Entanglement of coherent states and decoherence

The possibility of producing entangled superpositions of strong coherent st ates is discussed. A recent proposal by Howell and Yeazell (2000 Phys. Rev: A 62 012102) of a device that entangles two strong coherent states is modi fied. It is shown that the modified scheme can generate non-classical state s that violate Bell inequality. Moreover, a detailed analysis of the effect of losses and decoherence on the degree of entanglement is accomplished. I t reveals the high sensitivity of the device to any disturbances and the fr agility of generated states.