Characterization and Exploitation of the Rotational Memory Effect in Multimode Fibers

TL;DR

This paper investigates the rotational memory effect in multimode fibers, providing a framework to characterize and exploit it despite real-world imperfections, with implications for imaging and telecommunications.

Contribution

It introduces an experimental and theoretical framework for studying and manipulating the rotational memory effect in multimode fibers, overcoming measurement challenges.

Findings

The RME can be precisely quantified using advanced processing techniques.

The shape of the angular correlation relates to core deformation geometry.

The framework aligns experimental data with theoretical predictions.

Abstract

In an ideal perfectly straight multimode fiber with a circular-core, the symmetry ensures that rotating the input wavefront leads to a corresponding rotation of the output wavefront. This invariant property, known as the rotational memory effect (RME), remains independent of the typically unknown output profile. The RME thus offers significant potential for imaging and telecommunication applications. However, in real-life fibers, this effect is degraded by intrinsic imperfections and external perturbations, and is challenging to observe because of its acute sensitivity to misalignments and aberrations in the optical setup. Thanks to processing involving a spatial light modulator, we efficiently overcome these measurement biases, allowing for precise quantification of the RME. We establish an experimental and theoretical framework for studying and manipulating the RME in multimode fibers. Theoretical predictions are consistent with experimental data and simulations, connecting the shape of the angular-dependent correlation of the RME to the geometrical properties of the core deformation. This work opens the road for accurate characterization of the distributed disorder originating from the fabrication process and calibration-less imaging in multimode fibers.