To meet the needs of signal alignment between the transmitter and receiver in a quantum key distribution(QKD) system, we put forward a TDC-GPX-based synchronization scheme, which is based on high-precision time measur...To meet the needs of signal alignment between the transmitter and receiver in a quantum key distribution(QKD) system, we put forward a TDC-GPX-based synchronization scheme, which is based on high-precision time measurement. We send a low-frequency repeat optical pulse synchronized with associated quantum signals on the receiver's side by using a time-to-digital converter(TDC)module, the time intervals between quantum signals, and synchronization signals measured and converted to corresponding temporal orders to complete the synchronization.We state the principle of the synchronization scheme in detail and then verify it in an actual QKD test bed. The test results show that our TDC-GPX-based synchronization can obtain a time resolution better than 100 ps, and the proposed scheme shows full feasibility for an actual QKD system.展开更多
We demonstrate a three-node active quantum key distribution(QKD)network with our previous two-way QKD system.An optical switch is used as a router to connect the two nodes.Adjacent nodes are connected by a 25 km optic...We demonstrate a three-node active quantum key distribution(QKD)network with our previous two-way QKD system.An optical switch is used as a router to connect the two nodes.Adjacent nodes are connected by a 25 km optical fiber.The test over 11 h shows that our system can reduce the Raleigh backscattering efficiently in the absence of the storage fiber.Furthermore,the obtained average sifted key is about 1.2 kbps in the network,with high visibility and low quantum bit error rate in the long-time test.展开更多
In this communication, we report results of running tests on standard telecommunication metropolitan network 1550 nm fiber applied to a quantum channel to EPR S405 Quelle prototype systems installed in National Labora...In this communication, we report results of running tests on standard telecommunication metropolitan network 1550 nm fiber applied to a quantum channel to EPR S405 Quelle prototype systems installed in National Laboratory for Quantum Technologies WUT and in CompSecur Wroclaw. Testing was carried out by means of the original design by us and applied special data card collecting parameters of functioning system allowing for assessment of quality of quantum channel. We have performed several trials using various configurations of standard 1550 nm fiber patch-cord up to length of 6.5 km with additional usage of various patch-cords with weldings and connectors which typically present in already installed commercial metropolitan communication networks. The implementation of this testing indicated that the rigorous maintenance of photon polarization is required for quantum information exchange upon EPR S405 Quelle functioning. The polarization of optical signal turned out to be, however, very unstable for the tested connection which resulted in very rapid QBER rise precluding practical usefulness of this connection for secure quantum exchange of cryptographic key over practically significant distances. We have identified that the main obstacle was the polarization decoherence caused by weldings and connectors in standard patch-cords and accidental strains in fibers as well as generally poor transmitting properties of 1550 nm fiber for much shorter wave-length photons used by the Quelle system. To maintain the quantum channel active, very frequent manual corrections of polarization control were required. So we expect that by design and application of an automatic polarization control module, one would stabilize visibility ratio and lower QBER to an acceptable level conditioning possible future implementation of entangled QKD system in commercial networks.展开更多
Quantum key distribution(QKD)is nowadays a well-established method for generating secret keys at a distance in an information-theoretically secure way,as the secrecy of QKD relies on the laws of quantum physics and no...Quantum key distribution(QKD)is nowadays a well-established method for generating secret keys at a distance in an information-theoretically secure way,as the secrecy of QKD relies on the laws of quantum physics and not on computational complexity.In order to industrialize QKD,low-cost,mass-manufactured,and practical QKD setups are required.Hence,photonic and electronic integration of the sender's and receiver's respective components is currently in the spotlight.Here we present a high-speed(2.5 GHz)integrated QKD setup featuring a transmitter chip in silicon photonics allowing for high-speed modulation and accurate state preparation,as well as a polarization-independent low-loss receiver chip in aluminum borosilicate glass fabricated by the femtosecond laser micromachining technique.Our system achieves raw bit error rates,quantum bit error rates,and secret key rates equivalent to a much more complex state-of-the-art setup based on discrete components[A.Boaron et al.,Phys.Rev.Lett.121,190502(2018)].展开更多
