{
  "abstract": "Astrophotonics offers a pathway towards compact and stable spectrographs for future large telescopes. The size of these spectrographs does not scale with the diameter of the telescope aperture; thus, they offer a cost-effective way to achieve astronomy science requirements compared to traditional optical spectrographs. A major limitation of current on-chip astrophotonic spectrographs is the significant loss incurred at interfaces between distinct components, particularly at the input and output fiber interfaces, limiting overall throughput. In this work, we investigate inverse-designed architectures to optimize transitions between these components to improve throughput. Inverse design formulates device design as an optimization problem, enabling non-intuitive geometries that can achieve high performance. We focus on optimizing coupling between an arrayed waveguide grating (AWG) spectrograph and an input single-mode fiber. Our approach explores two classes of fabrication-constrained inverse design. The first is shape optimization, which optimizes the geometry of the boundary of a coupling taper. The second is topology optimization, which optimizes the material distribution in a design region to gradually transform the optical mode between components. Both methods are implemented using the Tidy3D package from Flexcompute. We use germanium-doped silica for the core of the photonic components and silica as the cladding, and we use an SMF-28 fiber as input. This work demonstrates a pathway to improve astrophotonic spectrographs through computational inverse-design methods. Leveraging higher throughput, we can improve signal-to-noise ratios offered by photonic devices and position ourselves to design high-performance, cost-effective instrumentation for the next generation of telescopes, both on the ground and in space.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.24699",
  "author_total": 2,
  "authors": [
    {
      "name": "Vikram Seenivasan"
    },
    {
      "name": "Pradip Gatkine"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1gdbrbazet9n7.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.24699",
  "fulltext_url": null,
  "id": "1gdbrbazet9n7",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.24699",
  "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",
      "astro-ph.IM"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.24699",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-17",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/1gdbrbazet9n7.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:30:52Z",
      "native_id": "2610.24699",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.24699"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.IM",
      "subfield": "instrumentation-methods"
    }
  ],
  "title": "Inverse-designed tapers to improve throughput of on-chip astrophotonic spectrographs",
  "title_text": "Inverse-designed tapers to improve throughput of on-chip astrophotonic spectrographs",
  "type": "preprint",
  "updated_at": "2026-10-30T12:33:41Z",
  "url": "https://research.draconitic.com/paper/1gdbrbazet9n7",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1117/12.3105568",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}