Performance improvement of unidimensional continuous-variable quantum key distribution using heralded hybrid linear amplifier

• Published in: Physics letters. A 2020-01, Vol.384 (3), p.126074, Article 126074
• Main Authors: Zhou, Kunlin, Chen, Zhiya, Guo, Ying, Liao, Qin
• Format: Article
• Language: English
• Subjects: Continuous-variable quantum key distribution; Heralded hybrid linear amplifier; Unidimensional modulation
• ISSN: 0375-9601; 1873-2429
• DOI: 10.1016/j.physleta.2019.126074

We propose an improved scheme for unidimensional continuous-variable quantum key distribution (UCVQKD) using heralded hybrid linear amplifier, aiming to simplify the implementation and improve secret key rate. Different from the symmetrical continuous-variable quantum key distribution protocol (CVQKD), this scheme modulates one quadrature of the coherent state with security insurance. The heralded hybrid linear amplifier concatenates a deterministic linear amplifier (DLA) and a noiseless linear amplifier (NLA), which can tune between the high-gain or high noise-reduction for performance enhancement. Security analysis shows that the proposed scheme can be secured under the collective attacks. Compared with traditional UCVQKD involving noiseless amplifier, the security transmission distance of proposed protocol is increased by 24 kilometers. It not only simplifies the modulation process but also has approximate performance with symmetrical CVQKD in terms of maximal security transmission distance. •The method improves secret key rate of unidimensional modulation CVQKD.•The robustness against noise of unidimensional modulation CVQKD is improved.•The noise of unidimensional modulation CVQKD will decline when gDLA