We develop a quantum key distribution (QKD) system with fast active optical path length compensation. A rapid and reliable active optical path length compensation scheme is proposed and applied to a plug-and-play QKD ...We develop a quantum key distribution (QKD) system with fast active optical path length compensation. A rapid and reliable active optical path length compensation scheme is proposed and applied to a plug-and-play QKD system. The system monitors changes in key rates and controls it is own operation automatically. The system achieves its optimal performance within three seconds of operation, which includes a sifted key rate of 5.5 kbps and a quantum bit error rate of less than 2% after an abrupt temperature variation along the 25 km quantum channel. The system also operates well over a 24 h period while completing more than 60 active optical path length compensations.展开更多
Quantum key distribution(QKD)is a technology that can resist the threat of quantum computers to existing conventional cryptographic protocols.However,due to the stringent requirements of the quantum key generation env...Quantum key distribution(QKD)is a technology that can resist the threat of quantum computers to existing conventional cryptographic protocols.However,due to the stringent requirements of the quantum key generation environment,the generated quantum keys are considered valuable,and the slow key generation rate conflicts with the high-speed data transmission in traditional optical networks.In this paper,for the QKD network with a trusted relay,which is mainly based on point-to-point quantum keys and has complex changes in network resources,we aim to allocate resources reasonably for data packet distribution.Firstly,we formulate a linear programming constraint model for the key resource allocation(KRA)problem based on the time-slot scheduling.Secondly,we propose a new scheduling scheme based on the graded key security requirements(GKSR)and a new micro-log key storage algorithm for effective storage and management of key resources.Finally,we propose a key resource consumption(KRC)routing optimization algorithm to properly allocate time slots,routes,and key resources.Simulation results show that the proposed scheme significantly improves the key distribution success rate and key resource utilization rate,among others.展开更多
基金supported by National Natural Science Foundation of China (Nos. 11375195, 11375263 and 11105143)National Magnetic Confinement Fusion Energy Development Research (No. 2013GB104003)
文摘To meet the needs of signal alignment between the transmitter and receiver in a quantum key distribution(QKD) system, we put forward a TDC-GPX-based synchronization scheme, which is based on high-precision time measurement. We send a low-frequency repeat optical pulse synchronized with associated quantum signals on the receiver's side by using a time-to-digital converter(TDC)module, the time intervals between quantum signals, and synchronization signals measured and converted to corresponding temporal orders to complete the synchronization.We state the principle of the synchronization scheme in detail and then verify it in an actual QKD test bed. The test results show that our TDC-GPX-based synchronization can obtain a time resolution better than 100 ps, and the proposed scheme shows full feasibility for an actual QKD system.
基金Supported by the National Natural Science Foundation of China Grant No 61072071.
文摘We demonstrate a three-node active quantum key distribution(QKD)network with our previous two-way QKD system.An optical switch is used as a router to connect the two nodes.Adjacent nodes are connected by a 25 km optical fiber.The test over 11 h shows that our system can reduce the Raleigh backscattering efficiently in the absence of the storage fiber.Furthermore,the obtained average sifted key is about 1.2 kbps in the network,with high visibility and low quantum bit error rate in the long-time test.
