Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2012.06092 · Physical Review Applied

Ultrabright Multiplexed Energy-Time-Entangled Photon Generation from Lithium Niobate on Insulator Chip

Guang-Tai Xue, Yun-Fei Niu, Xiaoyue Liu, Jia-Chen Duan, Wenjun Chen, Ying Pan, Kunpeng Jia, Xiaohan Wang, Hua-Ying Liu, Yong Zhang, Ping Xu, Gang Zhao, Xinlun Cai, Yan-Xiao Gong, Xiaopeng Hu, Zhenda Xie, Shining Zhu

Published Jun 24, 2021• 109 citations
arXivHTMLPDF

Abstract

A high-flux entangled-photon source is a key resource for quantum optical study and application. Here, it is realized in a lithium niobate on isolator (LNOI) chip, with 2.79 \ifmmode\times\else\texttimes\fi{} ${10}^{11}$ Hz/mW photon-pair rate and 1.53 \ifmmode\times\else\texttimes\fi{} ${10}^{9}$ Hz/(nm mW) spectral brightness. These data are boosted by over 2 orders of magnitude compared with existing technologies. A 160-nm-broad bandwidth is engineered for eight-channel multiplexed energy-time entanglement. Harnessed by high-extinction-frequency correlation and Franson interferences up to 99.17% visibility, such energy-time-entanglement multiplexing further enhances the high-flux data rate and warrants broad application in quantum-information processing on a chip.

DOI
10.1103/physrevapplied.15.064059

Related papers

Spectrally multiplexed and ultrabright entangled photon pairs in a lithium niobate microresonator

Boyu Xu, Likun Chen, Jintian Lin +10 more

On-chip bright quantum sources with multiplexing ability are extremely high in demand for the integrated quantum networks with unprecedented scalability and complexity. Here, we demonstrate an ultrabright and broadband biphoton quantum source generated in a lithium niobate microresonator system.Without introducing the conventional domain poling, the on-chip microdisk produces entangled photon pairs covering a broad bandwidth promised by natural phase matching in spontaneous parametric down conversion.Experimentally, the multiplexed photon pairs are characterized by $30\ \rm nm$ bandwidth limited by the filtering system, which can be furthered enlarged.Meanwhile, the generation rate reaches $5.13\ {\rm MHz}/\upmu \rm W$ with a coincidence-to-accidental ratio up to $804$.Besides, the quantum source manifests the prominent purity with heralded single photon correlation $g_H^{(2)}(0)=0.0098\pm0.0021$ and energy-time entanglement with excellent interference visibility of $96.5\%\pm1.9\%$. Such quantum sources at the telecommunication band pave the way for high-dimensional entanglement and future integrated quantum information systems.

arXiv:2110.08997•Oct 18, 2021•0 citations

Chip-Integrated Broadband Multi-Photon Source for Wavelength-Multiplexed Quantum Networks

Xiao-Xu Fang, Ling-Xuan Kong, He Lu

Quantum networks based on wavelength-multiplexed entanglement enable parallel distribution of quantum correlations, increasing channel capacity for secure communication and distributed quantum information processing. However, broadband integrated sources capable of generating multipartite entanglement beyond photon pairs remain scarce. Here we report on-chip generation of telecom-band four-photon entanglement in a periodically poled thin-film lithium niobate on insulator (LNOI) waveguide. Type-0 spontaneous parametric down-conversion provides a phase-matching bandwidth exceeding 200 nm, enabling spectrally separable generation of multi-photon entanglement across the telecom band. The generated photons are encoded in time bins for robust fiber compatibility, and a coherent interface enabling reversible conversion between time-bin and polarization degrees of freedom allows complete quantum state tomography. We measure two-photon entanglement with a brightness of 6.7 MHz/mW/nm and a fidelity of $0.874 \pm 0.002$. At a pump power of 0.08 mW, the four-photon state exhibits a fourfold coincidence rate of 1 Hz and a fidelity of $0.74 \pm 0.01$, representing a threefold improvement over previous integrated platforms. Our results establish LNOI as a scalable platform for broadband multi-photon entanglement and provide a practical route toward dense wavelength-multiplexed quantum networks.

quant-pharXiv:2603.09397•Mar 11, 2026•0 citations

Spectrally multiplexed and ultrabright entangled photon pairs in a lithium niobate microresonator

Boyu Xu, Likun Chen, Jintian Lin +10 more

Abstract On-chip bright quantum sources with multiplexing ability are extremely high in demand for the integrated quantum networks with unprecedented scalability and complexity. Here, we demonstrate an ultrabright and broadband biphoton quantum source generated in a lithium niobate microresonator system. Without introducing the conventional domain poling, the on-chip microdisk produces entangled 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, which can be furthered enlarged. Meanwhile, the generation rate reaches 5.13 MHz/μW with a coincidence-to- accidental ratio up to 804. Besides, the quantum source manifests the prominent purity with heralded single photon correlation g(2)H(0)=0.0098±0.0021 and energy-time entanglement with excellent interference visibility of 96.5%±1.9%.

