Highly efficient polarization-entangled photon source using periodically poled lithium niobate waveguides

Abstract: In our experiment, two channels of a 3cm long periodically poled lithium niobate (PPLN) waveguide are used to generate the nondegenerate spontaneous parametric down conversion (NSPDC) photon pairs. We experimentally obtained the highly efficient polarization-entangled photon pairs by coherently combining two NSPDC processes, and keeping the phase stable over 30min. We can also prepare two entangled photon pairs with different central wavelengths with the help of wavelength division multiplex. [Copyright &y& Elsevier]