Degenerate Parametric down-conversion at 1570 nm by periodically poled lithium niobate waveguide: a route to single photon source and photon entanglement

摘要

In this paper we measure the efficiency of photon pair production from parametric downconversion at the photon counting level, generated in a laboratory prototype of PPLN waveguide at 1572 nm. The aim is to enhance the brightness of an heralded single photon source and to improve compactness for quantum communication applications, namely quantum key distribution. We observed a maximum of the conversion efficiency corresponding to 7.9 10~6 photon pairs/s for a pump power of 28 μW. This value is compared with the measured pairs production in a classical experiment of difference frequency generation, realized with the same sample by analogue classical detection. We highlight the advantages of using the waveguide versus a bulk PPLN for such applications and we foresee further possible improvements by adopting waveguide in a single photon level experimental setup.