High-fidelity operation of quantum photonic circuits

TL;DR

This paper demonstrates high-fidelity quantum photonic circuits using silica-on-silicon waveguides, achieving near-perfect interference and entangling gates, advancing scalable quantum information processing.

Contribution

It presents the fabrication and testing of quantum photonic circuits with near-unit fidelity, including a spectrally tuned photon source and entangling logic gates, crucial for scalable quantum technologies.

Findings

Achieved non-classical interference with near-unity fidelity

Demonstrated a two-photon entangling logic gate with high fidelity

Fabricated quantum circuits from silica-on-silicon waveguides

Abstract

We demonstrate photonic quantum circuits that operate at the stringent levels that will be required for future quantum information science and technology. These circuits are fabricated from silica-on-silicon waveguides forming directional couplers and interferometers. While our focus is on the operation of quantum circuits, to test this operation required construction of a spectrally tuned photon source to produce near-identical pairs of photons. We show non-classical interference with two photons and a two-photon entangling logic gate that operate with near-unit fidelity. These results are a significant step towards large-scale operation of photonic quantum circuits.