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The waveguide geometry has been precisely optimized to achieve a high evanescent field ratio (EFR) and minimize waveguide propagation losses. These optimizations significantly enhance the sensitivity of the waveguide, making it highly effective for evanescent field absorption-based gas sensing. Our optimized waveguide geometry demonstrates a notable EFR of 0.86, with a low propagation loss of just 1.07 dB\/cm, and achieves a sensitivity as high as ~1.12 \u00d7 10\u22124 ppm\u22121 for SSMW lengths as short as 0.9 cm.<\/jats:p>","DOI":"10.3390\/mi15121434","type":"journal-article","created":{"date-parts":[[2024,11,28]],"date-time":"2024-11-28T05:19:39Z","timestamp":1732771179000},"page":"1434","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Suspended Slot Membrane Waveguide Based on Germanium-on-Silicon-on-Insulator at \u03bb = 4.23 \u00b5m for CO2 Monitoring"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0829-4886","authenticated-orcid":false,"given":"Muhammad A.","family":"Butt","sequence":"first","affiliation":[{"name":"Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2529-8814","authenticated-orcid":false,"given":"Ryszard","family":"Piramidowicz","sequence":"additional","affiliation":[{"name":"Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,11,28]]},"reference":[{"key":"ref_1","first-page":"512","article-title":"A Review of Environmental Protection and Sustainable Development in Madagascar","volume":"5","author":"Harivelo","year":"2022","journal-title":"J"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Wu, L., Qing, C., and Jin, S. 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