Quantumkey distribution (QKD) promises unconditional security for communication. However, the random choices of the measurement basis in QKD usually result in low key creation efficiency. This drawback is overcome in the differential-phase-shift QKD, provided that each photon can be prepared in a large number of time bins with a proper waveform. In this work we develop a miniature 1550-nm single-photon source to generate narrowband single photon in 50 time bins with a nearly optimal waveform for achieving unity key creation efficiency. By utilizing these single photons in the field test, we demonstrate the differential-phase-shift QKD with a key creation efficiency of 97%. Our work shows that the practical QKD can benefit from the narrowband single photons with controllable waveforms.
@article{arxiv.2406.07786,
title = {Field Test of Quantum Key Distribution with High Key Creation Efficiency},
author = {Yung-Cheng Kao and Sheng-Hsuan Huang and Chin-Hsuan Chang and Chih-Hsiang Wu and Shih-Hsien Chu and Jian Jiang and An-Chi Zhang and Sheng-Yao Huang and Jhih-Heng Yan and Kai-Ming Feng and Chih-Sung Chuu},
journal= {arXiv preprint arXiv:2406.07786},
year = {2024}
}