The quantum network makes use of quantum states to transmit data,which will revolutionize classical communication and allow for some breakthrough applications.Quantum key distribution(QKD)is one prominent application ...The quantum network makes use of quantum states to transmit data,which will revolutionize classical communication and allow for some breakthrough applications.Quantum key distribution(QKD)is one prominent application of quantum networks,and can protect data transmission through quantum mechanics.In this work,we propose an expandable and cost-effective quantum access network,in which the round-trip structure makes quantum states travel in a circle to carry information,and the multi-band technique is proposed to support multiuser access.Based on the round-trip multi-band quantum access network,we realize multi-user secure key sharing through the continuous-variable QKD(CV-QKD)protocol.Due to the encoding characteristics of CV-QKD,the quadrature components in different frequency bands can be used to transmit key information for different users.The feasibility of this scheme is confirmed by comprehensive noise analysis,and is verified by a proof-of-principle experiment.The results show that each user can achieve excess noise suppression and 600 bit/s level secure key generation under 30 km standard fiber transmission.Such networks have the ability of multi-user access theoretically and could be expanded by plugging in simple modules.Therefore,it paves the way for near-term largescale quantum secure networks.展开更多
基金Key R&D Program of Guangdong Province(2020B030304002)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)+1 种基金National Natural Science Foundation of China(61671287,61971276,62101320)National Key Research and Development Program of China(2016YFA0302600)。
文摘The quantum network makes use of quantum states to transmit data,which will revolutionize classical communication and allow for some breakthrough applications.Quantum key distribution(QKD)is one prominent application of quantum networks,and can protect data transmission through quantum mechanics.In this work,we propose an expandable and cost-effective quantum access network,in which the round-trip structure makes quantum states travel in a circle to carry information,and the multi-band technique is proposed to support multiuser access.Based on the round-trip multi-band quantum access network,we realize multi-user secure key sharing through the continuous-variable QKD(CV-QKD)protocol.Due to the encoding characteristics of CV-QKD,the quadrature components in different frequency bands can be used to transmit key information for different users.The feasibility of this scheme is confirmed by comprehensive noise analysis,and is verified by a proof-of-principle experiment.The results show that each user can achieve excess noise suppression and 600 bit/s level secure key generation under 30 km standard fiber transmission.Such networks have the ability of multi-user access theoretically and could be expanded by plugging in simple modules.Therefore,it paves the way for near-term largescale quantum secure networks.
