Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7223543 | Optik - International Journal for Light and Electron Optics | 2018 | 6 Pages |
Abstract
The mid-IR spectrum contains absorption peaks for a wide variety of trace gases, for instance, N2O, CO, CO2, H2O, NO2, NH3, NO and CH4 etc. These gases strongly absorb in the mid-IR >2.5â¯Î¼m spectral region due to their fundamental rotational and vibrational transitions. In this work, we propose a silicon-on-sapphire (SOS) rib waveguide design at 4.67â¯Î¼m for carbon monoxide (CO) gas sensing based on the evanescent field absorption. The exponentially decaying evanescent fields in the lower index region of a waveguide offer a high perspective in the realization of a variety of sensors. Numerous waveguide dimensions are modelled and studied in order to achieve an optimal evanescent field ratio (EFR) with lowest possible total losses of the waveguides. The total losses of these waveguides are in the range of 2.59-3.89â¯dB and 1.51-1.76â¯dB for TE and TM modes, respectively.
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Engineering
Engineering (General)
Authors
M.A. Butt, S.N. Khonina, N.L. Kazanskiy,