Actively switchable non-degenerate polarization entangled photon pair distribution in a dense wave-division multiplexing

Abstract

We have realized experimentally a non-degenerate polarization-entangled photon pair distribution in a commercial telecom dense wave-division multiplexing device (DWDM) with 8 channels. A promising point of this work is that the entangled photon pair is obtained via spontaneously parametric down conversion in a single type-II periodically poled KTiOPO4 crystal without usual post-selection. Another promising advantage is that we can actively control and switch the distribution of the photon pair between different channel pairs in DWDM at will. There is no crosstalk between the different channel pair because of a limited emission bandwidth of the source. High raw visibility of greater than 90% in Bell-type interference measurement in each channel pair and the CHSH inequality S parameter of 2.63+/-0.08 prove high entanglement of our source. Our work is helpful for building quantum communication networks.