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

Chinese Optics Letters

Multichannel polarization-entangled photon-pair source for entanglement distribution

Mengning Hu Mengning Hu, Yuping Chen, Guangzhen Li, and Xianfeng Chen and Xianfeng Chen

Published Jan 1, 2016• 1 citation
Publisher

Abstract

A multichannel polarization-entangled photon-pair source in an MgO-doped periodically poled lithium niobate (MgO:PPLN) waveguide is proposed. Based on type I quasi-phase-matched spontaneous parametric down conversion in a single MgO: PPLN waveguide placed inside a Sagnac interferometer and pumped by monochromatic light, a source capable of supporting tens to hundreds of channels of polarization-entangled photon pairs in fiber communication bands simultaneously can be achieved. An inherent channel switch of this source is investigated, which will be significant for future entanglement distribution networks.

DOI
10.3788/col201614.061301

Related papers

Prediction of multichannel polarization-entangled photon pairs in a single periodically poled lithium niobate with a monochromatic pump

Shiming Gao, Changxi Yang

A method is presented for the first time to our knowledge for generating multiple-channel polarization-entangled photon pairs simultaneously based on type II quasi-phase-matched spontaneous parametric downconversion pumped by monochromatic light in a single periodically poled lithium niobate (PPLN) crystal. The expression for the count of the polarization-entangled photon pairs is analytically obtained. It is predicted that one-, two-, and even three-channel polarization-entangled photon pairs can be simultaneously generated just by suitably choosing the PPLN grating period and the pump frequency.

Optics Letters•Sep 4, 2007•6 citations

A method for generating multichannel entangled photon pairs

Peng Yu, Qingping Shi, Wei Li

A method is presented for generating multiple-channel color-entangled photon pairs simultaneously based on type I quasi-phase-matched spontaneous parametric downconversion pumped in a single periodically poled lithium niobate (PPLN) crystal. It is predicted that one-, and two-channel color-entangled photon pairs can be simultaneously generated just by suitably choosing the PPLN grating period and the pump frequency. We point out that the full width at half maximum (FWHM) of idler and signal light are broadened dramatically due to spontaneous parametric downconversion in case of a pulsed pump. Then this method is applied for generating multiple-channel polarization-entangled photon pairs simultaneously based on type II quasiphase- matched spontaneous parametric downconversion.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Feb 19, 2015•0 citations

Telecom source of tunable polarization-entanglement distribution up to 100-km for multi-user QKD over metro-area fiber-optic networks

Vikash Kumar Yadav, Vivek Venkataraman, Joyee Ghosh

The scalability of quantum communication networks requires compact, fiber-integrated, easy-to-deploy, and efficient wavelength-division-multiplexed (WDM) sources for multi-user secure key distribution. Here, we demonstrate such a multi-channel source of polarization-entangled photon pairs in the low-loss telecom C-band based on type-0 spontaneous parametric downconversion in a fiber-coupled Zn-indiffused MgO-doped periodically poled lithium-niobate (MgO:PPLN) ridge waveguide in the Sagnac configuration. The source can be easily tuned to generate the |Φ+⟩ or |Φ−⟩ Bell state in 14 channel pairs of the International Telecommunication Union dense WDM (100-GHz spacing) grid around 1550-nm with a raw fidelity of ≳89%, with a maximum value of ≳94%. The raw concurrence is ≳0.8 for both Bell states in all channel pairs, and the observed S-parameter (>2.56 ± 0.04 in all 14-channel pairs) shows a strong violation of CHSH-Bell’s inequality. The source’s suitability for long-distance entanglement transmission is also demonstrated by the successful transfer of entangled photons up to 100 km while maintaining fidelity >85% and quantum bit error rate <9%. The effect of polarization mode dispersion on entanglement distribution among remote users is also studied in detail. All these performance metrics are measured using conventional room-temperature semiconductor-based single-photon avalanche detectors, and these are the best reported with these detectors. Our highly flexible source can support up to ∼40 user pairs to communicate simultaneously, and it can be easily deployed into the current metro-area fiber-optic telecom infrastructure to form a complete WDM-based quantum communication network.

