Producing a delocalized frequency-time Schrödinger-cat-like state with Hong-Ou-Mandel interferometry

In the late 1980's, Ou and Mandel experimentally observed signal beatings by performing a non-time-resolved coincidence detection of two photons having interfered in a balanced beam splitter [Phys. Rev. Lett 61, 54 (1988)10.1103/PhysRevLett.61.54]. In this work, we provide an alternative interpretation of the fringe pattern observed in this experiment as the direct measurement of the chronocyclic Wigner distribution of a frequency Schrödinger-cat-like state produced by local spectral filtering. Based on this analysis, we also study the time-resolved HOM experiment to measure such frequency state.