Practical limitations in optical entanglement purification
  Entanglement purification protocols play an important role in the distribution of entangled systems, which is necessary for various quantum information processing applications. We consider the effects of photo-detector efficiency and bandwidth, channel loss and mode-mismatch on the operation of an optical entanglement purification protocol. We derive necessary detector and mode-matching requirements to facilitate practical operation of such a scheme, without having to resort to destructive coincidence type demonstrations. 
Peter P. Rohde, Timothy C. Ralph, William J. Munro