The record-breaking results paves the way for large-scale deployment of high-rate integrated CV-QKD systems in metropolitan quantum secure network.