Quantum key distribution(QKD)is a secure communication method for sharing symmetric cryptographic keys based on the principles of quantum physics.Its integration into the fiber-optic network infrastructure is importan...Quantum key distribution(QKD)is a secure communication method for sharing symmetric cryptographic keys based on the principles of quantum physics.Its integration into the fiber-optic network infrastructure is important for ensuring privacy in optical communications.Multi-core fibers(MCFs),the likely building blocks of future high-capacity optical networks,offer new opportunities for such integration.Here,we experimentally demonstrate,for the first time,the coexistence of discrete-variable QKD and high-throughput classical communication in the C-band over a fielddeployed MCF with industry standard cladding diameter of 125μm.Specifically,we demonstrate successful secure-key establishment in one core of a 25.2-km uncoupled-core MCF,while simultaneously loading the remaining three cores with full C-band counter-propagating classical traffic at an aggregate net rate of 110.8 Tb/s.By proposing and experimentally validating an improved analytical model for inter-core spontaneous Raman scattering noise,we find that this configuration is optimal for our deployed MCF link as it is immune to four-wave mixing,that becomes relevant when the quantum and classical signals are propagating in the same direction.Our findings make an important step forward in demonstrating the integration of QKD and classical transmission in uncoupled-core multicore fibers for next-generation optical communication networks.展开更多
Multicore fibers are expected to be a game-changer in the coming decades thanks to their intrinsic properties,allowing a larger transmission bandwidth and a lower footprint in optical communications.In addition,multic...Multicore fibers are expected to be a game-changer in the coming decades thanks to their intrinsic properties,allowing a larger transmission bandwidth and a lower footprint in optical communications.In addition,multicore fibers have recently been explored for quantum communication,attesting to their uniqueness in transporting high-dimensional quantum states.However,investigations and experiments reported in literature have been carried out in research laboratories,typically making use of short fiber links in controlled environments.Thus,the possibility of using long-distance multicore fibers for quantum applications is still to be proven.We characterize here for the first time,to the best of our knowledge,in terms of phase stability,multiple strands of a four-core multicore fiber installed underground in the city of L’Aquila,with an overall fiber length up to about 25 km.In this preliminary study,we investigate the possibility of using such an infrastructure to implement quantumenhanced schemes,such as high-dimensional quantum key distribution,quantum-based environmental sensors,and more,in general,quantum communication protocols.展开更多
基金funded by the European Commission through European Union—Next Generation EU,under the Italian National Recovery and Resilience Plan,Mission 4,Component 2,Investment 1.3,CUP B53C22003970001,partnership on“Telecommunications of the Future”(PE00000001—program“RESTART”)in the Digital Europe Program under project QUID(Quantum Italy Deployment)Grant Agreement 101091408funding from the European Commission through ERC StG,QOMUNE,Grant Agreement 101077917.
文摘Quantum key distribution(QKD)is a secure communication method for sharing symmetric cryptographic keys based on the principles of quantum physics.Its integration into the fiber-optic network infrastructure is important for ensuring privacy in optical communications.Multi-core fibers(MCFs),the likely building blocks of future high-capacity optical networks,offer new opportunities for such integration.Here,we experimentally demonstrate,for the first time,the coexistence of discrete-variable QKD and high-throughput classical communication in the C-band over a fielddeployed MCF with industry standard cladding diameter of 125μm.Specifically,we demonstrate successful secure-key establishment in one core of a 25.2-km uncoupled-core MCF,while simultaneously loading the remaining three cores with full C-band counter-propagating classical traffic at an aggregate net rate of 110.8 Tb/s.By proposing and experimentally validating an improved analytical model for inter-core spontaneous Raman scattering noise,we find that this configuration is optimal for our deployed MCF link as it is immune to four-wave mixing,that becomes relevant when the quantum and classical signals are propagating in the same direction.Our findings make an important step forward in demonstrating the integration of QKD and classical transmission in uncoupled-core multicore fibers for next-generation optical communication networks.
基金orizon 2020 Framework Programme OpenQKD(857156),SQUARE(731473)Ministero dell’Istruzione,dell’Universitàe della Ricerca(INCIPIT)+1 种基金H2020 Science with and for Society(G5485)Danmarks Grundforskningsfond SPOC(123).
文摘Multicore fibers are expected to be a game-changer in the coming decades thanks to their intrinsic properties,allowing a larger transmission bandwidth and a lower footprint in optical communications.In addition,multicore fibers have recently been explored for quantum communication,attesting to their uniqueness in transporting high-dimensional quantum states.However,investigations and experiments reported in literature have been carried out in research laboratories,typically making use of short fiber links in controlled environments.Thus,the possibility of using long-distance multicore fibers for quantum applications is still to be proven.We characterize here for the first time,to the best of our knowledge,in terms of phase stability,multiple strands of a four-core multicore fiber installed underground in the city of L’Aquila,with an overall fiber length up to about 25 km.In this preliminary study,we investigate the possibility of using such an infrastructure to implement quantumenhanced schemes,such as high-dimensional quantum key distribution,quantum-based environmental sensors,and more,in general,quantum communication protocols.
