A quantum communication apparatus is used in operations to generate
entanglement between the two physical system ensembles and operations to
extend the distance between entangled ensembles by connecting pairs of
entangled ensembles. The apparatus uses only passive elements without any
actuating parts, active devices having no mechanically actuating parts,
such as an electro-optical device capable of ultrahigh-speed operation,
and a laser source capable of generating high-speed pulse trains or a
continuous wave laser source. The apparatus can rapidly execute light
irradiation necessary for entanglement generation and connection, and
detection of a generated photon at the needed sites within a decoherence
time of the physical system.