Patent ID: 8244082

Claim:
A device for generating polarization-entangled photons from pump photons by parametric down-conversion, comprising: a substrate; a waveguide structure formed in said substrate, said waveguide structure including a first and a second waveguide, and being comprised of an optically non-linear material with periodically poled substrate areas; a beam splitter receiving said pump photons and arranged to supply a portion of pump photons to said first wave-guide and a residual portion of pump photons to said second waveguide during operation of said device; said pump photons degenerating to vertically polarized signal and idler photons in one of said first and said second wave-guides, and to horizontally polarized signal and idler photons in said other one of said first and said second waveguides; a unifying path provided downstream of said first and second waveguides, and arranged to receive and conduct both the signal photons and the idler photons; spectral separating means provided downstream of said unifying path and arranged for spectral separation of said signal photons and said idler photons and providing them at separate outputs, at least one of thermal and electrooptical tuning means associated to at least said second one of said first and said second optical waveguides for fine-tuning wavelength ratios during said down-conversion; and electrooptical means associated to at least said first one of said first and said second waveguides for adjusting the phase relationship between said horizontally polarized photon states and said vertically polarized photon states prevailing at said outputs of said separating means.