High-capacity,long-distance underwater optical communication enables a global scale optical network covering orbit,land,and water.Underwater communication using photons as carriers has a high channel capacity;however,...High-capacity,long-distance underwater optical communication enables a global scale optical network covering orbit,land,and water.Underwater communication using photons as carriers has a high channel capacity;however,the light scattering and absorption of water lead to an inevitable huge channel loss,setting an insurmountable transmission distance for existing underwater optical communication technologies.Here,we experimentally demonstrate the photon-inter-correlation optical communication(PICOC)in air-water scenarios.We retrieve additional internal correlation resources from the sparse single-photon stream with high fidelity.We successfully realize the 105-m-long underwater optical communication against a total loss up to 120.1 d B using only a microwatt laser.The demonstrated underwater light attenuation is equivalent to the loss of 883-m-long Jerlov type I water,encouraging the practical air-water optical communication to connect deeper underwater worlds.展开更多
Squeezed light is a critical resource in quantum sensing and information processing. Due to the inherently weak optical nonlinearity and limited interaction volume, considerable pump power is typically needed to obtai...Squeezed light is a critical resource in quantum sensing and information processing. Due to the inherently weak optical nonlinearity and limited interaction volume, considerable pump power is typically needed to obtain efficient interactions to generate squeezed light in bulk crystals. Integrated photonics offers an elegant way to increase the nonlinearity by confining light strictly inside the waveguide. For the construction of large-scale quantum systems performing many-photon operations, it is essential to integrate various functional modules on a chip. However, fabrication imperfections and transmission cross talk may add unwanted diffraction and coupling to other photonic elements, reducing the quality of squeezing. Here, by introducing the topological phase, we experimentally demonstrate the topologically protected nonlinear process of four-wave mixing, enabling the generation of squeezed light on a silica chip. We measure the cross-correlations at different evolution distances for various topological sites and verify the nonclassical features with high fidelity. The squeezing parameters are measured to certify the protection of cavity-free, strongly squeezed states. The demonstration of topological protection for squeezed light on a chip brings new opportunities for quantum integrated photonics,opening novel approaches for the design of advanced multi-photon circuits.展开更多
Dynamic localization,which originates from the phenomena of particle evolution suppression under an externally applied AC electric field,has been simulated by suppressed light evolution in periodically curved photonic...Dynamic localization,which originates from the phenomena of particle evolution suppression under an externally applied AC electric field,has been simulated by suppressed light evolution in periodically curved photonic arrays.However,experimental studies on their quantitative dynamic transport properties and application for quantum information processing are rare.Here we fabricate one-dimensional and hexagonal two-dimensional arrays both with sinusoidal curvatures.We successfully observe the suppressed single-photon evolution patterns,and for the first time,to the best of our knowledge,measure the variances to study their transport properties.For onedimensional arrays,the measured variances match both the analytical electric-field calculation and the quantum walk Hamiltonian engineering approach.For hexagonal arrays as anisotropic effective couplings in four directions are mutually dependent,the analytical approach suffers,whereas quantum walk conveniently incorporates all anisotropic coupling coefficients in the Hamiltonian and solves its exponential as a whole,yielding consistent variances with our experimental results.Furthermore,we implement a nearly complete localization to show that it can preserve both the initial injection and the wave packet after some evolution,acting as a memory of a flexible time scale in integrated photonics.We demonstrate a useful quantum simulation of dynamic localization for studying their anisotropic transport properties and a promising application of dynamic localization as a building block for quantum information processing in integrated photonics.展开更多
To realize a large-scale quantum network,both quantum memory and the interference of retrieved indistinguishable photons are essentially required to perform multi-photon synchronization and quantum-interference-mediat...To realize a large-scale quantum network,both quantum memory and the interference of retrieved indistinguishable photons are essentially required to perform multi-photon synchronization and quantum-interference-mediated entanglement swapping.Significant progress has been achieved in low-temperature and well-isolated systems.However,linking independent quantum memories at room temperature remain challenging.Here,we present an experimental demonstration of Hong–Ou–Mandel interference between single photons from two independent room-temperature quantum memories.We manage to simultaneously operate two such quantum memories and individually obtain a memory-built-in quantum correlation of Stokes and anti-Stokes photons by a far-off-resonance Duan–Lukin–Cirac–Zoller protocol.We also successfully enhance the Hong–Ou–Mandel interference rate up to about 15 times by increasing each photon rate,which is achieved by coordinating two quantum memories with a repeat-until-success fashion.We observe the visibility of quantum interference up to 75.0%without reduction of any background noise,well exceeding the classical limit of 50%.Our results,together with its straightforward,broadband,and room-temperature features,open up a promising way towards realizing large-scale quantum networks at ambient conditions.展开更多
基金National Key Research and Development Program of China(2019YFA0706302,2017YFA0303700,2019YFA0308700)National Natural Science Foundation of China(11690033,11761141014,11904229,61734005)+2 种基金Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Shanghai Municipal Education Commission(2017-01-07-00-02-E00049)Science and Technology Commission of Shanghai Municipality(17JC1400403)。
文摘High-capacity,long-distance underwater optical communication enables a global scale optical network covering orbit,land,and water.Underwater communication using photons as carriers has a high channel capacity;however,the light scattering and absorption of water lead to an inevitable huge channel loss,setting an insurmountable transmission distance for existing underwater optical communication technologies.Here,we experimentally demonstrate the photon-inter-correlation optical communication(PICOC)in air-water scenarios.We retrieve additional internal correlation resources from the sparse single-photon stream with high fidelity.We successfully realize the 105-m-long underwater optical communication against a total loss up to 120.1 d B using only a microwatt laser.The demonstrated underwater light attenuation is equivalent to the loss of 883-m-long Jerlov type I water,encouraging the practical air-water optical communication to connect deeper underwater worlds.