•Aug 17, 2021•2 citations

On-Chip Quantum Interference between Independent Lithium Niobate-on-Insulator Photon-Pair Sources

Robert J. Chapman, Tristan Kuttner, Jost Kellner +5 more

Generating and interfering nonclassical states of light is fundamental to optical quantum information science and technology. Quantum photonic integrated circuits provide one pathway towards scalability by combining nonlinear sources of nonclassical light and programmable circuits in centimeter-scale devices. The key requirements for quantum applications include efficient generation of indistinguishable photon-pairs and high-visibility programmable quantum interference. Here, we demonstrate a lithium niobate-on-insulator (LNOI) integrated photonic circuit that generates a two-photon path-entangled state, and a programmable interferometer for quantum interference. We generate entangled photons with ∼2.3×10^{8} pairs/s/mW brightness and perform quantum interference experiments on the chip with 96.8±3.6% visibility. LNOI is an emerging photonics technology that has revolutionized high-speed modulators and efficient frequency conversion. Our results provide a path towards large-scale integrated quantum photonics including efficient photon-pair generation and programmable circuits for applications such as boson sampling and quantum communications.

arXiv:2404.08378•Physical Review Letters•May 12, 2025•18 citations

Electrically Pumped Ultrabright Entangled Photons on Chip

Xu-Feng Jiao, Ming-Yang Zheng, Yi-Hang Chen +9 more

Entangled photon sources (EPSs) are essential for quantum science and technology. Despite advancements in integrated optical platforms like thin-film lithium niobate, a scalable, high-performance, chip-scale EPS has remained elusive. We address this by demonstrating an electrically pumped, post-selection-free polarization EPS, achieved through hybrid integration of a distributed feedback laser with a thin-film lithium niobate chip, which integrates periodically poled lithium niobate waveguides, a beam splitter, and a polarization rotator combiner. By injecting current into the chip, we realize a high-performance EPS with a bandwidth of 73 nm and an entanglement pair generation rate of 4.5×10^{10} pairs/s/mW. The polarization entanglement shows Bell-state fidelities above 96% across frequency-correlated modes. This compact, integrated EPS enables key applications, including high-speed quantum key distribution via wavelength division multiplexing, satellite-based quantum communication, and entanglement-based quantum metrology.

arXiv:2508.14566•Physical Review Letters•Oct 27, 2025•3 citations

Programmable Bell state generation in an integrated thin film lithium niobate circuit

Andreas Maeder, Robert J. Chapman, Alessandra Sabatti +3 more

Abstract Entanglement is central to quantum technologies such as cryptography, sensing, and computing. Photon pairs generated via nonlinear optical processes are excellent for preparing entangled states due to their long coherence times and compatibility with fiber optic networks. Steady progress in nanofabrication has positioned lithium niobate-on-insulator (LNOI) as a leading platform for monolithic integration of photon pair sources into optical circuits, leveraging its strong second-order nonlinearity. Here, we present a reconfigurable photonic integrated circuit on LNOI, which combines two on-chip photon pair sources with programmable interferometers, enabling the generation of entangled states. The photon pair sources achieve a source brightness of 26 MHz nm −1 mW −1 while maintaining a coincidence-to-accidental ratio above 100. We successfully interfere the two sources with 99.0 ± 0.7% visibility, demonstrating the indistinguishability required for producing entanglement on-chip. We show the preparation of any of the maximally entangled Bell states with fidelity above 90% verified by quantum state tomography. These results establish LNOI as a compelling, scalable platform to explore integrated quantum photonic technologies enabled by high-brightness sources of entangled quantum states.

