Stitch-Free, Diamond-Scribed Silicon Nitride Photonic Integrated Circuits for the Visible Band
Abstract
Silicon nitride photonic integrated circuits for the visible band are conventionally built with a buried oxide overcladding and singulated with wafer-scale tooling, constraints that preclude evanescent access to the guided mode for externally integrated emitters. We report a PECVD grown Si3N4 platform designed around an air-clad waveguide whose evanescent field remains accessible along the full device length. Two process elements make this geometry practical at chip scale. Fixed-beam moving-stage electron-beam lithography writes 500 nm single-mode waveguides as one continuous exposure across the 5 mm chip, removing write-field stitching which, given the σ2/d4 scaling of sidewall scattering in this high-confinement geometry at 635 nm, would otherwise dominate the loss budget. Chip singulation is performed by pen-type diamond scribing along lithographically patterned markers registered to in-plane direction, cleaving the Si(100) substrate to yield end-facets within 2∘ of normal at 80 % yield. Structural characterization by scanning electron microscopy confirms stitch-free waveguide geometry and undamaged, near-vertical scribed facets; light is coupled end-fire into fabricated devices and guided to a microring with evanescent bus-to-ring coupling confirmed by scattering imaging, and a sidewall-roughness-dependent scattering-loss model indicates that loss remains low in the roughness regime consistent with the observed facet and sidewall quality. Building on the intrinsic emitter-resonator coupling demonstrated in, this platform extends monolithic Si3N4 photonics toward scalable visible-to-near-infrared quantum and classical circuits.
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BibTeX
@misc{mandal2026stitchfree,
title = {{Stitch-Free, Diamond-Scribed Silicon Nitride Photonic Integrated Circuits for the Visible Band}},
author = {Kishor Kumar Mandal and Lekshmi Eswaramoorthy and Parul Sharma and Anuj Kumar Singh and Brijesh Kumar and Tanmay Gupta and Venu Gopal Achanta and Anshuman Kumar},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.17480},
eprint = {2609.17480},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.17480},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Stitch-Free, Diamond-Scribed Silicon Nitride Photonic Integrated Circuits for the Visible Band
AU - Kishor Kumar Mandal
AU - Lekshmi Eswaramoorthy
AU - Parul Sharma
AU - Anuj Kumar Singh
AU - Brijesh Kumar
AU - Tanmay Gupta
AU - Venu Gopal Achanta
AU - Anshuman Kumar
PY - 2026
DA - 2026/09/15
PB - arXiv
DO - 10.48550/arxiv.2609.17480
UR - https://arxiv.org/abs/2609.17480
AB - Silicon nitride photonic integrated circuits for the visible band are conventionally built with a buried oxide overcladding and singulated with wafer-scale tooling, constraints that preclude evanescent access to the guided mode for externally integrated emitters. We report a PECVD grown Si_3N_4 platform designed around an air-clad waveguide whose evanescent field remains accessible along the full device length. Two process elements make this geometry practical at chip scale. Fixed-beam moving-stage electron-beam lithography writes 500 nm single-mode waveguides as one continuous exposure across the 5 mm chip, removing write-field stitching which, given the σ^2/d^4 scaling of sidewall scattering in this high-confinement geometry at 635 nm, would otherwise dominate the loss budget. Chip singulation is performed by pen-type diamond scribing along lithographically patterned markers registered to in-plane direction, cleaving the Si(100) substrate to yield end-facets within 2^∘ of normal at 80 % yield. Structural characterization by scanning electron microscopy confirms stitch-free waveguide geometry and undamaged, near-vertical scribed facets; light is coupled end-fire into fabricated devices and guided to a microring with evanescent bus-to-ring coupling confirmed by scattering imaging, and a sidewall-roughness-dependent scattering-loss model indicates that loss remains low in the roughness regime consistent with the observed facet and sidewall quality. Building on the intrinsic emitter-resonator coupling demonstrated in, this platform extends monolithic Si_3N_4 photonics toward scalable visible-to-near-infrared quantum and classical circuits.
ER -