Near-ideal spontaneous photon sources in silicon quantum photonics

S Paesani,S Signorini,A Laing,L Pavesi,A Maïnos,M Borghi

doi:10.1038/s41467-020-16187-8

S Paesani, S Signorini + Show 4 more

Open Access

https://doi.org/10.1038/s41467-020-16187-8

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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 dual-mode pump-delayed excitation scheme to engineer the emission of spectrally pure photon pairs through inter-modal spontaneous four-wave mixing in low-loss spiralled multi-mode waveguides. We simultaneously measure a spectral purity of 0.9904 ± 0.0006, a mutual indistinguishability of 0.987 ± 0.002, and >90% intrinsic heralding efficiency. We measure on-chip quantum interference with a visibility of 0.96 ± 0.02 between heralded photons from different sources.

Highlights

While integrated photonics is a robust platform for quantum information processing, architectures for photonic quantum computing place stringent demands on high quality information carriers
Silicon quantum photonics[7], which is compatible with complementary metal-oxidesemiconductor (CMOS) fabrication, provides a potential platform for very large-scale quantum information processing[8,9,10]
We demonstrate the engineering of a CMOS-compatible source of heralded single photons using silicon photonics, which simultaneously meets the requirements for scalable quantum photonics: high purity, high heralding efficiency, and high indistinguishabilty

Summary

Introduction

While integrated photonics is a robust platform for quantum information processing, architectures for photonic quantum computing place stringent demands on high quality information carriers. All-photonic quantum computing architectures rely on arrays of many photon sources to achieve combinatorial speed-ups in quantum sampling algorithms[11,12], or to approximate an ondemand source of single photons[13,14,15], and supply entangling circuitry for general purpose quantum computing[8,16] In the former case, the level of indistinguishability among photons upper bounds the computational complexity of sampling algorithms[17]; in the latter case, photon impurity and distinguishability lead to logical errors[16,18]. We demonstrate the engineering of a CMOS-compatible source of heralded single photons using silicon photonics, which simultaneously meets the requirements for scalable quantum photonics: high purity, high heralding efficiency, and high indistinguishabilty

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