New Journal of Physics (Jan 2023)

Silicon photonics-integrated time-domain balanced homodyne detector for quantum tomography and quantum key distribution

  • Yanxiang Jia,
  • Xuyang Wang,
  • Xiao Hu,
  • Xin Hua,
  • Yu Zhang,
  • Xubo Guo,
  • Shengxiang Zhang,
  • Xi Xiao,
  • Shaohua Yu,
  • Jun Zou,
  • Yongmin Li

DOI
https://doi.org/10.1088/1367-2630/acfcd4
Journal volume & issue
Vol. 25, no. 10
p. 103030

Abstract

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We designed and experimentally demonstrated a silicon photonics-integrated time-domain balanced homodyne detector (TBHD), containing an optical part of dimensions of 1.5 mm × 0.4 mm. To automatically and accurately balance the detector, new variable optical attenuators were used, and a common mode rejection ratio of 86.9 dB could be achieved. In the quantum tomography experiment, the density matrix and Wigner function of a coherent state were reconstructed with 99.97% fidelity. The feasibility of this TBHD in a continuous-variable quantum key distribution (CVQKD) system was also demonstrated. Our TBHD technologies are expected to be used in silicon photonics-integrated CVQKD system and silicon photonics-integrated BB84 heterodyne system.

Keywords