Generation and manipulation of entangled photons in a domain-engineered lithium niobate waveguide

TL;DR

This paper presents a domain-engineered lithium niobate waveguide capable of generating and dynamically manipulating polarization-entangled photon pairs with adjustable properties, advancing integrated quantum photonic circuits.

Contribution

It introduces a novel integration of electro-optic tuning with entangled photon generation in PPLN, enabling reconfigurable and switchable entanglement states.

Findings

Adjustable bandwidths and high entanglement degrees achieved.

Instantaneous switching of photon pair polarization states.

Potential for reconfigurable entanglement through domain design.

Abstract

We propose to integrate the electro-optic tuning function into polarization-entangled photon pair generation process in a periodically poled lithium niobate (PPLN). Due to the versatility of PPLN, both the spontaneously parametric down conversion and electro-optic polarization rotation effects could be realized simultaneously. Orthogonally-polarized and parallel-polarized photon pairs thus are instantly switchable by tuning the applied field. The characteristics of the source are investigated showing adjustable bandwidths and high entanglement degrees. Moreover, other kinds of reconfigurable entanglement are also achievable based on suitable domain-design. We believe the domain engineering is a very promising solution for next generation function-integrated quantum circuits.