Amplification of optical Schrodinger cat states with an implementation protocol based on a frequency comb

We proposed and analyzed a scheme to generate large-size Schr??dinger cat states based on linear operations of Fock states, squeezed vacuum states, and conditional measurements. By conducting conditional measurements via photon number detectors, two unbalanced small-amplitude Schr??dinger kitten states combined by a beam splitter can be amplified to a large-size cat state with the same parity. According to simulation results, two Schr??dinger odd kitten states with amplitudes of |??| = 1.06 and |??| = 1.11 generated from one-photonsubtracted 3 dB squeezed vacuum states, are amplified to an odd cat state of |??| = 1.73 with a fidelity of F = 99%. A large-size Schr??dinger odd cat state with |??| = 2.51 and F = 97.30% is predicted when 5.91 dB squeezed vacuum states are employed. According to the analysis on the impacts of experimental imperfections in practice, Schr??dinger odd cat states of |??| > 2 are available. A feasible configuration based on a quantum frequency comb is developed to realize the large-size cat state generation scheme we proposed.