Near-ideal spontaneous photon sources in silicon quantum photonics

TL;DR

This paper presents on-chip silicon photon sources that produce highly pure, indistinguishable, and efficient photon pairs suitable for scalable quantum photonic computing, using a novel dual-mode pump scheme.

Contribution

The authors demonstrate a new silicon-based photon source with high spectral purity, indistinguishability, and heralding efficiency, advancing integrated quantum photonics.

Findings

Spectral purity of 0.9904 ± 0.0006

Indistinguishability of 0.987 ± 0.002

Heralding efficiency over 90%

Abstract

While integrated photonics is a robust platform for quantum information processing, architectures for photonic quantum computing place stringent demands on high quality information carriers. Sources of single photons that are highly indistinguishable and pure, that are either near-deterministic or heralded with high efficiency, and that are suitable for mass-manufacture, have been elusive. Here, we demonstrate on-chip photon sources that simultaneously meet each of these requirements. Our photon sources are fabricated in silicon using mature processes, and exploit a novel dual-mode pump-delayed excitation scheme to engineer the emission of spectrally pure photon pairs through intermodal spontaneous four-wave mixing in low-loss spiralled multi-mode waveguides. We simultaneously measure a spectral purity of $0.9904 \pm 0.0006$, a mutual indistinguishably of $0.987 \pm 0.002$, and $>90\%$ intrinsic heralding efficiency. We measure on-chip quantum interference with a visibility of $0.96 \pm 0.02$ between heralded photons from different sources. These results represent a decisive step for scaling quantum information processing in integrated photonics.