Spectral multiplexing for scalable quantum photonics using an atomic frequency comb quantum memory and feed-forward control

TL;DR

This paper demonstrates a scalable quantum memory system that uses spectral multiplexing and feed-forward control to store and manipulate multiple photon states with high fidelity, advancing quantum communication technologies.

Contribution

It introduces a method combining atomic frequency comb memory with spectral multiplexing and feed-forward control for scalable quantum photonics.

Findings

Stored up to 26 spectral modes with 97% fidelity.

Implemented feed-forward-controlled frequency manipulation.

Showed potential for scalable quantum repeaters.

Abstract

Future multi-photon applications of quantum optics and quantum information science require quantum memories that simultaneously store many photon states, each encoded into a different optical mode, and enable one to select the mapping between any input and a specific retrieved mode during storage. Here we show, with the example of a quantum repeater, how to employ spectrally-multiplexed states and memories with fixed storage times that allow such mapping between spectral modes. Furthermore, using a Ti:Tm:LiNbO3 waveguide cooled to 3 Kelvin, a phase modulator, and a spectral filter, we demonstrate storage followed by the required feed-forward-controlled frequency manipulation with time-bin qubits encoded into up to 26 multiplexed spectral modes and 97% fidelity.