  The state obtained when a single photon impinges on a balanced beamsplitter
is often known as single-photon entangled and its nonlocal properties have been
the subject of intense debates in the quantum optics and foundations
communities. It is however clear that a standard Bell test made only of passive
optical elements cannot reveal the nonlocality of this state. We show that the
nonlocality of single-photon entangled states can nevertheless be revealed in a
quantum network made only of beamsplitters and photodetectors. In our protocol,
three single-photon entangled states are distributed in a triangle network,
introducing indeterminacy in the photons' paths and creating nonlocal
correlations without the need for measurements choices. We discuss a concrete
experimental realisation and provide numerical evidence of the tolerance of our
protocol to standard noise sources. Our results show that single-photon
entanglement may constitute a promising solution to generate genuine
network-nonlocal correlations useful for Bell-based quantum information
protocols.
