# Coupling quasi-phase matching: entanglement buildup in $\chi^{(2)}$ nonlinear waveguide arrays

## TL;DR

This paper introduces a novel coupling quasi-phase matching technique in nonlinear waveguide arrays that enhances multimode quantum entanglement and EPR steering, advancing continuous variables quantum information processing.

## Contribution

It proposes a new coupling quasi-phase matching method for efficient multimode quantum light generation, demonstrating its potential with current technology.

## Key findings

- Achieves multimode quantum entanglement.
- Demonstrates Einstein-Podolsky-Rosen steering buildup.
- Shows feasibility with existing technology.

## Abstract

Wavevector quasi-phase matching was devised in the 1960s as a way to boost nonlinear interactions with efficient quantum noise squeezing as one outstanding outcome. In the era of quantum technologies, we propose a new coupling quasi-phase matching for efficient generation of multimode downconverted quantum light in nonlinear waveguide arrays. We highlight this technique achieving multimode quantum entanglement and Einstein-Podolsky-Rosen steering buildup. We discuss the feasibility of this method with current technology and demonstrate its competitiveness as a resource for continuous variables quantum information.