Abstract

Abstract

Abstract
Optical fiber sensors based on the phenomenon of plasmonic resonance can be interrogated applying different methods, the most common one being the spectral approach where the measurand information is derived from the reading of the wavelength resonance dip. In principle, a far better performance can be achieved considering the reading of the phase of the light at a specific wavelength located within the spectral plasmonic resonance. This approach is investigated in this work for fiber optic SPR sensors with overlays which are combinations of metallic and dielectric thin films, permitting not only to tune the wavelength of the SPR resonance but also the sensitivity associated with the phase interrogation of the sensors.

Abstract
In this work, a hybrid Fabry-Perot interferometer based on a novel four-bridge microstructured fiber is presented and characterized. The characterization of this cavity is performed in the L-band using two different instruments: an optical spectrum analyzer and an optical backscatter reflectometer. The Fabry-Perot output signal presents linear variation with temperature changes (sensitivity 9.8-11.9 pm/°C), variation with the polarization states of light and high stability. © 2014 SPIE.

Abstract
In this work a strain sensor based on a suspended core fiber is proposed. The sensor comprises a suspended core PCF between SMFs and is based on the multimode interference generated in these transitions. A strain sensitivity study for different sensing heads and stage separation lengths was carried out showing a sensitivity of -2.42 pm/mu epsilon for the best case. Also the sensing head was tested for curvature and temperature, showing in the first case that it is insensitive to curvature effects, and secondly, that for small sensor lengths it was insensitive to temperature variations.

Abstract
A multimodal interferometer based on a new microstructured fiber tip is proposed for detection of the evaporation process of acetone. The new geometry consists of a capillary tube in which an offset Ge-doped core is fused and spliced at the end of a single-mode fiber. The fiber tip sensor structure was immersed in liquid acetone and the evaporation process of acetone was monitored in real time. Due to the refractive index variation of the external medium with increasing temperature, a short detection time of similar to 1 s was achieved. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)