Full characterization of the transmission properties of a multi-plane light converter

TL;DR

This paper thoroughly characterizes the transmission properties of multi-plane light converters, revealing their behavior both within and outside the design modes, and models their efficiency using random matrix theory.

Contribution

It introduces a numerical method to reconstruct the transmission matrix and develops an analytical model describing MPLC behavior as a random scattering medium.

Findings

Reconstructed transmission matrices inside and outside design modes.

Identified new metrics for evaluating MPLC efficiency.

Modeled MPLC as a random scattering medium in large mode regimes.

Abstract

Multi-plane light conversion allows to perform arbitrary transformations on a finite set of spatial modes with no theoretical restriction to the quality of the transformation. Even though the number of shaped modes is in general small, the number of modes transmitted by a multi-plane light converter (MPLC) is extremely large. In this work, we aim to characterize the transmission properties of a multi-plane light converter inside and, for the first time, outside the design-modes subspace. By numerically reconstructing the transmission matrix of such systems, we individuate new ways to evaluate their efficiency in performing the design transformation. Moreover, we develop an analytical random matrix model that suggests that in the regime of a large number of shaped modes an MPLC behaves like a random scattering medium with limited number of controlled channels.