  In this work, we investigate the controlled teleportation protocol using
optical qubits within the single-rail logic. The protocol makes use of an
entangled tripartite state shared by the controller and two further parties
(users) who will perform standard teleportation. The goal of the protocol is to
guarantee that the teleportation is successful only with the permission of the
controller. Optical qubits based on either superpositions of vacuum and
single-photon states or superposition of coherent states are employed here to
encode a tripartite maximal slice state upon which the protocol is based. We
compare the performances of these two encodings under losses which are present
when the qubits are guided through an optical fiber to the users. Finally, we
investigate the non-locality of the shared tripartite state to see whether or
not it impacts the efficiency of the protocol.
