We propose a hybrid silicon waveguide scheme to avoid the impact of noise photons induced by pump lights in application scenarios of quantum photonic circuits with quantum light sources.The scheme is composed of strip...We propose a hybrid silicon waveguide scheme to avoid the impact of noise photons induced by pump lights in application scenarios of quantum photonic circuits with quantum light sources.The scheme is composed of strip waveguide and shallow-ridge waveguide structures.It utilizes the difference of biphoton spectra generated by spontaneous four-wave mixing(SFWM)in these two waveguides.By proper pumping setting and signal/idler wavelength selection,the generation of desired photon pairs is confined in the strip waveguide.The impact of noise photons generated by SFWM in the shallow-ridge waveguide can be avoided.Hence,the shallowridge waveguide could be used to realize various linear operation devices for pump light and quantum state manipulations.The feasibility of this scheme is verified by theoretical analysis and a primary experiment.Two applications are proposed and analyzed,showing its great potential in silicon-based quantum photonic circuits.展开更多
Quantum teleportation can transfer an unknown quantum state between distant quantum nodes,which holds great promise in enabling large-scale quantum networks.To advance the full potential of quantum teleportation,quant...Quantum teleportation can transfer an unknown quantum state between distant quantum nodes,which holds great promise in enabling large-scale quantum networks.To advance the full potential of quantum teleportation,quantum states must be faithfully transferred at a high rate over long distance.Despite recent impressive advances,a high-rate quantum teleportation system across metropolitan fiber networks is extremely desired.Here,we demonstrate a quantum teleportation system which transfers quantum states carried by independent photons at a rate of 7.1±0.4 Hz over 64-km-long fiber channel.An average single-photon fidelity of≥90.6±2.6%is achieved,which exceeds the maximum fidelity of 2/3 in classical regime.Our result marks an important milestone towards quantum networks and opens the door to exploring quantum entanglement based informatic applications for the future quantum internet.展开更多
Entangled photon pairs are crucial resources for quantum information processing protocols.Via the process of spontaneous parametric downconversion(SPDC),we can generate these photon pairs using bulk nonlinear crystals...Entangled photon pairs are crucial resources for quantum information processing protocols.Via the process of spontaneous parametric downconversion(SPDC),we can generate these photon pairs using bulk nonlinear crystals.Traditionally,the crystal is designed to satisfy a specific type of phase-matching condition.Here,we report controllable transitions among different types of phase matching in a single periodically poled potassium titanyl phosphate crystal.By carefully selecting pump conditions,we can satisfy different phase-matching conditions.This allows us to observe first-order Type-II,fifth-order Type-I,third-order Type-0,and fifth-order Type-II SPDCs.The temperature-dependent spectra of our source were also analyzed in detail.Finally,we discussed the possibility of observing more than nine SPDCs in this crystal.Our work not only deepens the understanding of the physics behind phase-matching conditions,but also offers the potential for a highly versatile entangled biphoton source for quantum information research.展开更多
Heralded single-photon source(HSPS)intrinsically suffers from the trade-off between the heralded single-photon rate and the single-photon purity.To break through this trade-off,one can apply multiplexing technology in...Heralded single-photon source(HSPS)intrinsically suffers from the trade-off between the heralded single-photon rate and the single-photon purity.To break through this trade-off,one can apply multiplexing technology in different degrees of freedom that significantly improves the performance of the HSPS.Here,we propose a 1.5μm chip-scale HSPS on lithium niobate on insulator by employing spectral multiplexing and active feedforward spectral manipulating,and we demonstrate a proof-of-principle experiment with discrete fiber-based components.With continuous-wave laser pumping and three spectral modes multiplexed,our experimental results show that the spectral multiplexing improves the heralded single-photon rate by near threefold while keeping the g^((2))(0)as low as 0.0006±0.0001 at a measured single-photon rate of 3.1 kHz.By measuring the joint spectral intensity,we show that the spectral multiplexing and feed-forward control effectively erase the frequency correlation of photon pairs.Moreover,we implement the Hong-Ou-Mandel interference between the spectrally multiplexed single photons and photons from an independent weak coherence source,which indicates that the multiplexed single photons are highly indistinguishable after the spectral manipulation.Our results pave a way for on-chip scalable and high-performance HSPS with spectral multiplexing toward deterministic single-photon emission.展开更多
基金National Key R&D Program of China(2017YFA0303704,2018YFB2200400)National Natural Science Foundation of China(61575102,61621064,61875101,91750206)+1 种基金Natural Science Foundation of Beijing Municipality(Z180012)Beijing Academy of Quantum Information Sciences(Y18G26)。
文摘We propose a hybrid silicon waveguide scheme to avoid the impact of noise photons induced by pump lights in application scenarios of quantum photonic circuits with quantum light sources.The scheme is composed of strip waveguide and shallow-ridge waveguide structures.It utilizes the difference of biphoton spectra generated by spontaneous four-wave mixing(SFWM)in these two waveguides.By proper pumping setting and signal/idler wavelength selection,the generation of desired photon pairs is confined in the strip waveguide.The impact of noise photons generated by SFWM in the shallow-ridge waveguide can be avoided.Hence,the shallowridge waveguide could be used to realize various linear operation devices for pump light and quantum state manipulations.The feasibility of this scheme is verified by theoretical analysis and a primary experiment.Two applications are proposed and analyzed,showing its great potential in silicon-based quantum photonic circuits.
