{
  "abstract": "Integrated Kerr frequency combs are powerful tools for microwave photonics, spectroscopy, and optical communications. While traditional architectures rely on the anomalous-dispersion regime, this typically requires thick, highly strained silicon nitride layers that complicate standard CMOS-foundry fabrication. Thinner layers circumvent these fabrication constraints but yield normal-dispersion microcombs that generally require specific trigger mechanisms, such as deterministic seeding, due to the absence of spontaneous modulational instability. Here, we demonstrate the generation of a 20 GHz microcomb in the normal-dispersion regime, driven by a synchronized dual-pump scheme via electro-optic sidebands modulation. The platform leverages an Archimedean spiral geometry on a foundry-compatible, 350 nm-thin SiN platform. By employing adiabatic curvature engineering, the resonator balances a compact footprint with an intrinsic quality factor exceeding $7 \\times 10^6$, while effectively eliminating avoided mode crossings with higher order modes. This strong-dispersion architecture yields a low-repetition-rate microcomb featuring high power-per-line and picosecond-scale temporal profile, which enables the direct optical sampling and characterization of the out-coupled switching wave waveforms. The measured dynamics across a range of pump desynchronizations demonstrate excellent agreement with simulations. Our work establishes a scalable, strategy for footprint-efficient normal-dispersion microcomb generation at microwave frequencies, with potential for scaling to other wavelength ranges.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.31475",
  "author_total": 3,
  "authors": [
    {
      "name": "Van Doan Le"
    },
    {
      "name": "Julien Fatome"
    },
    {
      "name": "Erwan Lucas"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/7pgah3kyndsft.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.31475",
  "fulltext_url": null,
  "id": "7pgah3kyndsft",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.31475",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "physics.optics"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2609.31475",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-25",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/7pgah3kyndsft.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:24:52Z",
      "native_id": "2609.31475",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.31475"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.optics",
      "subfield": "optics-photonics"
    }
  ],
  "title": "Direct Observation of Switching-Wave Dynamics in 20 GHz Normal Dispersion Spiral Microresonators",
  "title_text": "Direct Observation of Switching-Wave Dynamics in 20 GHz Normal Dispersion Spiral Microresonators",
  "type": "preprint",
  "updated_at": "2026-10-30T12:24:52Z",
  "url": "https://research.draconitic.com/paper/7pgah3kyndsft",
  "venue": "arXiv",
  "versions": []
}