A realistic design of evanescent field optical sensors, constituted by three different kinds of planar waveguides covered by a sensing polymeric overlay, is performed. More precisely, the slab, the embedded strip and the ridge waveguides are considered. The sensor operation is simulated, in both the cases of lossy guided and leaky mode propagation, via a home made computer code. The optimal waveguide transverse section and length are identified, the advantages and drawbacks are shown. The ridge waveguide sensor exhibits appreciable characteristics: for a concentration C w = 200 ppm of toluene in water, the absorbance pertaining to a device L = 2.6 cm long and for the guided quasi-TE00 mode is A ≅ 5, while it is A ≅ 0.054 for a device long L ≅ 24.1 μm and the leaky quasi-TE10 mode. The simulation results suggest that a selective excitation of the suitable propagation mode can enhance the sensor performance.
|Titolo:||Design of optic sensor for hydrocarbon detection|
|Titolo del libro:||Optics for the quality of life : 19th Congress of the International Commission for Optics|
|Editore:||Society of Photo-optical Instrumentation Engineers|
|Data di pubblicazione:||2003|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1117/12.527488|
|Appare nelle tipologie:||2.1 Contributo in volume (Capitolo o Saggio)|