arXiv:2506.18079•Light Science & Applications•Jan 3, 2026•6 citations
A high-flux entangled-photon source is a key resource for quantum optical study and application. Here, it is realized in a lithium niobate on isolator (LNOI) chip, with 2.79 \ifmmode\times\else\texttimes\fi{} 1011{10}^{11}1011 Hz/mW photon-pair rate and 1.53 \ifmmode\times\else\texttimes\fi{} 109{10}^{9}109 Hz/(nm mW) spectral brightness. These data are boosted by over 2 orders of magnitude compared with existing technologies. A 160-nm-broad bandwidth is engineered for eight-channel multiplexed energy-time entanglement. Harnessed by high-extinction-frequency correlation and Franson interferences up to 99.17% visibility, such energy-time-entanglement multiplexing further enhances the high-flux data rate and warrants broad application in quantum-information processing on a chip.
On-chip bright quantum sources with multiplexing ability are extremely high in demand for the integrated quantum networks with unprecedented scalability and complexity. Here, we demonstrate an ultrabright and broadband biphoton quantum source generated in a lithium niobate microresonator system.Without introducing the conventional domain poling, the on-chip microdisk produces entangled 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 nm30\ \rm nm30 nm bandwidth limited by the filtering system, which can be furthered enlarged.Meanwhile, the generation rate reaches $5.13\ {\rm MHz}/\upmu \rm W$ with a coincidence-to-accidental ratio up to 804804804.Besides, the quantum source manifests the prominent purity with heralded single photon correlation gH(2)(0)=0.0098±0.0021g_H^{(2)}(0)=0.0098\pm0.0021gH(2)​(0)=0.0098±0.0021 and energy-time entanglement with excellent interference visibility of 96.5%±1.9%96.5\%\pm1.9\%96.5%±1.9%. Such quantum sources at the telecommunication band pave the way for high-dimensional entanglement and future integrated quantum information systems.
Quantum networks based on wavelength-multiplexed entanglement enable parallel distribution of quantum correlations, increasing channel capacity for secure communication and distributed quantum information processing. However, broadband integrated sources capable of generating multipartite entanglement beyond photon pairs remain scarce. Here we report on-chip generation of telecom-band four-photon entanglement in a periodically poled thin-film lithium niobate on insulator (LNOI) waveguide. Type-0 spontaneous parametric down-conversion provides a phase-matching bandwidth exceeding 200 nm, enabling spectrally separable generation of multi-photon entanglement across the telecom band. The generated photons are encoded in time bins for robust fiber compatibility, and a coherent interface enabling reversible conversion between time-bin and polarization degrees of freedom allows complete quantum state tomography. We measure two-photon entanglement with a brightness of 6.7 MHz/mW/nm and a fidelity of 0.874±0.0020.874 \pm 0.0020.874±0.002. At a pump power of 0.08 mW, the four-photon state exhibits a fourfold coincidence rate of 1 Hz and a fidelity of 0.74±0.010.74 \pm 0.010.74±0.01, representing a threefold improvement over previous integrated platforms. Our results establish LNOI as a scalable platform for broadband multi-photon entanglement and provide a practical route toward dense wavelength-multiplexed quantum networks.
Abstract On-chip bright quantum sources with multiplexing ability are extremely high in demand for the integrated quantum networks with unprecedented scalability and complexity. Here, we demonstrate an ultrabright and broadband biphoton quantum source generated in a lithium niobate microresonator system. Without introducing the conventional domain poling, the on-chip microdisk produces entangled 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, which can be furthered enlarged. Meanwhile, the generation rate reaches 5.13 MHz/μW with a coincidence-to- accidental ratio up to 804. Besides, the quantum source manifests the prominent purity with heralded single photon correlation g(2)H(0)=0.0098±0.0021 and energy-time entanglement with excellent interference visibility of 96.5%±1.9%.
Generating and interfering nonclassical states of light is fundamental to optical quantum information science and technology. Quantum photonic integrated circuits provide one pathway towards scalability by combining nonlinear sources of nonclassical light and programmable circuits in centimeter-scale devices. The key requirements for quantum applications include efficient generation of indistinguishable photon-pairs and high-visibility programmable quantum interference. Here, we demonstrate a lithium niobate-on-insulator (LNOI) integrated photonic circuit that generates a two-photon path-entangled state, and a programmable interferometer for quantum interference. We generate entangled photons with ∼2.3×10^{8} pairs/s/mW brightness and perform quantum interference experiments on the chip with 96.8±3.6% visibility. LNOI is an emerging photonics technology that has revolutionized high-speed modulators and efficient frequency conversion. Our results provide a path towards large-scale integrated quantum photonics including efficient photon-pair generation and programmable circuits for applications such as boson sampling and quantum communications.
Entangled photon sources (EPSs) are essential for quantum science and technology. Despite advancements in integrated optical platforms like thin-film lithium niobate, a scalable, high-performance, chip-scale EPS has remained elusive. We address this by demonstrating an electrically pumped, post-selection-free polarization EPS, achieved through hybrid integration of a distributed feedback laser with a thin-film lithium niobate chip, which integrates periodically poled lithium niobate waveguides, a beam splitter, and a polarization rotator combiner. By injecting current into the chip, we realize a high-performance EPS with a bandwidth of 73 nm and an entanglement pair generation rate of 4.5×10^{10} pairs/s/mW. The polarization entanglement shows Bell-state fidelities above 96% across frequency-correlated modes. This compact, integrated EPS enables key applications, including high-speed quantum key distribution via wavelength division multiplexing, satellite-based quantum communication, and entanglement-based quantum metrology.
Abstract Entanglement is central to quantum technologies such as cryptography, sensing, and computing. Photon pairs generated via nonlinear optical processes are excellent for preparing entangled states due to their long coherence times and compatibility with fiber optic networks. Steady progress in nanofabrication has positioned lithium niobate-on-insulator (LNOI) as a leading platform for monolithic integration of photon pair sources into optical circuits, leveraging its strong second-order nonlinearity. Here, we present a reconfigurable photonic integrated circuit on LNOI, which combines two on-chip photon pair sources with programmable interferometers, enabling the generation of entangled states. The photon pair sources achieve a source brightness of 26 MHz nm −1 mW −1 while maintaining a coincidence-to-accidental ratio above 100. We successfully interfere the two sources with 99.0 ± 0.7% visibility, demonstrating the indistinguishability required for producing entanglement on-chip. We show the preparation of any of the maximally entangled Bell states with fidelity above 90% verified by quantum state tomography. These results establish LNOI as a compelling, scalable platform to explore integrated quantum photonic technologies enabled by high-brightness sources of entangled quantum states.