Actively switchable nondegenerate polarization-entangled photon-pair distribution in dense wave-division multiplexing
Zhi‐Yuan Zhou, Yun-Kun Jiang, Dong-Sheng Ding, Bao‐Sen Shi, Guang‐Can Guo · Physical Review A · 2013
We have demonstrated experimentally a nondegenerate polarization-entangled photon-pair distribution in a commercial telecom dense wave-division multiplexing device (DWDM) with eight channels. A promising point of this experiment is that an entangled photon pair is obtained via spontaneous parametric down conversion in a single type-II periodically poled KTiOPO${}_{4}$ crystal without postselection. Another promising advantage is that we can actively switch the distribution of the photon pair between different channel pairs in DWDM at will. There is no crosstalk between different channel pairs because of a limited emission bandwidth of the source. Maximum raw visibility of $97.88%\ifmmode\pm\else\textpm\fi{}0.86%$ obtained in a Bell-type interference experiment and a Clauser-Horne-Shimony-Holt (CHSH) inequality $S$ parameter of $2.63\ifmmode\pm\else\textpm\fi{}0.08$ calculated prove high entanglement of our source. Our work is helpful for building quantum communication networks.