Arahira Shin, Murai Hitoshi
Corporate Research & Development Center, Oki Electric Industry Co., Ltd., 1-16-8 Chuou, Warabi-shi, Saitama 335-8510, Japan.
Opt Express. 2012 Jul 2;20(14):15336-46. doi: 10.1364/OE.20.015336.
In this paper we report experimental investigation in transmission performance over standard single-mode optical fibers (SMFs) of polarization-entangled photon-pairs in a 1.5-μm band generated by cascaded second-harmonic generation and spontaneous parametric down conversion (c-SHG/SPDC) from a periodically poled LiNbO(3) (PPLN) ridge-waveguide device. Clear two-photon interference fringes were observed even after the transmission over 140 km of the SMF spools, remaining small degradation in the visibilities of less than 3%. The performance was also investigated by using optical attenuators, instead of the SMF spools, to study the maximum reach of the distribution of the entanglement in terms of loss penalty. The results show that the quantum entanglement could be distributed even with 50 dB of the transmission loss with violation of Bell inequality by using the c-SHG/SPDC-based photon-pair source.
在本文中，我们报告了对由周期性极化铌酸锂（PPLN）脊形波导器件通过级联二次谐波产生和自发参量下转换（c-SHG/SPDC）产生的1.5μm波段极化纠缠光子对在标准单模光纤（SMF）上的传输性能进行的实验研究。即使在SMF线轴上传输140公里后，仍观察到清晰的双光子干涉条纹，可见度的下降仍很小，小于3%。还使用光衰减器代替SMF线轴来研究纠缠分布在损耗代价方面的最大传输距离，从而对性能进行了研究。结果表明，通过使用基于c-SHG/SPDC的光子对源，即使在传输损耗为50dB的情况下，量子纠缠也能够进行分布，并且违反了贝尔不等式。
