Multiphoton interference outperforms pairwise overlaps for distinguishability characterization

Abstract

We propose a protocol that characterizes the pairwise overlaps of the internal modes of single photons more efficiently than pairwise Hong-Ou-Mandel characterization experiments. This protocol exploits multiphoton interference. We experimentally implement this protocol to characterize three photons. We show that our implementation of the characterization protocol outperforms the pairwise Hong-Ou-Mandel characterization, even if the Hong-Ou-Mandel characterization would have been performed in a noiseless, perfect experiment. We demonstrate this via the Fisher information matrix.