Transport of spatial quantum correlations through an optical waveguide

TL;DR

This paper demonstrates that spatial quantum correlations, specifically intensity-difference squeezing, can be preserved during transport through a multi-fibre optical waveguide, advancing quantum imaging capabilities.

Contribution

It shows for the first time that quantum intensity correlations can be maintained in a multi-fibre waveguide, enabling spatial quantum information transport.

Findings

Quantum intensity correlations are preserved in a fibre bundle.

Localised intensity-difference squeezing is maintained.

Supports potential for quantum imaging applications.

Abstract

The ubiquity of optical communications is due in large part to the advent of the optical fibre, which allows for flexible and efficient routing of light-encoded information. Used as serial channels, single fibres have also been shown to be effective to transport quantum information, for instance in commercial quantum key distribution systems. As fibre technology progresses to support the transmission of full images, e.g. in endoscopic devices, the question arises whether this technology is also suitable for the parallel transport of spatial quantum information, such as quantum images. Here we demonstrate the transport of quantum intensity correlations through a conduit made of the ordered packing of thousands of fibres, in a way which preserves localised intensity-difference squeezing. Maintaining the spatial character of quantum information opens the way to the use of guided-light technology in the emergent field of quantum imaging.