  Entanglement is a unique property of quantum systems and an essential
resource for many quantum technologies. The ability to transfer or swap
entanglement between systems is an important protocol in quantum information
science. Entanglement between photons forms the basis of distributed quantum
networks and the demonstration of photonic entanglement swapping is essential
for their realization. Here an experiment demonstrating entanglement swapping
from two independent multimode time-frequency entangled sources is presented,
resulting in multiple heralded temporal-mode Bell states. Entanglement in the
heralded states is verified by measuring conditional anti-correlated joint
spectra as well as quantum beating in two-photon interference. Our
proof-of-concept experiment is able to distinguish up to five orthogonal Bell
pairs within the same setup, limited in principle only by the entanglement of
the sources.
