High intensity polarization entangled source with a 2D nonlinear photonic crystal

We give a proposal on how to use a piece of two-dimension (2D) nonlinear photonic crystal to generate a polarization entangled source. It provides not only a high stability, but also a high entangled quality and a high intensity. Moreover, our scheme involves only practical experimental conditions and setup, and easy to realize. Therefore, it may have a potential application in the quantum world.