中文摘要：

通过优化参量下转换产生EPR（Einstein-Podolsky-Rosen）纠缠态的方案,采用符合计数和后选择方法,制备了高保真度的EPR偏振纠缠态。结果表明,EPR纠缠态的保真度达到近0.99,EPR纠缠对的量度达到3 500Hz,克服了纠缠态的保真度和量度不能同时提高的局限,为多光子纠缠态的制备和双光子量子通信提供了非常稳定的纠缠源。

英文摘要：

By optimizing the scheme of EinsteinPodolsky-Rsoen（EPR） by spontaneous parametric down-conversion and using the technique of coincidence counting and post selection,the high fidelity polarization EPR entangled state has been prepared.The results show that the fidelity of EPR entangled state approach as almost 0.99,and the coincidence rate can be more than 3 500 Hz.It overcomes the limit that the fidelity and intensity of entanged state can′t increase synchronously.A stationary entangle source is supplied for preparation of the multi-photon entangled state and two-photon quantum communication.