Can Hong-Ou-Mandel type quantum correlation be a test tool for quantum entanglement?

Quantum technologies based on the particle nature of a photon has been progressed over the last several decades, where the fundamental quantum feature of entanglement has been tested by Hong-Ou-Mandel (HOM) type anticorrelation as well as Bell-type nonlocal correlation. Mutually exclusive quantum natures of the wave-particle duality of a single photon have been intensively investigated to understand the fundamental physics of mysterious quantum nature. Here, we revisit the HOM-type quantum correlation to answer the question whether the HOM-type anticorrelation can be a test tool for quantum entanglement. For this, a pair of spontaneous parametric down converted photons is tested for the anticorrelation of HOM effects, where the SPDC-generated photon pair is not in an entangled state.
Comment: 5 pages, 1 figure