Title :
Sensitivity enhancement in evanescent optical waveguide sensors
Author :
Veldhuis, G.J. ; Parriaux, O. ; Hoekstra, H.J.W.M. ; Lambeck, P.V.
Author_Institution :
MESA Res. Inst., Twente Univ., Enschede, Netherlands
fDate :
5/1/2000 12:00:00 AM
Abstract :
It is shown, that the sensitivity of the effective refractive index on the cladding index in evanescent optical waveguide sensors, can be larger than unity. This implies that the attenuation of a guided wave propagating in a waveguide immersed in an absorptive medium can be made larger than that of a free-space wave propagating through the same medium. The conditions and physical explanation for this puzzling behavior are identified and as a practical application, an absorption sensor, based on a suspended silicon slab waveguide, is proposed where the sensitivity is enhanced by a factor of 1.35.
Keywords :
chemical sensors; claddings; optical sensors; optical waveguides; sensitivity; absorption sensor; absorptive medium; cladding index; effective refractive index; evanescent optical waveguide sensors; free-space wave propagation; guided wave propagating; guided wave propagation; physical explanation; puzzling behavior; sensitivity; sensitivity enhancement; suspended silicon slab waveguide; waveguide immersion; Absorption; Optical attenuators; Optical propagation; Optical refraction; Optical sensors; Optical surface waves; Optical variables control; Optical waveguides; Refractive index; Silicon;
Journal_Title :
Lightwave Technology, Journal of
