High-dimensional entanglement for long distance quantum communication

In this paper, we provide a scheme to generate a high-dimensional entanglement source for long distance quantum communication. We utilize a continuous wave pump laser to produce polarization-time two-body four-dimensional entangled photon pairs. Under 20 mW of pump power, we achieve 700 entangled photon pairs per second with a fidelity of 89%±3%. Compared with other known high dimension entangled sources, the developed source in the paper is easy to transmit over a long distance and its phase stability is easy to achieve. Therefore, the source is more suited for the future long distance high-dimensional quantum communication tasks and testing the quantum nonlocality, for example, long distance high dimensional quantum key distribution, experimental testing two-particle Greenberger-Horne-Zeilinger theorem, implementation of two-particle quantum pseudo telepathy, etc.