APL Quantum•Jan 6, 2025•2 citations

High-brightness fiber-based Sagnac source of entangled photon pairs for multiplexed quantum networks

Tess Troisi, Yoann Pelet, Romain Dalidet +4 more

A fully fibered source of entangled photon pairs based on a nonlinear Sagnac interferometer is reported. Operating at telecom wavelengths, the source relies exclusively on standard fiber-optic components and periodically poled lithium niobate (PPLN) waveguides, resulting in a compact, robust, and field-deployable architecture. The generation stage supports both polarization and energy-time entanglement without modification, enabling versatile operation depending on the targeted application. Broadband spontaneous parametric down-conversion allows dense wavelength-division multiplexing over the telecom C and L bands. High normalized brightness (10.3 kpairs/s/nm/mW$^2$) is achieved on a standard 100 GHz ITU channel pair, together with high entanglement quality. Polarization and energy-time encodings are characterized through state tomography and two-photon interference measurements, yielding fidelities, purities, and visibilities exceeding 96 % over multiple wavelength channels. The stability and reproducibility of the source are further evaluated through long-duration operation in a network environment. These results demonstrate that the proposed Sagnac source constitutes a practical and scalable building block for future plug-and-play quantum communication and quantum networking platforms.

quant-pharXiv:2602.08863•Feb 10, 2026•0 citations

Pulsed Sagnac source of polarization-entangled photon pairs in telecommunication band

Heonoh Kim, Osung Kwon, Han Seb Moon

We report a source of polarization-entangled photon pairs in the 1550-nm telecommunication band, which is based on non-collinear spontaneous parametric down-conversion in a periodically poled lithium niobate crystal pumped by picosecond pulses. This source is realized utilizing a polarization-based Sagnac interferometer employing a type-0 non-collinear quasi-phase-matching configuration. Polarization entanglement is verified through measurement of the polarization-correlation interference fringes with visibility >96% and by testing the experimental violation of the Clauser-Horne-Shimony-Holt (CHSH) form of Bell's inequality. The CHSH-Bell parameter S is found to be 2.72 ± 0.04, with 18 standard deviations from the statistical uncertainty.

arXiv:1904.00164•Scientific Reports•Mar 22, 2019•26 citations

Generation of multichannel color-entangled photon pairs via type-I spontaneous parametric downconversion

