1.
Appl Opt
; 38(28): 6036-9, 1999 Oct 01.
Article
in English
| MEDLINE
| ID: mdl-18324126
ABSTRACT
The proportion of power carried in the superstrate medium by the guided modes of integrated optical waveguides can be increased by the addition of a thin high-index film. Enhanced refractive-index sensing is demonstrated with channel waveguide Mach-Zehnder interferometers with Ta(2)O(5) overlays. Sensitivity increases by a factor greater than 50, and a detection limit better than 5 x 10(-7) is obtained. This approach is broadly applicable to sensing at waveguide surfaces where the strength of evanescent fields dictates performance.