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Proceedings Paper

Theoretical investigation of silicon nitride waveguides for optical gas sensors in agricultural applications (Conference Presentation)
Author(s): Natnicha Koompai; Pichet Limsuwan; Xavier Le Roux; Laurent Vivien; Delphine Marris-Morini; Papichaya Chaisakul

Paper Abstract

Application of photonics for smart farming could have a tremendous impact on the economy and the well-being of world population. Silicon Photonics should be a promising platform to apply the photonic technologies at reasonable cost in agricultural-based countries for their economic agriculture products. Among several group-IV materials, Silicon Nitride (SiN) is one of the most interesting Si-compatible materials suitable for on-chip spectroscopic sensing in the near- and mid-IR region as it has a relatively large transparent windows and a sufficiently-high refractive index of ~ 2. In this presentation, we will discuss the use of Si3N4 on SiO2 waveguides for a wideband spectroscopic sensing. The target design would include optical wavelength from 2.5 µm to 3.5 µm, in which several agriculturally-important gas molecules can be detected such as H2O (water vapor), CO2 (carbon dioxide), N2O (Nitrous oxide), NH3 (Ammonia), C2H4 (Ethylene), CH4 (Methane), and the spectral range is also within the transparent windows of Si3N4 on SiO2 waveguide. Significantly, we focus our effort on achieving a waveguide structure that can support single-mode optical propagation for a broad spectral range within 2.5-3.5 µm, and at the same time, can maintain a good sensing performance for multi-gas spectroscopic sensing despite the compromised evanescent field confinement values owing to the wideband design. We investigated the detection performance in term of compactness, polarization dependence, detection limit, and fabrication tolerance.

Paper Details

Date Published: 2 April 2020
Proc. SPIE 11364, Integrated Photonics Platforms: Fundamental Research, Manufacturing and Applications, 113641S (2 April 2020); doi: 10.1117/12.2555458
Show Author Affiliations
Natnicha Koompai, Kasetsart Univ. (Thailand)
Pichet Limsuwan, King Mongkut’s Univ. of Technology Thonburi (Thailand)
Xavier Le Roux, CNRS, Univ. Paris-Sud, Univ. Paris-Saclay (France)
Laurent Vivien, CNRS, Univ. Paris-Sud, Univ. Paris-Saclay (France)
Delphine Marris-Morini, CNRS, Univ. Paris-Sud, Univ. Paris-Saclay (France)
Papichaya Chaisakul, Kasetsart Univ. (Thailand)

Published in SPIE Proceedings Vol. 11364:
Integrated Photonics Platforms: Fundamental Research, Manufacturing and Applications
Roel G. Baets; Peter O'Brien; Laurent Vivien, Editor(s)

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