Quantum Key Distribution (QKD) is a cutting-edge communication method that enables secure communication between two parties. Continuous-variable QKD (CV-QKD) is a promising approach to QKD that has several advantages over traditional discrete-variable systems. Despite its potential, CV-QKD systems are highly sensitive to optical and electronic component impairments, which can significantly reduce the secret key rate. In this research, we address this challenge by modeling a CV-QKD system to simulate the impact of individual impairments on the secret key rate. The results show that laser frequency drifts and small imperfections in electro-optical devices such as the beam splitter and the balanced detector have a negative impact on the secret key rate. This provides valuable insights into strategies for optimizing the performance of CV-QKD systems and overcome limitations caused by component impairments. By offering a method to analyze them, the study enables the establishment of quality standards for the components of CV-QKD systems, driving the development of advanced technologies for secure communication in the future.
We would like to express our gratitude to Natalia Denisenko and Alfonso Blanco for their invaluable support and contributions to this research project. Their expertise and dedication greatly enhanced the quality of this publication.
This work had the support of Grant PID2020-118178RB-C22 funded by AEI/10.13039/501100011033, TED2021-130369B-C33 funded by MCIN/AEI/10.13039/501100011033 and by the European Union NextGenerationEU/PRTR, by the Community of Madrid (Spain) under the CYNAMON project (P2018/TCS-4566), co-financed with European Social Fund and EU FEDER funds. We also acknowledge the support of CSIC's Interdisciplinary Thematic Platform (PTI+) on Quantum Technologies (PTI-QTEP+). This study was supported by CSIC's program for the Spanish Recovery, Transformation and Resilience Plan funded by the Recovery and Resilience Facility of the European Union, established by the Regulation (EU) 2020/2094; and MCIN with funding from European Union NextGenerationEU (PRTR-C17.I1).