Universal optical amplification without nonlinearity
  We propose and experimentally realize a new scheme for universal phase-insensitive optical amplification. The presented scheme relies only on linear optics and homodyne detection, thus circumventing the need for nonlinear interaction between a pump field and the signal field. The amplifier demonstrates near optimal quantum noise limited performance for a wide range of amplification factors. 
V. Josse, M. Sabuncu, N. J. Cerf, G. Leuchs, U. L. Andersen