中国物理B ›› 2023, Vol. 32 ›› Issue (8): 80308-080308.doi: 10.1088/1674-1056/acd8b3

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Degenerate polarization entangled photon source based on a single Ti-diffusion lithium niobate waveguide in a polarization Sagnac interferometer

Yu Sun(孙宇)1, Chang-Wei Sun(孙昌伟)2, Wei Zhou(周唯)1, Ran Yang(杨然)1, Jia-Chen Duan(端家晨)1, Yan-Xiao Gong(龚彦晓)1, Ping Xu(徐平)3,†, and Shi-Ning Zhu(祝世宁)1   

  1. 1. National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China;
    2. NanZhi Institude of Advanced Optoelectronic Integration, Nanjing 210018, China;
    3. Institute for Quantum Information and State Key Laboratory of High Performance Computing, College of Computer Science and Technology, National University of Defense Technology, Changsha 410073, China
  • 收稿日期:2023-05-11 修回日期:2023-05-11 接受日期:2023-05-25 发布日期:2023-07-27
  • 通讯作者: Ping Xu E-mail:pingxu520@nju.edu.cn
  • 基金资助:
    Project supported by the National Key R&D Program of China (Grant Nos.2022YFF0712800 and 2019YFA0308700).

Degenerate polarization entangled photon source based on a single Ti-diffusion lithium niobate waveguide in a polarization Sagnac interferometer

Yu Sun(孙宇)1, Chang-Wei Sun(孙昌伟)2, Wei Zhou(周唯)1, Ran Yang(杨然)1, Jia-Chen Duan(端家晨)1, Yan-Xiao Gong(龚彦晓)1, Ping Xu(徐平)3,†, and Shi-Ning Zhu(祝世宁)1   

  1. 1. National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China;
    2. NanZhi Institude of Advanced Optoelectronic Integration, Nanjing 210018, China;
    3. Institute for Quantum Information and State Key Laboratory of High Performance Computing, College of Computer Science and Technology, National University of Defense Technology, Changsha 410073, China
  • Received:2023-05-11 Revised:2023-05-11 Accepted:2023-05-25 Published:2023-07-27
  • Contact: Ping Xu E-mail:pingxu520@nju.edu.cn
  • Supported by:
    Project supported by the National Key R&D Program of China (Grant Nos.2022YFF0712800 and 2019YFA0308700).

摘要: 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)×106 pairs/(s· nm·mW). 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.

关键词: polarization entanglement source, Sagnac interferometer, quantum information, lithium niobate waveguide

Abstract: 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)×106 pairs/(s· nm·mW). 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.

Key words: polarization entanglement source, Sagnac interferometer, quantum information, lithium niobate waveguide

中图分类号:  (Entanglement and quantum nonlocality)

  • 03.65.Ud
03.67.-a (Quantum information) 42.50.Dv (Quantum state engineering and measurements) 42.65.-k (Nonlinear optics)