{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T09:27:19Z","timestamp":1786958839720,"version":"build-2736575974"},"reference-count":57,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2026,8,15]],"date-time":"2026-08-15T00:00:00Z","timestamp":1786752000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100009620","name":"Youth Science and Technology Foundation of Gansu Province","doi-asserted-by":"publisher","award":["20JR10RA252"],"award-info":[{"award-number":["20JR10RA252"]}],"id":[{"id":"10.13039\/501100009620","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100009014","name":"Joint Innovation Fund Project of Lanzhou Jiaotong University and Corresponding Supporting University","doi-asserted-by":"publisher","award":["LH2025019"],"award-info":[{"award-number":["LH2025019"]}],"id":[{"id":"10.13039\/501100009014","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Foundation for Innovative Fundamental Research Group Project of Gansu Province","award":["25JRRA805"],"award-info":[{"award-number":["25JRRA805"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nanomaterials"],"abstract":"<jats:p>This paper systematically investigates the structural design and numerical characterization of ultra-compact low-loss waveguide bends on lithium niobate-on-insulator (LNOI) thin films via 3D-FDTD simulations. Six 90\u00b0 bend architectures are analyzed to unravel transmission behaviors and intrinsic loss mechanisms, including three smooth bend optimizations: straight\u2013bend lateral offset, local width tapering, and Euler\u2013circular hybrid curvature modulation, alongside resonant-cavity and corner-mirror L-shaped bends. All structures achieve evident loss reduction within proper parameter windows. At Reff = 5 \u03bcm, optimized smooth bends reach a minimum loss of 0.046 dB\/90\u00b0, outperforming standard circular bends, while the double-corner-mirror bend exhibits the lowest loss of 0.467 dB\/90\u00b0 among right-angle configurations. Pairwise parametric scans disclose competitive effects among diverse loss-mitigation pathways, demonstrating that simultaneous use of two optimization strategies fails to cut extra loss at equal device dimensions. Broadband and fabrication tolerance simulations verify flat spectral response across the telecom C band; smooth curved bends possess strong robustness against inclined sidewalls, and etch depth acts as the dominant factor governing device loss. This work delivers systematic parametric guidelines for the design and optimization of miniaturized LNOI routing waveguides for photonic interconnects.<\/jats:p>","DOI":"10.3390\/nano16161004","type":"journal-article","created":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T08:05:41Z","timestamp":1786953941000},"page":"1004","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Design of Ultra-Compact and High-Efficiency Waveguide Bends on Lithium Niobate Thin Films"],"prefix":"10.3390","volume":"16","author":[{"given":"Yi-Wen","family":"Wang","sequence":"first","affiliation":[{"name":"School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070, China"},{"name":"Gansu Center for Fundamental Research in Complex Systems Analysis and Control, Lanzhou Jiaotong University, Lanzhou 730070, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhi-Chen","family":"Wei","sequence":"additional","affiliation":[{"name":"School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070, China"},{"name":"Gansu Center for Fundamental Research in Complex Systems Analysis and Control, Lanzhou Jiaotong University, Lanzhou 730070, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiao-Dong","family":"Wen","sequence":"additional","affiliation":[{"name":"School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070, China"},{"name":"Gansu Center for Fundamental Research in Complex Systems Analysis and Control, Lanzhou Jiaotong University, Lanzhou 730070, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tian-Xue","family":"Ma","sequence":"additional","affiliation":[{"name":"Department of Mechanics, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing 100044, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3037","DOI":"10.1515\/nanoph-2024-0132","article-title":"Lithium niobate on insulator\u2014Fundamental opto-electronic properties","volume":"13","author":"You","year":"2024","journal-title":"Nanophotonics"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2078","DOI":"10.1021\/acsphotonics.2c01589","article-title":"Perspective on lithium-niobate-on-insulator photonics utilizing the electro-optic and acousto-optic effects","volume":"10","author":"Pan","year":"2023","journal-title":"ACS Photonics"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1415","DOI":"10.3762\/bjnano.15.114","article-title":"Lithium niobate on insulator: An emerging nanophotonic crystal for optimized light control","volume":"15","author":"Murali","year":"2024","journal-title":"Beilstein J. 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