Bell state analyzer (BSA) is one of the most crucial apparatus in photonic quantum information processing. While linear optics provide a practical way to implement BSA, it provides unavoidable errors when inputs are not ideal single-photon states. Here, we propose a simple method to deduce the BSA for single-photon inputs using weak coherent pulses. By applying the method to Reference-Frame-Independent Measurement-Device-Independent Quantum Key Distribution, we experimentally verify the feasibility and effectiveness of the method.
@article{arxiv.2009.08584,
title = {Characterizing Bell state analyzer using weak coherent pulses},
author = {Donghwa Lee and Young-Wook Cho and Hyang-Tag Lim Sang-Wook Han and Hojoong Jung and Sung Moon and Yong-Su Kim},
journal= {arXiv preprint arXiv:2009.08584},
year = {2020}
}