# Air-core fiber distribution of hybrid vector vortex-polarization entangled states

## TL;DR

This paper demonstrates the experimental distribution of hybrid polarization-vector vortex entangled photon pairs through air-core fiber supporting OAM modes, enabling high-fidelity quantum state transfer for advanced quantum communication.

## Contribution

It introduces the first experimental fiber distribution of hybrid polarization-OAM entangled states using air-core fiber supporting OAM modes.

## Key findings

- High fidelity entanglement distribution confirmed by quantum state tomography.
- Violation of Bell inequalities demonstrates nonlocal correlations.
- Supports complex quantum states transmission via vectorial light modes.

## Abstract

Entanglement distribution between distant parties is one of the most important and challenging tasks in quantum communication. Distribution of photonic entangled states using optical fiber links is a fundamental building block towards quantum networks. Among the different degrees of freedom, orbital angular momentum (OAM) is one of the most promising due to its natural capability to encode high dimensional quantum states. In this article, we experimentally demonstrate fiber distribution of hybrid polarization-vector vortex entangled photon pairs. To this end, we exploit a recently developed air-core fiber which supports OAM modes. High fidelity distribution of the entangled states is demonstrated by performing quantum state tomography in the polarization-OAM Hilbert space after fiber propagation, and by violations of Bell inequalities and multipartite entanglement tests. The present results open new scenarios for quantum applications where correlated complex states can be transmitted by exploiting the vectorial nature of light.