Heralded single photons (HSPs) generated by spontaneous parametric down-conversion (SPDC) are useful resource to achieve various photonic quantum information processing. Given a large-scale experiment which needs multiple HSPs, increasing the generation rate with suppressing higher-order pair creation is desirable. One of the promising ways is to use a pump laser with a GHz-order repetition rate. In such a high repetition rate regime, however, single-photon detectors can only partially identify the pulses. Hence, we develop a simple model to consider that effect on the spectral purity, and experimentally demonstrate a high-visibility Hong-Ou-Mandel interference between two independent HSPs generated by SPDC with 3.2 GHz-repetition-rate mode-locked pump pulses. The observed visibility of 0.88(3) is in good agreement with our theoretical model.
@article{arxiv.2009.00255,
title = {Ultra-fast Hong-Ou-Mandel interferometry via temporal filtering},
author = {Yoshiaki Tsujimoto and Kentaro Wakui and Mikio Fujiwara and Masahide Sasaki and Masahiro Takeoka},
journal= {arXiv preprint arXiv:2009.00255},
year = {2021}
}