基金National Key R&D Program of China(2019YFA0308700, 2019YFA0706302, 2017YFA0303700)National Natural Science Foundation of China (NSFC)(11904229, 61734005, 11761141014, 11690033)+4 种基金Science and Technology Commission of Shanghai Municipality (STCSM)(20JC1416300, 2019SHZDZX01)Shanghai Municipal Education Commission (SMEC)(2017-01-07-00-02-E00049)China Postdoctoral Science Foundation (2020M671091)Australian Research Council (DE180100070)University of Technology Sydney Seed Fund。
文摘Squeezed light is a critical resource in quantum sensing and information processing. Due to the inherently weak optical nonlinearity and limited interaction volume, considerable pump power is typically needed to obtain efficient interactions to generate squeezed light in bulk crystals. Integrated photonics offers an elegant way to increase the nonlinearity by confining light strictly inside the waveguide. For the construction of large-scale quantum systems performing many-photon operations, it is essential to integrate various functional modules on a chip. However, fabrication imperfections and transmission cross talk may add unwanted diffraction and coupling to other photonic elements, reducing the quality of squeezing. Here, by introducing the topological phase, we experimentally demonstrate the topologically protected nonlinear process of four-wave mixing, enabling the generation of squeezed light on a silica chip. We measure the cross-correlations at different evolution distances for various topological sites and verify the nonclassical features with high fidelity. The squeezing parameters are measured to certify the protection of cavity-free, strongly squeezed states. The demonstration of topological protection for squeezed light on a chip brings new opportunities for quantum integrated photonics,opening novel approaches for the design of advanced multi-photon circuits.
基金National Natural Science Foundation of China(11690033,11761141014,11904229,61734005)National Key Research and Development Program of China(2017YFA0303700,2019YFA0308700,2019YFA0706302)+2 种基金Science and Technology Commission of Shanghai Municipality(STCSM)(21ZR1432800,20JC1416300,2019SHZDZX01)Shanghai Municipal Education Commission(SMEC)(2017-01-07-00-02-E00049)Shanghai talent program,Shanghai Jiao Tong University。
文摘Dynamic localization,which originates from the phenomena of particle evolution suppression under an externally applied AC electric field,has been simulated by suppressed light evolution in periodically curved photonic arrays.However,experimental studies on their quantitative dynamic transport properties and application for quantum information processing are rare.Here we fabricate one-dimensional and hexagonal two-dimensional arrays both with sinusoidal curvatures.We successfully observe the suppressed single-photon evolution patterns,and for the first time,to the best of our knowledge,measure the variances to study their transport properties.For onedimensional arrays,the measured variances match both the analytical electric-field calculation and the quantum walk Hamiltonian engineering approach.For hexagonal arrays as anisotropic effective couplings in four directions are mutually dependent,the analytical approach suffers,whereas quantum walk conveniently incorporates all anisotropic coupling coefficients in the Hamiltonian and solves its exponential as a whole,yielding consistent variances with our experimental results.Furthermore,we implement a nearly complete localization to show that it can preserve both the initial injection and the wave packet after some evolution,acting as a memory of a flexible time scale in integrated photonics.We demonstrate a useful quantum simulation of dynamic localization for studying their anisotropic transport properties and a promising application of dynamic localization as a building block for quantum information processing in integrated photonics.
基金National Key Research and Development Program of China(2019YFA0706302,2019YFA0308700,2017YFA0303700)National Natural Science Foundation of China(NSFC)(11904229,61734005,11761141014,11690033)+4 种基金Science and Technology Commission of Shanghai Municipality(STCSM)(20JC1416300,2019SHZDZX01)Shanghai Municipal Education Commission(SMEC)(2017-01-07-00-02-E00049)China Postdoctoral Science Foundation(2020M671091)Shanghai Talent ProgramZhiyuan Innovative Research Center of Shanghai Jiao Tong University.
文摘To realize a large-scale quantum network,both quantum memory and the interference of retrieved indistinguishable photons are essentially required to perform multi-photon synchronization and quantum-interference-mediated entanglement swapping.Significant progress has been achieved in low-temperature and well-isolated systems.However,linking independent quantum memories at room temperature remain challenging.Here,we present an experimental demonstration of Hong–Ou–Mandel interference between single photons from two independent room-temperature quantum memories.We manage to simultaneously operate two such quantum memories and individually obtain a memory-built-in quantum correlation of Stokes and anti-Stokes photons by a far-off-resonance Duan–Lukin–Cirac–Zoller protocol.We also successfully enhance the Hong–Ou–Mandel interference rate up to about 15 times by increasing each photon rate,which is achieved by coordinating two quantum memories with a repeat-until-success fashion.We observe the visibility of quantum interference up to 75.0%without reduction of any background noise,well exceeding the classical limit of 50%.Our results,together with its straightforward,broadband,and room-temperature features,open up a promising way towards realizing large-scale quantum networks at ambient conditions.