Processing entangled photons in high dimensions with a programmable light converter

TL;DR

This paper introduces a reconfigurable, high-dimensional entangled photon processor based on multi-plane light conversion, enabling advanced manipulation and certification of entanglement for quantum information applications.

Contribution

It presents a novel MPLC-based platform for processing high-dimensional entangled photons, overcoming limitations of traditional integrated interferometers.

Findings

Certified three-dimensional entanglement in two bases

Performed 400 arbitrary transformations on entangled photons

Converted mode basis for entanglement distribution

Abstract

High-dimensional entanglement offers a variety of advantages for both fundamental and applied applications in quantum information science. A central building block for such applications is a programmable processor of entangled states, which is crucial for the certification, manipulation and distribution of high-dimensional entanglement. The leading technology for processing photons is integrated multiport interferometers. However, such devices are incompatible with structured light, and their scaling is challenging. Here, we unlock these limitations by demonstrating a reconfigurable processor of entangled photons in high-dimensions that is based on multi-plane light conversion (MPLC), a technology that was recently developed for multiplexing hundreds of spatial modes for classical communication. We use our programmable MPLC platform to certify three-dimensional entanglement in two mutually unbiased bases, perform 400 arbitrary random transformations on entangled photons, and convert the mode basis of entangled photons for entanglement distribution.