{
  "abstract": "Scaling optical input/output for co-packaged optics is limited by the fiber-to-chip interface. Conventional edge coupling offers low loss and broad bandwidth but confines channels to a single row along the chip facet. On the other hand, surface couplers are either narrowband or difficult to fabricate with high yield and, importantly, compete with back-end metal routing. In this work, we introduce volumetric edge coupling, in which the chip edge is structured in three dimensions so that optical coupling can occur over a two-dimensional region rather than along a single line, providing a route toward interfacing multiple waveguides with multiple cores of a multicore fiber while preserving optical access from the chip perimeter. We investigate a single-channel realization based on total-internal-reflection (TIR)-mediated evanescent coupling through the 54.7$^\\circ$ sidewall of a KOH-etched silicon cavity, with the coupling profile shaped by a wedged buried-oxide ridge. Finite-difference time-domain simulations predict a peak coupling efficiency of 88% (-0.56 dB) at 1550 nm and a 1-dB bandwidth of 86.45 nm spanning the C-band. The design further exhibits a vertical alignment tolerance of approximately $\\pm$2 $μ$m, weak sensitivity to transverse offsets up to 5 $μ$m, and a $\\pm$0.8$^\\circ$ 1-dB angular tolerance. The reflected optical field also provides a potential alignment signal, offering a path toward reduced active alignment overhead in future multicore implementations.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.20686",
  "author_total": 4,
  "authors": [
    {
      "name": "Hamdy Elshehaby"
    },
    {
      "name": "Omar Bakheet"
    },
    {
      "name": "Mohamed A. Swillam"
    },
    {
      "name": "Mohamed Elkabbash"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/edjz725qs68pr.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.20686",
  "fulltext_url": null,
  "id": "edjz725qs68pr",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.20686",
  "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.app-ph"
    ],
    [
      "arxiv",
      "physics.optics"
    ],
    [
      "openalex",
      "2208|Photonic and Optical Devices"
    ]
  ],
  "openalex": "W7213578925",
  "pdf_url": "https://arxiv.org/pdf/2609.20686",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-17",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/edjz725qs68pr.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:22:19Z",
      "native_id": "2609.20686",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.20686"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.app-ph",
      "subfield": "applied-instrumentation"
    },
    {
      "field": "physics",
      "origin": "arxiv:physics.optics",
      "subfield": "optics-photonics"
    }
  ],
  "title": "Volumetric Evanescent Edge Coupling for Fiber-to-Chip Optical I/O",
  "title_text": "Volumetric Evanescent Edge Coupling for Fiber-to-Chip Optical I/O",
  "type": "preprint",
  "updated_at": "2026-10-30T12:22:19Z",
  "url": "https://research.draconitic.com/paper/edjz725qs68pr",
  "venue": "arXiv",
  "versions": []
}