Silicon on silicon dioxide slot waveguide evanescent field gas absorption sensor

Several trace gases such as H 2 O, CO, CO 2 , NO, N 2 O, NO 2 and CH 4 strongly absorb in the mid-IR spectral region due to their fundamental rotational and vibrational transitions. In this work, we propose an evanescent field absorption gas sensor based on silicon/silicon dioxide slot waveguide at...

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Bibliographic Details
Published in:Journal of modern optics 2018-01, Vol.65 (2), p.174-178
Main Authors: Butt, M. A., Khonina, S. N., Kazanskiy, N. L.
Format: Article
Language:English
Subjects:
Absorption
Carbon dioxide
evanescent field ratio
finite element method
Gas absorption
Gas sensors
Gases
Methane
methane gas
Mid-IR
Nitrogen dioxide
Nitrous oxide
Rotational spectra
Silicon
Silicon dioxide
Slot waveguide
Trace gases
Wave propagation
Waveguides
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Summary:Several trace gases such as H 2 O, CO, CO 2 , NO, N 2 O, NO 2 and CH 4 strongly absorb in the mid-IR spectral region due to their fundamental rotational and vibrational transitions. In this work, we propose an evanescent field absorption gas sensor based on silicon/silicon dioxide slot waveguide at 3.39 μm for sensing of methane gas. These waveguides can provide the highest evanescent field ratio (EFR) > 47% with adequate dimensions. Higher EFR values often come at an expense of higher propagation losses. These waveguides have relatively higher losses as compared to conventional waveguides, such as rib and slab waveguides, as these fundamental losses are static and the proposed sensing mechanism is established on the incremental loss due to the absorption of the gas. Therefore, incident power can always be incremented to compensate the waveguide losses.
ISSN:0950-0340
1362-3044
DOI:10.1080/09500340.2017.1382596