Peng Yu, Wei Li

A method is presented for generating multiple-channel color-entangled photon pairs simultaneously based on type I quasi-phase-matched spontaneous parametric downconversion pumped in a single periodically poled lithium niobate (PPLN) crystal. It is predicted that one-, and two-channel color-entangled photon pairs can be simultaneously generated just by suitably choosing the PPLN grating period and the pump frequency. We point out that the full width at half maximum (FWHM) of idler and signal light are broadened dramatically due to spontaneous parametric downconversion in case of a pulsed pump.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Aug 21, 2014•0 citations
A multichannel polarization-entangled photon-pair source in an MgO-doped periodically poled lithium niobate (MgO:PPLN) waveguide is proposed. Based on type I quasi-phase-matched spontaneous parametric down conversion in a single MgO: PPLN waveguide placed inside a Sagnac interferometer and pumped by monochromatic light, a source capable of supporting tens to hundreds of channels of polarization-entangled photon pairs in fiber communication bands simultaneously can be achieved. An inherent channel switch of this source is investigated, which will be significant for future entanglement distribution networks.
A method is presented for the first time to our knowledge for generating multiple-channel polarization-entangled photon pairs simultaneously based on type II quasi-phase-matched spontaneous parametric downconversion pumped by monochromatic light in a single periodically poled lithium niobate (PPLN) crystal. The expression for the count of the polarization-entangled photon pairs is analytically obtained. It is predicted that one-, two-, and even three-channel polarization-entangled photon pairs can be simultaneously generated just by suitably choosing the PPLN grating period and the pump frequency.
A method is presented for generating multiple-channel color-entangled photon pairs simultaneously based on type I quasi-phase-matched spontaneous parametric downconversion pumped in a single periodically poled lithium niobate (PPLN) crystal. It is predicted that one-, and two-channel color-entangled photon pairs can be simultaneously generated just by suitably choosing the PPLN grating period and the pump frequency. We point out that the full width at half maximum (FWHM) of idler and signal light are broadened dramatically due to spontaneous parametric downconversion in case of a pulsed pump. Then this method is applied for generating multiple-channel polarization-entangled photon pairs simultaneously based on type II quasiphase- matched spontaneous parametric downconversion.
The scalability of quantum communication networks requires compact, fiber-integrated, easy-to-deploy, and efficient wavelength-division-multiplexed (WDM) sources for multi-user secure key distribution. Here, we demonstrate such a multi-channel source of polarization-entangled photon pairs in the low-loss telecom C-band based on type-0 spontaneous parametric downconversion in a fiber-coupled Zn-indiffused MgO-doped periodically poled lithium-niobate (MgO:PPLN) ridge waveguide in the Sagnac configuration. The source can be easily tuned to generate the |Φ+⟩ or |Φ−⟩ Bell state in 14 channel pairs of the International Telecommunication Union dense WDM (100-GHz spacing) grid around 1550-nm with a raw fidelity of ≳89%, with a maximum value of ≳94%. The raw concurrence is ≳0.8 for both Bell states in all channel pairs, and the observed S-parameter (>2.56 ± 0.04 in all 14-channel pairs) shows a strong violation of CHSH-Bell’s inequality. The source’s suitability for long-distance entanglement transmission is also demonstrated by the successful transfer of entangled photons up to 100 km while maintaining fidelity >85% and quantum bit error rate <9%. The effect of polarization mode dispersion on entanglement distribution among remote users is also studied in detail. All these performance metrics are measured using conventional room-temperature semiconductor-based single-photon avalanche detectors, and these are the best reported with these detectors. Our highly flexible source can support up to ∼40 user pairs to communicate simultaneously, and it can be easily deployed into the current metro-area fiber-optic telecom infrastructure to form a complete WDM-based quantum communication network.
A fully fibered source of entangled photon pairs based on a nonlinear Sagnac interferometer is reported. Operating at telecom wavelengths, the source relies exclusively on standard fiber-optic components and periodically poled lithium niobate (PPLN) waveguides, resulting in a compact, robust, and field-deployable architecture. The generation stage supports both polarization and energy-time entanglement without modification, enabling versatile operation depending on the targeted application. Broadband spontaneous parametric down-conversion allows dense wavelength-division multiplexing over the telecom C and L bands. High normalized brightness (10.3 kpairs/s/nm/mW2^22) is achieved on a standard 100 GHz ITU channel pair, together with high entanglement quality. Polarization and energy-time encodings are characterized through state tomography and two-photon interference measurements, yielding fidelities, purities, and visibilities exceeding 96 % over multiple wavelength channels. The stability and reproducibility of the source are further evaluated through long-duration operation in a network environment. These results demonstrate that the proposed Sagnac source constitutes a practical and scalable building block for future plug-and-play quantum communication and quantum networking platforms.
We report a source of polarization-entangled photon pairs in the 1550-nm telecommunication band, which is based on non-collinear spontaneous parametric down-conversion in a periodically poled lithium niobate crystal pumped by picosecond pulses. This source is realized utilizing a polarization-based Sagnac interferometer employing a type-0 non-collinear quasi-phase-matching configuration. Polarization entanglement is verified through measurement of the polarization-correlation interference fringes with visibility >96% and by testing the experimental violation of the Clauser-Horne-Shimony-Holt (CHSH) form of Bell's inequality. The CHSH-Bell parameter S is found to be 2.72 ± 0.04, with 18 standard deviations from the statistical uncertainty.
A method is presented for generating multiple-channel color-entangled photon pairs simultaneously based on type I quasi-phase-matched spontaneous parametric downconversion pumped in a single periodically poled lithium niobate (PPLN) crystal. It is predicted that one-, and two-channel color-entangled photon pairs can be simultaneously generated just by suitably choosing the PPLN grating period and the pump frequency. We point out that the full width at half maximum (FWHM) of idler and signal light are broadened dramatically due to spontaneous parametric downconversion in case of a pulsed pump.