基金This work was supported by the National Key Research and Development Program of China(Nos.2018YFA0307400,2018YFA0306102)National Natural Science Foundation of China(Nos.61775025,91836102,U19A2076,62005039)+1 种基金Innovation Program for Quantum Science and Technology(No.2021ZD0301702)Sichuan Science and Technology Program(Nos.2021YFSY0066,2021YFSY0062,2021YFSY0063,2021YFSY0064,2021YFSY0065).The authors thank X.X.H,Y.X.L and L.B.Z from the Information Center of the University of Electronic Science and Technology of China(UESTC)for providing access to the campus fiber network and for the help during the experiment.
文摘Quantum teleportation can transfer an unknown quantum state between distant quantum nodes,which holds great promise in enabling large-scale quantum networks.To advance the full potential of quantum teleportation,quantum states must be faithfully transferred at a high rate over long distance.Despite recent impressive advances,a high-rate quantum teleportation system across metropolitan fiber networks is extremely desired.Here,we demonstrate a quantum teleportation system which transfers quantum states carried by independent photons at a rate of 7.1±0.4 Hz over 64-km-long fiber channel.An average single-photon fidelity of≥90.6±2.6%is achieved,which exceeds the maximum fidelity of 2/3 in classical regime.Our result marks an important milestone towards quantum networks and opens the door to exploring quantum entanglement based informatic applications for the future quantum internet.
基金supported by the National Natural Science Foundation of China(Nos.12074299,11704290,and 92365106)the Guangdong Provincial Key Laboratory(No.GKLQSE202102)the Natural Science Foundation of Hubei Province(2022CFA039)。
文摘Entangled photon pairs are crucial resources for quantum information processing protocols.Via the process of spontaneous parametric downconversion(SPDC),we can generate these photon pairs using bulk nonlinear crystals.Traditionally,the crystal is designed to satisfy a specific type of phase-matching condition.Here,we report controllable transitions among different types of phase matching in a single periodically poled potassium titanyl phosphate crystal.By carefully selecting pump conditions,we can satisfy different phase-matching conditions.This allows us to observe first-order Type-II,fifth-order Type-I,third-order Type-0,and fifth-order Type-II SPDCs.The temperature-dependent spectra of our source were also analyzed in detail.Finally,we discussed the possibility of observing more than nine SPDCs in this crystal.Our work not only deepens the understanding of the physics behind phase-matching conditions,but also offers the potential for a highly versatile entangled biphoton source for quantum information research.
基金Sichuan Province Science and Technology Support Program(2018JY0084)National Key Research and Development Program of China(2017YFA0304000,2017YFB0405100,2018YFA0306102,2018YFA0307400,2019YFB2203400)National Natural Science Foundation of China(12074058,61405030,61704164,61775025,62005039,62075034,91836102,U19A2076)。
文摘Heralded single-photon source(HSPS)intrinsically suffers from the trade-off between the heralded single-photon rate and the single-photon purity.To break through this trade-off,one can apply multiplexing technology in different degrees of freedom that significantly improves the performance of the HSPS.Here,we propose a 1.5μm chip-scale HSPS on lithium niobate on insulator by employing spectral multiplexing and active feedforward spectral manipulating,and we demonstrate a proof-of-principle experiment with discrete fiber-based components.With continuous-wave laser pumping and three spectral modes multiplexed,our experimental results show that the spectral multiplexing improves the heralded single-photon rate by near threefold while keeping the g^((2))(0)as low as 0.0006±0.0001 at a measured single-photon rate of 3.1 kHz.By measuring the joint spectral intensity,we show that the spectral multiplexing and feed-forward control effectively erase the frequency correlation of photon pairs.Moreover,we implement the Hong-Ou-Mandel interference between the spectrally multiplexed single photons and photons from an independent weak coherence source,which indicates that the multiplexed single photons are highly indistinguishable after the spectral manipulation.Our results pave a way for on-chip scalable and high-performance HSPS with spectral multiplexing toward deterministic single-photon emission.
