  We demonstrate the multiplexing of a classical coherent and a quantum state
of light in a single telecommunciation fiber. For this purpose we make use of
spontaneous parametric down conversion and quantum frequency conversion to
generate photon pairs at 854 nm and the telecom O-band. The herald photon
triggers a telecom C-band laser pulse. The telecom single photon and the laser
pulse are combined and coupled to a standard telecom fiber. Low background time
correlation of the classical and quantum signal behind the fiber shows
successful telecommunication channel multiplexing.
