# Near-unity indistinguishability single photon source for large-scale integrated quantum optics

## TL;DR

This paper presents a highly coherent, indistinguishable single photon source integrated on a chip using quantum dots, achieving near-unity indistinguishability suitable for scalable quantum information processing.

## Contribution

The authors demonstrate a triggered resonance fluorescence single photon source with high purity and indistinguishability on integrated waveguides, advancing scalable quantum photonic technologies.

## Key findings

- Achieved 99.1% single-photon purity with multi-mode waveguides.
- Achieved 97.5% indistinguishability in multi-mode waveguides.
- Demonstrated scalability for on-chip quantum applications.

## Abstract

Integrated single photon sources are key building blocks for realizing scalable devices for quantum information processing. For such applications highly coherent and indistinguishable single photons on a chip are required. Here we report on a triggered resonance fluorescence single photon source based on In(Ga)As/GaAs quantum dots coupled to single- and multi-mode ridge waveguides. We demonstrate the generation of highly linearly polarized resonance fluorescence photons with 99.1% (96.0%) single-photon purity and 97.5% (95.0%) indistinguishability in case of multi-mode (single-mode) waveguide devices fulfilling the strict requirements imposed by multi-interferometric quantum optics applications. Our integrated triggered single photon source can be readily scaled up, promising a realistic pathway for on-chip linear optical quantum simulation, quantum computation and quantum networks.