Frequency down-conversion for a quantum network

TL;DR

This paper demonstrates a noise-free, coherent frequency down-conversion process for photons using parametric down-conversion with strong signal injection, enabling high-fidelity quantum state transfer and potential quantum network applications.

Contribution

It introduces a novel method for noise-free, coherent frequency down-conversion of photons, addressing a key challenge in quantum communication.

Findings

Coherent frequency down-conversion can be achieved without quantum noise.

Coherence is preserved during the frequency conversion process.

The scheme enables high-fidelity quantum state transfer and wavelength division multiplexing.

Abstract

By using parametric down-conversion process with a strong signal field injection, we demonstrate coherent frequency down-conversion 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 high frequency photon to low frequency photon and connects a missing link in a quantum network. With this scheme of coherent frequency down-conversion of photons, we propose a method of single-photon wavelength division multiplexing.