Entanglement properties of optical coherent states under amplitude damping

Through concurrence, we characterize the entanglement of optical coherent‐state qubits subject to an amplitude damping channel. We investigate the distillation capabilities of known error correcting codes and obtain upper bounds on the entanglement depending on the non‐orthogonality of the input states and the channel damping parameter, thus quantitatively analysing these photon‐loss codes which are naturally reminiscent of the standard qubit codes against Pauli errors.