文摘In this communication, we report results of running tests on standard telecommunication metropolitan network 1550 nm fiber applied to a quantum channel to EPR S405 Quelle prototype systems installed in National Laboratory for Quantum Technologies WUT and in CompSecur Wroclaw. Testing was carried out by means of the original design by us and applied special data card collecting parameters of functioning system allowing for assessment of quality of quantum channel. We have performed several trials using various configurations of standard 1550 nm fiber patch-cord up to length of 6.5 km with additional usage of various patch-cords with weldings and connectors which typically present in already installed commercial metropolitan communication networks. The implementation of this testing indicated that the rigorous maintenance of photon polarization is required for quantum information exchange upon EPR S405 Quelle functioning. The polarization of optical signal turned out to be, however, very unstable for the tested connection which resulted in very rapid QBER rise precluding practical usefulness of this connection for secure quantum exchange of cryptographic key over practically significant distances. We have identified that the main obstacle was the polarization decoherence caused by weldings and connectors in standard patch-cords and accidental strains in fibers as well as generally poor transmitting properties of 1550 nm fiber for much shorter wave-length photons used by the Quelle system. To maintain the quantum channel active, very frequent manual corrections of polarization control were required. So we expect that by design and application of an automatic polarization control module, one would stabilize visibility ratio and lower QBER to an acceptable level conditioning possible future implementation of entangled QKD system in commercial networks.
基金Eurostars Projects(E!11493)European Quantum Flagship project openQKD(857156)+1 种基金Italian Ministry for University and Research(PRIN2017-SRNBRK,PNRR-NQSTI)European Research Council(742745)。
文摘Quantum key distribution(QKD)is nowadays a well-established method for generating secret keys at a distance in an information-theoretically secure way,as the secrecy of QKD relies on the laws of quantum physics and not on computational complexity.In order to industrialize QKD,low-cost,mass-manufactured,and practical QKD setups are required.Hence,photonic and electronic integration of the sender's and receiver's respective components is currently in the spotlight.Here we present a high-speed(2.5 GHz)integrated QKD setup featuring a transmitter chip in silicon photonics allowing for high-speed modulation and accurate state preparation,as well as a polarization-independent low-loss receiver chip in aluminum borosilicate glass fabricated by the femtosecond laser micromachining technique.Our system achieves raw bit error rates,quantum bit error rates,and secret key rates equivalent to a much more complex state-of-the-art setup based on discrete components[A.Boaron et al.,Phys.Rev.Lett.121,190502(2018)].
基金was supported by the ICT R&D programs of Ministry of Science, ICT and Future Planning/Institute for Information & Communications Technology Promotion (Grant No. B0101-16-1355)the Korea Institute of Science and Technology research program (Grant No. 2E27231)Korea Institute of Science and Technology-Electronics And Telecommunications Research Institute research program (Grant No. 2V05340)
文摘We develop a quantum key distribution (QKD) system with fast active optical path length compensation. A rapid and reliable active optical path length compensation scheme is proposed and applied to a plug-and-play QKD system. The system monitors changes in key rates and controls it is own operation automatically. The system achieves its optimal performance within three seconds of operation, which includes a sifted key rate of 5.5 kbps and a quantum bit error rate of less than 2% after an abrupt temperature variation along the 25 km quantum channel. The system also operates well over a 24 h period while completing more than 60 active optical path length compensations.
基金Project supported by the Natural Science Foundation of Jilin Province of China(Grant No.20210101417JC).
文摘Quantum key distribution(QKD)is a technology that can resist the threat of quantum computers to existing conventional cryptographic protocols.However,due to the stringent requirements of the quantum key generation environment,the generated quantum keys are considered valuable,and the slow key generation rate conflicts with the high-speed data transmission in traditional optical networks.In this paper,for the QKD network with a trusted relay,which is mainly based on point-to-point quantum keys and has complex changes in network resources,we aim to allocate resources reasonably for data packet distribution.Firstly,we formulate a linear programming constraint model for the key resource allocation(KRA)problem based on the time-slot scheduling.Secondly,we propose a new scheduling scheme based on the graded key security requirements(GKSR)and a new micro-log key storage algorithm for effective storage and management of key resources.Finally,we propose a key resource consumption(KRC)routing optimization algorithm to properly allocate time slots,routes,and key resources.Simulation results show that the proposed scheme significantly improves the key distribution success rate and key resource utilization rate,among others.
