  Realistic linear quantum information processing necessitates the ability to
synchronously generate entangled photon pairs either at the same or at distant
locations. Here, we report the experimental realization of synchronized
generation of independent entangled photon pairs. The quality of
synchronization is confirmed by observing a violation of Bell's inequality with
3.2 standard deviations in an entanglement swapping experiment. The techniques
developed in our experiment will be of great importance for future linear
optical realization of quantum repeaters and quantum computation.
