At first, the entanglement source deployment problem is studied in a quantum multi-hop network, which has a significant influence on quantum connectivity. Two optimization algorithms are introduced with limited entang...At first, the entanglement source deployment problem is studied in a quantum multi-hop network, which has a significant influence on quantum connectivity. Two optimization algorithms are introduced with limited entanglement sources in this paper. A deployment algorithm based on node position （DNP） improves connectivity by guaranteeing that all overlapping areas of the distribution ranges of the entanglement sources contain nodes. In addition, a deployment algorithm based on an improved genetic algorithm （DIGA） is implemented by dividing the region into grids. From the simulation results, DNP and DIGA improve quantum connectivity by 213.73% and 248.83% compared to random deployment, respectively, and the latter performs better in terms of connectivity. However, DNP is more flexible and adaptive to change, as it stops running when all nodes are covered.展开更多
Combining a Ti-diffusion periodically poled lithium niobate(PPLN)waveguide with a Sagnac interferometer,two opposite directions type-II spontaneous parametric down conversions(SPDC)occur coherently and yield a high br...Combining a Ti-diffusion periodically poled lithium niobate(PPLN)waveguide with a Sagnac interferometer,two opposite directions type-II spontaneous parametric down conversions(SPDC)occur coherently and yield a high brightness,high stability polarization entanglement source.The source produces degenerate photon pairs at 1540.4 nm with a brightness of B=(1.36±0.03)×10^(6) pairs/(s·nm·m W).We perform quantum state tomography to reconstruct the density matrix of the output state and obtain a fidelity of F=0.983±0.001.The high brightness and phase stability of our waveguide source enable a wide range of quantum information experiments operating at a low pump power as well as hold the advantage in mass production which can promote the practical applications of quantum technologies.展开更多
The quantum entangled photon-pair source,as an essential component of optical quantum systems,holds great potential for applications such as quantum teleportation,quan-tum computing,and quantum imaging.The current wor...The quantum entangled photon-pair source,as an essential component of optical quantum systems,holds great potential for applications such as quantum teleportation,quan-tum computing,and quantum imaging.The current workhorse technique for preparing photon pairs involves performing spon-taneous parametric down conversion(SPDC)in bulk nonlinear crystals.However,the current power consumption and cost of preparing entangled photon-pair sources are relatively high,pos-ing challenges to their integration and scalability.In this paper,we propose a low-power system model for the quantum entan-gled photon-pair source based on SPDC theory and phase matching technology.This model allows us to analyze the per-formance of each module and the influence of component cha-racteristics on the overall system.In our experimental setup,we utilize a 5 mW laser diode and a typical type-II barium metabo-rate(BBO)crystal to prepare an entangled photon-pair source.The experimental results are in excellent agreement with the model,indicating a significant step towards achieving the goal of low-power and low-cost entangled photon-pair sources.This achievement not only contributes to the practical application of quantum entanglement lighting,but also paves the way for the widespread adoption of optical quantum systems in the future.展开更多
We present a stable entangled light source that integrates the pump laser, entanglement generator, detectors, and electronic control systems. By optimizing the design of the mechanical elements and the optical path, t...We present a stable entangled light source that integrates the pump laser, entanglement generator, detectors, and electronic control systems. By optimizing the design of the mechanical elements and the optical path, the size of the source is minimized, and the quantum correlations over 6 d B can be directly provided by the entangled source. The compact and stable entangled light source is suitable for practical applications in quantum information science and technology. The presented protocol provides a useful reference for manufacturing products of bright entangled light sources.展开更多
Quantum microwave photonics(QMWP)is an innovative approach that combines energy-time entangled biphoton sources as the optical carrier with time-correlated single-photon detection for highspeed radio frequency(RF)sign...Quantum microwave photonics(QMWP)is an innovative approach that combines energy-time entangled biphoton sources as the optical carrier with time-correlated single-photon detection for highspeed radio frequency(RF)signal recovery.This groundbreaking method offers unique advantages,such as nonlocal RF signal encoding and robust resistance to dispersion-induced frequency fading.We explore the versatility of processing the quantum microwave photonic signal by utilizing coincidence window selection on the biphoton coincidence distribution.The demonstration includes finely tunable RF phase shifting,flexible multitap transversal filtering(with up to 14 taps),and photonically implemented RF mixing,leveraging the nonlocal RF mapping characteristic of QMWP.These accomplishments significantly enhance the capability of microwave photonic systems in processing ultraweak signals,opening up new possibilities for various applications.展开更多
