We report an experimental realization of entanglement concentration using two polarization-entangled photon pairs produced by pulsed parametric down-conversion. In the meantime, our setup also provides a proof-in-principle demonstration of a quantum repeater. The quality of our procedure is verified by observing a violation of Bell's inequality by more than 5 standard deviations. The high experimental accuracy achieved in the experiment implies that the requirement of tolerable error rate in multi-stage realization of quantum repeaters can be fulfilled, hence providing a practical toolbox for quantum communication over large distances.
@article{arxiv.quant-ph/0301118,
title = {Experimental Realization of Entanglement Concentration and A Quantum Repeater},
author = {Zhi Zhao and Tao Yang and Yu-Ao Chen and An-Ning Zhang and Jian-Wei Pan},
journal= {arXiv preprint arXiv:quant-ph/0301118},
year = {2016}
}