Efficient and pure femtosecond-pulse-length source of polarization-entangled photons

TL;DR

This paper introduces a highly efficient, pure, and polarization-entangled photon source using femtosecond pulses, optimized for quantum information applications with high fidelity, purity, and interference visibility.

Contribution

The paper presents a novel femtosecond-pulse-based source that simultaneously achieves high heralding efficiency, purity, and entanglement fidelity for telecom photon pairs.

Findings

Achieved near-perfect non-classical interference with 100% visibility

Produced frequency-uncorrelated telecom photon pairs

Demonstrated high quantum state purity and entanglement fidelity

Abstract

We present a source of polarization entangled photon pairs based on spontaneous parametric downconversion engineered for frequency uncorrelated telecom photon generation. Our source provides photon pairs that display, simultaneously, the key properties for high-performance quantum information and fundamental quantum science tasks. Specifically, the source provides for high heralding efficiency, high quantum state purity and high entangled state fidelity at the same time. Among different tests we apply to our source we observe almost perfect non-classical interference between photons from independent sources with a visibility of $(100\pm5)\%$.