Generating Optical Schrödinger Kittens for Quantum Information Processing

We present a detailed experimental analysis of a free-propagating light pulse prepared in a ``Schrödinger kitten'' state, which is defined as a quantum superposition of ``classical'' coherent states with small amplitudes. This kitten state is generated by subtracting one photon from a squeezed vacuum beam, and it clearly presents a negative Wigner function. The predicted influence of the experimental parameters is in excellent agreement with the experimental results. The amplitude of the coherent states can be amplified to transform our ``Schrödinger kittens'' into bigger Schrödinger cats, providing an essential tool for quantum information processing.