Vincent P. Ruddy

TL;DR: In this paper, the authors performed evanescent waveabsorption in an aqueous dye solution using multimode fused silica fiber which was unclad at the sensing region.

TL;DR: In this paper, an unclad fiber was dipcoated with a thin layer of porous cladding within which a pH-sensitive dye was entrapped, and the performance of the pH sensor was reported and the potential of the technique for distributed and integrated optic sensing was discussed.

TL;DR: Intermodal diffusion in a large-diameter plastic-clad silica step-index fiber is measured with a near-field projection of the modal pattern onto a CCD camera and the diffusion process is found to obey a 1/θ(2) dependence.

TL;DR: In this paper, the authors investigated the dependence of absorbance on sample concentration and sample length in evanescent wave spectroscopy, carried out by means of weakly guiding step index optical fiber sensors, and found that absorbance was found to depend on the product of the sample bulk attenuation coefficient (α), the length of the fiber in contact with the sample (L ), and the inverse of the normalized frequency (V ) of the sensing section of the waveguide.

TL;DR: Spectral distortions that arise in evanescent-wave absorption spectra obtained with multimode step-index optical fibers are analyzed both theoretically and experimentally and demonstrate that even when the extinction coefficient of the external medium is small, anomalous dispersion of that medium in the vicinity of an absorption band must be considered.