Direct Generation of Tailored Pulse-Mode Entanglement
Francesco Graffitti, Peter Barrow, Alexander Pickston, Agata M. Brańczyk, Alessandro Fedrizzi
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 down-conversion processes. We achieve unprecedented quality in state generation-high rates, heralding efficiency, and state fidelity-as characterized via highly resolved time-of-flight fiber spectroscopy and two-photon interference. We employ this technique in a four-photon entanglement swapping scheme as a primitive for TFM-encoded quantum protocols.