Polarisation-entangled photon-pair source at 1550 nm using 1 mm-long PPLN waveguide in fibre-loop configuration

摘要

A source of polarisation-entangled photons that uses the spontaneous parametric downconversion process in the telecommunication wavelength band is reported. A 1 mm-long periodically poled lithium niobate waveguide was placed in a fibre loop to realise spontaneous parametric downconversion, and it was operated at room temperature. Two-photon interferences having visibilities greater than 84% before subtraction of accidental coincidence counts were observed.