Improvement of two-way continuous-variable quantum key distribution using optical amplifiers

TL;DR

This paper proposes adding a parameter-adjustable optical amplifier at the receiver in two-way continuous-variable quantum key distribution to enhance performance, approaching that of perfect detectors under certain noise conditions.

Contribution

The study introduces a novel method of using optical amplifiers to mitigate detector imperfections in two-way CV-QKD protocols, with a security analysis and simulation validation.

Findings

Performance improves with amplifier noise below a critical threshold

Optimal performance nears that of perfect detectors

Method enhances practical CV-QKD implementations

Abstract

The imperfections of a receiver's detector affect the performance of two-way continuous-variable quantum key distribution protocols and are difficult to adjust in practical situations. We propose a method to improve the performance of two-way continuous-variable quantum key distribution by adding a parameter-adjustable optical amplifier at the receiver. A security analysis is derived against a two-mode collective entangling cloner attack. Our simulations show that the proposed method can improve the performance of protocols as long as the inherent noise of the amplifier is lower than a critical value, defined as the tolerable amplifier noise. Furthermore, the optimal performance can approach the scenario where a perfect detector is used.