Integrated entangled photons source from microcavity parametric down conversion

Mutually orthogonal polarization photons from Type-II parametric down conversion process in a circular microcavity were discussed based on the nonlinear interaction among whispering gallery modes. Furthermore, an onchip polarization entangled photons source can be obtained with integrated pump laser in the same microcavity and polarization beam splitter. Such an entangled photons resource will be useful in many areas, such as microcavity-QED and onchip quantum information techniques.