ABSTRACT
Photons are ideal carriers to transmit quantum information over large dis-
tances due to their low interaction with the environment. In 1984, Ben-
nett and Brassard proposed a secret key-distribution protocol [1] that uses
the single-particle character of a photon to avoid any possibility of eaves-
dropping on an encoded message (for a review see [2]). Also, the imple-
mentation of efficient quantum gates based on photons and linear optics
was proposed [3, 4] and demonstrated [5, 6]. Besides, photons have been
proposed as information carriers in larger networks [7] between processing
nodes of stationary qubits, like ions [8-11], atoms [12, 13], quantum dots
(QDs) [14, 15], and Josephson qubits [16, 17].