Optical Mode Control, Switching and Shaping In Few Mode Fiber Using a Fiber Piano

TL;DR

This paper demonstrates a fiber piano device capable of controlling, switching, and shaping spatial modes in few mode fibers, including at the single photon level, using different wavelengths and polarization techniques.

Contribution

It introduces the use of a fiber piano for precise spatial mode control in few mode fibers, extending capabilities to single photon levels and multiple wavelengths.

Findings

Fiber piano enables control of modes up to LP11 at 808 nm.

Mode control extends up to LP21 at 632.8 nm.

Single photon level mode control demonstrated with correlated photon pairs.

Abstract

This work investigates the use of a fiber piano in controlling spatial modes in few mode fibers. It has been found that together with sub-optimal coupling into SMF-28 fibre and half and quarter waveplates, the fiber piano is capable of producing and reproducing desired spatial modes up to $LP_{11}$ when using 808 nm light and up to $LP_{21}$ when using 632.8 nm light. The control of spatial mode profile extends down to the single photon level. This is demonstrated with the help of correlated photon pairs generated via spontaneous parametric down conversion.