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Two-step frequency conversion for connecting distant quantum memories by transmission through an optical fiber

MetadataDetails
Publication Date2018-04-26
JournalJapanese Journal of Applied Physics
AuthorsShuhei Tamura, Kohei Ikeda, Kotaro Okamura, Kazumichi Yoshii, Feng-Lei Hong
InstitutionsKanagawa University, Japan Science and Technology Agency
Citations12

Long-distance quantum communication requires entanglement between distant\nquantum memories. For this purpose, photon transmission is necessary to connect\nthe distant memories. Here, for the first time, we develop a two-step frequency\nconversion process (from a visible wavelength to a telecommunication wavelength\nand back) involving the use of independent two-frequency conversion media where\nthe target quantum memories are nitrogen-vacancy centers in diamonds (with an\nemission/absorption wavelength of 637.2 nm), and experimentally characterize\nthe performance of this process acting on light from an attenuated CW laser. A\ntotal conversion efficiency of approximately 7% is achieved. The noise\ngenerated in the frequency conversion processes is measured, and the\nsignal-to-noise ratio is estimated for a single photon signal emitted by a\nnitrogen-vacancy (NV) center. The developed frequency conversion system has\nfuture applications via transmission through a long optical fiber channel at a\ntelecommunication wavelength for a quantum repeater network.\n