Generation of macroscopic superposition states with small nonlinearity
  We suggest a scheme to generate a macroscopic superposition state (Schrodinger cat state) of a free-propagating optical field using a beam splitter, homodyne measurement and a very small Kerr nonlinear effect. Our scheme makes it possible to considerably reduce the required nonlinear effect to generate an optical cat state using simple and efficient optical elements. 
H. Jeong, M.S. Kim, T.C. Ralph and B.S. Ham