Experimental entanglement generation using multiport beam splitters

TL;DR

This paper presents a versatile experimental scheme using a three-port beam splitter to generate various genuine tripartite entangled states, such as W, G, and GHZ, with high fidelity, simplifying the process of creating complex entanglement.

Contribution

It introduces a simple, adaptable setup for generating multiple types of tripartite entangled states without changing the experimental arrangement.

Findings

Achieved fidelities up to 87.3% with ideal states.

Successfully generated W, G, and GHZ states.

Demonstrated a versatile method for tripartite entanglement creation.

Abstract

Multi-photon entanglement plays a central role in optical quantum technologies. One way to entangle two photons is to prepare them in orthogonal internal states, for example, in two polarisations, and then send them through a balanced beam splitter. Post-selecting on the cases where there is one photon in each output port results in a maximally entangled state. This idea can be extended to schemes for the post-selected generation of larger entangled states. Typically, switching between different types of entangled states require different arrangements of beam splitters and so a new experimental setup. Here, we demonstrate a simple and versatile scheme to generate different types of genuine tripartite entangled states with only one experimental setup. We send three photons through a three-port splitter and vary their internal states before post-selecting on certain output distributions. This results in the generation of tripartite W, G and GHZ states. We obtain fidelities of up to $(87.3 \pm 1.1)\%$ with regard to the respective ideal states, confirming a successful generation of genuine tripartite entanglement.