Entanglement measurement based on two-particle interference
  We propose a simple and realizable method using a two-particle interferometer for the experimental measurement of pairwise entanglement, assuming some prior knowledge about the quantum state. The basic idea is that the properties of the density matrix can be revealed by the single- and two-particle interference patterns. The scheme can easily be implemented with polarized entangled photons. 
Jian-Ming Cai, Zheng-Wei Zhou, Guang-Can Guo