Digital synchronization for continuous-variable quantum key distribution. (1st October 2022)

• Record Type: Journal Article
• Authors: Chin, Hou-Man; Jain, Nitin; Andersen, Ulrik L; Zibar, Darko; Gehring, Tobias
• Is Part Of: Quantum science and technology. Volume 7:Number 4(2022)
• Publication Date: 2022-10-01
• Subjects: continuous variable -- quantum key distribution -- digital signal processing -- synchronization; Quantum theory -- Periodicals; Quantum theory; Periodicals; 530
• DOI: 10.1088/2058-9565/ac7ba2
• Languages: English
• ISSNs: 2058-9565

Abstract

Abstract: Continuous variable quantum key distribution (CV-QKD) is a promising emerging technology for the distribution of secure keys for symmetric encryption. It can be readily implemented using commercial off-the-shelf optical telecommunications components. A key requirement of the CV-QKD receiver is the ability to measure the quantum states at the correct time instance and rate using the correct orthogonal observables, referred to as synchronization. We propose a digital synchronization procedure for a modern CV-QKD system with locally generated local oscillator for coherent reception. Our proposed method is modulation format independent allowing it to be used in a variety of CV-QKD systems. We experimentally investigate its performance with a Gaussian modulated CV-QKD system operating over a 10–20 km span of standard single mode fibre. Since the procedure does not require hardware modifications it paves the way for cost-effective QKD solutions that can adapt rapidly to changing environmental conditions.