Silicon photonics-integrated time-domain balanced homodyne detector for quantum tomography and quantum key distribution
Yan-Xiang Jia, Xuyang Wang, Xiao Hu, Xin Hua, Yu Zhang, Xubo Guo, Shengxiang Zhang, Xi Xiao, Shaohua Yu, Jun Zou, Yongmin Li
Abstract
Abstract 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.