In a breakthrough that promises to revolutionize quantum photonic systems,researchers have successfully demonstrated a high-performance,ultracompact polarization-entangled photon-pair source using the van der Waalsbas...In a breakthrough that promises to revolutionize quantum photonic systems,researchers have successfully demonstrated a high-performance,ultracompact polarization-entangled photon-pair source using the van der Waalsbased two-dimensional 3R-wS2 crystal.This achievement opens new avenues for integrated quantum technologies,paving the way for advanced applications in quantum computing,communication,and metrology.展开更多
On-chip bright quantum sources with multiplexing ability are extremely high in demand for integrated quantum networks with unprecedented scalability and complexity.Here,we demonstrate a bright and broadband biphoton q...On-chip bright quantum sources with multiplexing ability are extremely high in demand for integrated quantum networks with unprecedented scalability and complexity.Here,we demonstrate a bright and broadband biphoton quantum source with spectral multiplexing generated in a lithium niobate microresonator system.Without introducing the conventional domain poling,the on-chip microdisk produces photon pairs covering a broad bandwidth promised by natural phase matching in spontaneous parametric down conversion.Experimentally,the multiplexed photon pairs are characterized by 30 nm bandwidth limited by the filtering system,providing over 40 multiplexing channels with a 0.8 nm channel spacing.Meanwhile,the generation rate reaches 5.13 MHz/μW with a coincidence-to-accidental ratio up to 804,and the quantum source manifests a high purity with a heralded single photon correlation g^((2))_(H)(0)=0.0098±0.0021.Furthermore,the energy-time entanglement is demonstrated with an excellent interference visibility of 96.5%±2%.Such a quantum source at the telecommunication band paves the way for high-dimensional entanglement and future integrated quantum information systems.展开更多
基金This project was supported by the Na- tional Natural Science Foundation of China （Grant Nos. 61571105 and 61601120）.
文摘At first, the entanglement source deployment problem is studied in a quantum multi-hop network, which has a significant influence on quantum connectivity. Two optimization algorithms are introduced with limited entanglement sources in this paper. A deployment algorithm based on node position （DNP） improves connectivity by guaranteeing that all overlapping areas of the distribution ranges of the entanglement sources contain nodes. In addition, a deployment algorithm based on an improved genetic algorithm （DIGA） is implemented by dividing the region into grids. From the simulation results, DNP and DIGA improve quantum connectivity by 213.73% and 248.83% compared to random deployment, respectively, and the latter performs better in terms of connectivity. However, DNP is more flexible and adaptive to change, as it stops running when all nodes are covered.
基金Project supported by the National Key R&D Program of China(Grant Nos.2022YFF0712800 and 2019YFA0308700)。
文摘Combining a Ti-diffusion periodically poled lithium niobate(PPLN)waveguide with a Sagnac interferometer,two opposite directions type-II spontaneous parametric down conversions(SPDC)occur coherently and yield a high brightness,high stability polarization entanglement source.The source produces degenerate photon pairs at 1540.4 nm with a brightness of B=(1.36±0.03)×10^(6) pairs/(s·nm·m W).We perform quantum state tomography to reconstruct the density matrix of the output state and obtain a fidelity of F=0.983±0.001.The high brightness and phase stability of our waveguide source enable a wide range of quantum information experiments operating at a low pump power as well as hold the advantage in mass production which can promote the practical applications of quantum technologies.
文摘The quantum entangled photon-pair source,as an essential component of optical quantum systems,holds great potential for applications such as quantum teleportation,quan-tum computing,and quantum imaging.The current workhorse technique for preparing photon pairs involves performing spon-taneous parametric down conversion(SPDC)in bulk nonlinear crystals.However,the current power consumption and cost of preparing entangled photon-pair sources are relatively high,pos-ing challenges to their integration and scalability.In this paper,we propose a low-power system model for the quantum entan-gled photon-pair source based on SPDC theory and phase matching technology.This model allows us to analyze the per-formance of each module and the influence of component cha-racteristics on the overall system.In our experimental setup,we utilize a 5 mW laser diode and a typical type-II barium metabo-rate(BBO)crystal to prepare an entangled photon-pair source.The experimental results are in excellent agreement with the model,indicating a significant step towards achieving the goal of low-power and low-cost entangled photon-pair sources.This achievement not only contributes to the practical application of quantum entanglement lighting,but also paves the way for the widespread adoption of optical quantum systems in the future.
