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

Volume

18

Issue

5

fYear

2000

fDate

5/1/2000 12:00:00 AM

Firstpage

677

Lastpage

682

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;

fLanguage

English

Journal_Title

Lightwave Technology, Journal of

Publisher

ieee

ISSN

0733-8724

Type

jour

DOI

10.1109/50.842082

Filename

842082