Versatile method for two-photon entanglement generation

US Patent Application Publication: US 18/895,730The present invention relates to a versatile source of entangled photon paris, generating photon paris in at least two nonlinear optical processes, such as spontaneuous parametric down conversion (SPDC) or spontaneous foru-wave mixing (SFWM), occurring at spatially separate locations in a single monolithic non-linear material, wherein a photon (photons) from a coherent pump light source is(are) converted into pairs of photon with diffferent wavelengths to the pump. Polarization entanglement is produce by the coherent combination of these photon pair emissions such that they are indistinguishable in all degrees of freedom except their polarization state, where this coherent combination is achieved through balanced beam displacing (BBD).