No abstract

An ultracompact, cost-effective, and highly accurate fiber optic temperature sensor is proposed and demonstrated. The sensing head consists of Fabry-Perot microcavity formed by an internal mirror made of a thin titanium dioxide (TiO) film and a microscopic segment of single-mode fiber covered with Poly(dimethylsiloxane) (PDMS). Due to the high thermo-optic coefficient of PDMS the reflectance of the fiber-PDMS interface varies strongly with temperature which in turn modifies the amplitude of the interference pattern. To quantify the changes of the latter we monitored the visibility of the interference pattern and analyzed it by means of the fast Fourier transform. Our sensor exhibits linear response, high sensitivity, and response time of 14 seconds. We believe that the microscopic dimensions along with the performance of the sensor here presented makes it appealing for sensing temperature in PDMS microfluidic circuits or in biological applications.

No abstract

No abstract

No abstract

No abstract

A simple and compact fiber optic sensor based on a two-core fiber is demonstrated for high-performance measurements of refractive indices (RI) of liquids. In order to demonstrate the suitability of the proposed sensor to perform high-sensitivity sensing in a variety of applications, the sensor has been used to measure the RI of binary liquid mixtures. Such measurements can accurately determine the salinity of salt water solutions, and detect the water content of adulterated alcoholic beverages. The largest sensitivity of the RI sensor that has been experimentally demonstrated is 3,119 nm per Refractive Index Units (RIU) for the RI range from 1.3160 to 1.3943. On the other hand, our results suggest that the sensitivity can be enhanced up to 3485.67 nm/RIU approximately for the same RI range.

, FR.; Milián Enrique, C.; Torres-Gómez, I.; Torres-Cisneros, M.; Ferrando Cogollos, A. (2014). Supercontinuum optimization for dual-soliton based light sources using genetic algorithms in a grid platform. Optics Express. 22(19) Abstract: We present a numerical strategy to design fiber based dual pulse light sources exhibiting two predefined spectral peaks in the anomalous group velocity dispersion regime. The frequency conversion is based on the soliton fission and soliton self-frequency shift occurring during supercontinuum generation. The optimization process is carried out by a genetic algorithm that provides the optimum input pulse parameters: wavelength, temporal width and peak power. This algorithm is implemented in a Grid platform in order to take advantage of distributed computing. These results are useful for optical coherence tomography applications where bell-shaped pulses located in the second near-infrared window are needed.