Design of high brightness entangled source based on periodically poled KTiOPO4 crystal

Entangled states are key resource for quantum information processing. In linear optics quantum computing,the most widely used entanglement resource is polarization entangled photon pairs generated via type-II spontaneous parametric down-conversion. However, the brightness is not. sufficient to perform quantum communication experiment between ground and satellite. In this paper we have developed a high-brightness entangled resource based on periodic polarization and quasi-phase marched periodically poled KTiOPO4 crystal. The number of generated entangled pairs is about 1.6 x 10(4) s(-1) mW(-1) and the visibility is 27:1. Our source is with about one order of magnitude brighter than previous sources based on P-barium borate crystal. This leads to an immediate possibility for applications in the field of quantum key distribution, quantum teleportation and quantum computation. Particularly it would form a solid basis for future global quantum network.