Direct generation of tailored pulse-mode entanglement

TL;DR

This paper introduces a novel method for directly generating high-quality entangled time-frequency mode states of light, advancing quantum information processing with spectral encoding.

Contribution

It presents a new single-pass, tailored downconversion technique for producing entangled TFM states with high rates, efficiency, and fidelity, suitable for quantum protocols.

Findings

High-rate entangled TFM state generation achieved

Enhanced heralding efficiency and state fidelity demonstrated

Successful implementation in a four-photon entanglement swapping scheme

Abstract

Photonic quantum technology increasingly uses frequency encoding to enable higher quantum information density and noise resilience. Pulsed time-frequency modes (TFM) represent a unique class of spectrally encoded quantum states of light that enable a complete framework for quantum information processing. Here, we demonstrate a technique for direct generation of entangled TFM-encoded states in single-pass, tailored downconversion processes. We achieve unprecedented quality in state generation---high rates, heralding efficiency and state fidelity---as characterised via highly resolved time-of-flight fibre spectroscopy and two-photon interference. We employ this technique in a four-photon entanglement swapping scheme as a primitive for TFM-encoded quantum protocols.