We present an efficient tool capable of measuring the spectral correlations between photons emerging from a Hong-Ou-Mandel interferometer. We show that for our spectrally factorizable spontaneous downconversion source the Hong-Ou-Mandel interference visibility decreases as the photons frequency spread is increased to a maximum of 165 nm. Unfiltered, we obtained a visibility of 92.0±0.2%. The maximum visibility was 97±0.2% after applying filtering. We show that the tool can be useful for the study of spectral correlations that impair high-visibility and high-fidelity multi-source interference applications.
@article{arxiv.1409.1616,
title = {Spectral Correlation Measurements at the Hong-Ou-Mandel Interference Dip},
author = {Thomas Gerrits and Francesco Marsili and Varun Verma and Lynden Shalm and Matthew Shaw and Richard Mirin and Sae Woo Nam},
journal= {arXiv preprint arXiv:1409.1616},
year = {2015}
}