High-quality entangled photon source by symmetric beam displacement design

TL;DR

This paper presents a robust, high-visibility polarization-entangled photon source using symmetric beam displacement and commercial components, suitable for quantum communication and sensing with potential for further improvements.

Contribution

The work introduces a versatile, stable entangled photon source based on symmetric beam displacement and type-0 SPDC, achieving over 99% entanglement visibility.

Findings

Achieved over 99% entanglement visibility

Generated N00N and Bell states for various quantum applications

Demonstrated system stability and potential for enhancement

Abstract

Entangled photon sources (EPSs) are pivotal in advancing quantum communication, computing and sensing. The demand for deploying efficient, robust EPSs in the field, characterized by exceptional (phase) stability, has become increasingly apparent. This work introduces a polarization-entangled photon source, leveraging type-0 spontaneous parametric down-conversion, and constructed using commercial bulk optomechanical components. Our system is versatile, enabling the generation of N00N states for sensing applications or Bell states for quantum key distribution protocols. We attained a maximal Bell inequality violation, with the average entanglement visibility exceeding 99% . The potential for further performance enhancements is also explored.