Entangled coherent states created by mixing squeezed vacuum and coherent light

Entangled coherent states are a fundamentally interesting class of quantum states of light, with important implications in quantum information processing, for which robust schemes to generate them are required. Here, we show that entangled coherent states emerge, with high fidelity, when mixing coherent and squeezed vacuum states of light on a beam splitter. These maximally entangled states, where photons bunch at the exit of a beam splitter, are measured experimentally by Fock-state projections. Entanglement is examined theoretically using a Bell-type nonlocality test and compared with ideal entangled coherent states. We experimentally show nearly perfect similarity with entangled coherent states for an optimal ratio of coherent and squeezed vacuum light. In our scheme, entangled coherent states are generated deterministically with small amplitudes, which could be beneficial, for example, in deterministic distribution of entanglement over long distances.