1.
Appl Opt
; 30(12): 1474-9, 1991 Apr 20.
Article
in English
| MEDLINE
| ID: mdl-20700308
ABSTRACT
We describe a fiber optic interferometric refractive index sensor to illustrate that, by using the evanescent field of an optical waveguide, a potentially very sensitive determination of changes in the refractive index on the waveguide surface can be obtained. These changes can, e.g., be the result of immunoreactions. We used a Mach-Zehnder interferometer configuration with a flow-through cuvette in one arm with a decladded multimode glass fiber of 0.6-mm diameter and 2-cm interaction length. The obtained resolution in measuring refractive index changes is 1 x 10-(3). We also developed the theory describing the sensitivity of this sensor using the modal and the geometrical ray description.