Suspended Slot Membrane Waveguide Based on Germanium-on-Silicon-on-Insulator at λ = 4.23 µm for CO<sub>2</sub> Monitoring

In this work, we propose a novel suspended slot membrane waveguide (SSMW) utilizing a germanium-on-silicon-on-insulator (Ge-on-SOI) platform for carbon dioxide (CO<sub>2</sub>) gas-sensing applications. The design and analysis focus on the absorption line of CO<sub>2</sub> in...

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Bibliographic Details
Main Authors: Muhammad A. Butt, Ryszard Piramidowicz
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Micromachines
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Online Access:https://www.mdpi.com/2072-666X/15/12/1434
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Summary:In this work, we propose a novel suspended slot membrane waveguide (SSMW) utilizing a germanium-on-silicon-on-insulator (Ge-on-SOI) platform for carbon dioxide (CO<sub>2</sub>) gas-sensing applications. The design and analysis focus on the absorption line of CO<sub>2</sub> in the mid-infrared region, specifically at a wavelength of 4.23 µm. 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 × 10<sup>−4</sup> ppm<sup>−1</sup> for SSMW lengths as short as 0.9 cm.
ISSN:2072-666X