基金supported by the National Natural Science Foundation of China(Grant No.61227015)the Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi,China
文摘We present a stable entangled light source that integrates the pump laser, entanglement generator, detectors, and electronic control systems. By optimizing the design of the mechanical elements and the optical path, the size of the source is minimized, and the quantum correlations over 6 d B can be directly provided by the entangled source. The compact and stable entangled light source is suitable for practical applications in quantum information science and technology. The presented protocol provides a useful reference for manufacturing products of bright entangled light sources.
基金supported by the National Natural Science Foundation of China(Grant Nos.12033007,61801458,12103058,12203058,12074309,and 61875205)the Youth Innovation Promotion Association,CAS(Grant Nos.2021408,2022413,and 2023425)the China Postdoctoral Science Foundation(Grant No.2022M723174).
文摘Quantum microwave photonics(QMWP)is an innovative approach that combines energy-time entangled biphoton sources as the optical carrier with time-correlated single-photon detection for highspeed radio frequency(RF)signal recovery.This groundbreaking method offers unique advantages,such as nonlocal RF signal encoding and robust resistance to dispersion-induced frequency fading.We explore the versatility of processing the quantum microwave photonic signal by utilizing coincidence window selection on the biphoton coincidence distribution.The demonstration includes finely tunable RF phase shifting,flexible multitap transversal filtering(with up to 14 taps),and photonically implemented RF mixing,leveraging the nonlocal RF mapping characteristic of QMWP.These accomplishments significantly enhance the capability of microwave photonic systems in processing ultraweak signals,opening up new possibilities for various applications.
文摘In a breakthrough that promises to revolutionize quantum photonic systems,researchers have successfully demonstrated a high-performance,ultracompact polarization-entangled photon-pair source using the van der Waalsbased two-dimensional 3R-wS2 crystal.This achievement opens new avenues for integrated quantum technologies,paving the way for advanced applications in quantum computing,communication,and metrology.
基金supported by the National Key R&D Program of China(Grant Nos.2016YFA0301302,and 2016YFA0301700)National Natural Science Foundation of China(Grant Nos.11825402,61590932,11774333,62061160487,12004373,11734009,and 11874375)+4 种基金Anhui Initiative in Quantum Information Technologies(Grant No.AHY130300)Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB24030601)Beijing Academy of Quantum Information Sciences(Grant No.Y18G20)Fundamental Research Funds for the Central Universitiespartially carried out at the USTC Center for Micro and Nanoscale Research and Fabrication。
文摘On-chip bright quantum sources with multiplexing ability are extremely high in demand for integrated quantum networks with unprecedented scalability and complexity.Here,we demonstrate a bright and broadband biphoton quantum source with spectral multiplexing generated in a lithium niobate microresonator system.Without introducing the conventional domain poling,the on-chip microdisk produces photon pairs covering a broad bandwidth promised by natural phase matching in spontaneous parametric down conversion.Experimentally,the multiplexed photon pairs are characterized by 30 nm bandwidth limited by the filtering system,providing over 40 multiplexing channels with a 0.8 nm channel spacing.Meanwhile,the generation rate reaches 5.13 MHz/μW with a coincidence-to-accidental ratio up to 804,and the quantum source manifests a high purity with a heralded single photon correlation g^((2))_(H)(0)=0.0098±0.0021.Furthermore,the energy-time entanglement is demonstrated with an excellent interference visibility of 96.5%±2%.Such a quantum source at the telecommunication band paves the way for high-dimensional entanglement and future integrated quantum information systems.
基金the financial support from the National Natural Science Foundation of China(11774326)the National Key R&D Program of China(2017YFA0304301)+2 种基金Innovation Program for Quantum Science and Technology(2021ZD0300204)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Anhui Initiative in Quantum Information Technologies。
