Generation of correlated photons in hydrogenated amorphous-silicon   waveguides
  We report the first (to our knowledge) observation of correlated photon emission in hydrogenated amorphous- silicon waveguides. We compare this to photon generation in crystalline silicon waveguides with the same geome- try. In particular, we show that amorphous silicon has a higher nonlinearity and competes with crystalline silicon in spite of higher loss. 
S. Clemmen, A. Perret, S. K. Selvaraja, W. Bogaerts, D. van Thourhout,   R. Baets, Ph. Emplit, and S. Massar
quant-ph physics.optics