{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,16]],"date-time":"2026-04-16T15:21:25Z","timestamp":1776352885649,"version":"3.51.2"},"reference-count":23,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2012,2,23]],"date-time":"2012-02-23T00:00:00Z","timestamp":1329955200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Slot waveguides are becoming more and more attractive optical components, especially for chemical and bio-chemical sensing. In this paper an accurate analysis of slot waveguide fabrication tolerances is carried out, in order to find optimum design criteria for either homogeneous or absorption sensing mechanisms, in cases of low and high aspect ratio slot waveguides. In particular, we have focused on Silicon On Insulator (SOI) technology, representing the most popular technology for this kind of devices, simultaneously achieving high integration capabilities, small dimensions and low cost. An accurate analysis of single mode behavior for high aspect ratio slot waveguide has been also performed, in order to provide geometric limits for waveguide design purposes. Finally, the problem of coupling into a slot waveguide is addressed and a very compact and efficient slot coupler is proposed, whose geometry has been optimized to give a strip-slot-strip coupling efficiency close to 100%.<\/jats:p>","DOI":"10.3390\/s120302436","type":"journal-article","created":{"date-parts":[[2012,2,23]],"date-time":"2012-02-23T11:22:02Z","timestamp":1329996122000},"page":"2436-2455","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":50,"title":["Optimizing SOI Slot Waveguide Fabrication Tolerances and Strip-Slot Coupling for Very Efficient Optical Sensing"],"prefix":"10.3390","volume":"12","author":[{"given":"Vittorio M. N.","family":"Passaro","sequence":"first","affiliation":[{"name":"Photonics Research Group, Dipartimento di Elettrotecnica ed Elettronica, Politecnico di Bari, Via Edoardo Orabona 4, 70125 Bari, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mario","family":"La Notte","sequence":"additional","affiliation":[{"name":"Photonics Research Group, Dipartimento di Elettrotecnica ed Elettronica, Politecnico di Bari, Via Edoardo Orabona 4, 70125 Bari, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2012,2,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"197","DOI":"10.1109\/JPHOT.2009.2031596","article-title":"Label-free biosensing with a slot-waveguide-based ring resonator in silicon on insulator","volume":"1","author":"Claes","year":"2009","journal-title":"IEEE Photonics J"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1012","DOI":"10.3390\/s90201012","article-title":"Efficient chemical sensing by coupled slot SOI waveguides","volume":"9","author":"Passaro","year":"2009","journal-title":"Sensors"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"48","DOI":"10.1109\/JPHOT.2009.2025602","article-title":"Enhanced evanescent confinement in multiple-slot waveguides and its application in biochemical sensing","volume":"1","author":"Sun","year":"2009","journal-title":"IEEE Photonics J"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2979","DOI":"10.1109\/JLT.2011.2165203","article-title":"Slot and layer-slot waveguide in the visible spectrum","volume":"29","author":"Testa","year":"2011","journal-title":"J. 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