title: Frequency downconversion for a quantum network.
abstract: By using a parametric downconversion process with a strong signal field injection, we demonstrate coherent frequency downconversion from a pump photon to an idler photon. Contrary to a common misunderstanding, we show that the process can be free of quantum noise. With an interference experiment, we demonstrate that the coherence is preserved in the conversion process. This may lead to a high-fidelity quantum state transfer from a high-frequency photon to a low-frequency photon and connects a missing link in a quantum network. With this scheme of coherent frequency downconversion of photons, we propose a method of single-photon WDM.
authors.affiliation: Department of Physics, Indiana University-Purdue University Indianapolis,402 N. Blackford Street, Indianapolis, Indiana 46202, USA.
authors.forename: Yu
authors.initials: Y
authors.lastname: Ding
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Ou