基于优势提纯技术的片上量子密钥分发实验验证  

Experimental verification of on-chip quantum key distribution based on advantage distillation

作　　者：章瑞 田雨 张斌 陈高辉 丁华建 周星宇 王琴[2] ZHANG Rui;TIAN Yu;ZHANG Bin;CHEN Gaohui;DING Huajian;ZHOU Xingyu;WANG Qin(Changqing Oilfield Company Digital and Intelligent Business Division,China National Petroleum Corporation,Xi’an 710018,China;Institute of Quantum Information and Technology,Nanjing University of Posts and Telecommunications,Nanjing 210003,China)

机构地区：[1]中国石油长庆油田数字和智能化事业部,西安710018 [2]南京邮电大学,量子信息技术研究所,南京210003

出　　处：《物理学报》2025年第4期31-37,共7页Acta Physica Sinica

基　　金：江苏省重点研发计划产业前瞻与关键核心技术项目(批准号:BE2022071)资助的课题.

摘　　要：优势提纯提供了一种从弱关联性比特对中提取强关联性比特对的有效方法,已被广泛应用于多种量子密钥分发协议.然而,该方法的增益效果主要体现在远距离密钥传输中,目前在实验系统中尚未得到充分验证.本文将优势提纯方法应用于三强度诱骗态BB84协议,并基于SiO_(2)的非对称马赫-曾德尔干涉仪构建实验平台进行验证.SiO_(2)光波导芯片具有低耦合损耗和低波导传输损耗的优点.实验结果表明,在105 km的传输距离下,系统安全密钥率达到了59 bits/s,充分证明了优势提纯方法在提升量子密钥分发系统性能方面的重要作用.Quantum key distribution(QKD)has been extensively studied for practical applications.Advantage distillation(AD)represents a key technique to extract highly correlated bit pairs from weakly correlated ones,thus improving QKD protocol performance,particularly in large-error scenarios.However,its practical implementation remains under-explored.In this study,the AD is integrated into the three-intensity decoy-state BB84 protocol and its performance is demonstrated on a high-speed phase-encoding platform.The experimental system employs an asymmetric Mach-Zehnder interferometer(AMZI)fabricated on a silicon dioxide optical waveguide chip for phase encoding,which is benefited from its low coupling loss and minimum waveguide transmission loss.Phase-randomized weak coherent pulses,generated by a distributed feedback laser at 625 MHz,are modulated into decoy states of varying intensities.The signals are encoded via an AMZI and attenuated to single-photon levels before transmission.At the receiver,another AMZI demodulates the signals detected by avalanche photodiodes in gated mode.Experiments conducted at 50 km and 105 km demonstrate secure key rates of 104 kbits/s and 59 bits/s,respectively.The results at shorter distances closely match theoretical predictions,while slight deviations at 105 km are attributed to signal attenuation and noise.Despite these challenges,the results obtained at 105 km highlight the effectiveness of AD in enhancing secure key rates in the large-error scenario.This study confirms the potential of AD in extending secure communication range of QKD.By leveraging the high integration and scalability of silicon dioxide photonic chips,the proposed system lays a foundation for large-scale QKD deployment,paving the way for developing advanced protocols and realworld quantum networks.

关 键 词：量子密钥分发 优势提纯 光波导芯片 诱骗态 

分 类 号：TP3[自动化与计算机技术—计算机科学与技术]