Multiphoton path entanglement by non-local bunching
  Multiphoton path entanglement is created without applying post-selection, by manipulating the state of stimulated parametric down-conversion. A specific measurement on one of the two output spatial modes leads to the non-local bunching of the photons of the other mode, forming the desired multiphoton path entangled state. We present experimental results for the case of a heralded two-photon path entangled state and show how to extend this scheme to higher photon numbers. 
H. S. Eisenberg, J. F. Hodelin, G. Khoury, D. Bouwmeester