Quantum cloning with an optical fiber amplifier
  It has been shown theoretically that a light amplifier working on the physical principle of stimulated emission should achieve optimal quantum cloning of the polarization state of light. We demonstrate close-to-optimal universal quantum cloning of polarization in a standard fiber amplifier for telecom wavelengths. For cloning 1 --> 2 we find a fidelity of 0.82, the optimal value being 5/6 = 0.83. 
Sylvain Fasel, Nicolas Gisin, Gregoire Ribordy, Valerio Scarani, Hugo   Zbinden