A single-photon source based on the stimulated four-wave mixing (SFWM) process in optical bers is presented.
At the output of the source, the state of polarization (SOP) of the photons can be adjusted in order to obtain
any linear polarization. A theoretical model to describe the average photon counts recorded in the avalanche
photodiodes (APDs) is presented. The experimental results show an accurate detection of two non-orthogonal
linear SOPs after propagation through a 60 km quantum channel, and good agreement with theory. This source,
operating in a low power regime, can be used for quantum key distribution (QKD) using polarization-encoding
in quantum communications.