Fabricación de fibras ópticas de plástico microestructuradas para el desarrollo de sensores ópticos

170 p.En este trabajo de tesis se han desarrollado técnicas avanzadas para la fabricación de Fibras Ópticas de Plástico Microestructuradas (FOPM) de forma precisa y controlada. En un primer bloque se analizan las técnicas de taladrado profundo y de apilamiento de capilares, empleadas en la creación de preformas estructuradas de alta calidad, partiendo de cilindros monolíticos de polímeros de elevada calidad óptica. En el segundo bloque se detalla el proceso de estirado de las preformas a FOPM, donde es necesario un control absoluto de la unidad de calentamiento y estirado. Por último, en el tercer bloque se muestran algunas de las FOPM diseñadas y fabricadas validando su empleo en diversas aplicaciones que van desde sensores de curvatura, rotación o presión hasta biosensores de glucosa. Además, se ha incluido un apéndice que ofrece información adicional relativa a la torre de fabricación

Fabrication Quality Assessment Based on the Coupling of a Dual-Core Microstructured Polymer Optical Fiber

In this paper we report on the theoretical analysis and fabrication of a dual-core microstructured polymer optical fiber (mPOF) and demonstrate how the coupling characteristics of a dual-core mPOF may be a key factor to assess the quality of the fabrication process. The coupling characteristics of this fiber have been tested and, for comparison purposes, simulations regarding the effects of inaccuracies during the manufacturing process were carried out to evaluate the fabrication quality. Results indicate that theoretical, simulation and experimental data are in good agreement, which highlights the uniformity of the microstructure along the fiber and the quality of its fabrication process. In fact, the manufactured mPOF reached a coupling efficiency up to 95.26%, which makes this mPOF appealing for applications in which highly efficient power couplers are required.This work was supported in part by the European Regional Development Fund, in part by the Ministerio de Economía y Competitividad under project RTI2018-094669-B-C31 and RTC2019-007194-4, and in part by the Gobierno Vasco/Eusko Jaurlaritza under projects IT933-16 and ELKARTEK (KK-2021/00092, KK-2021/00082)

Fabrication of Active Polymer Optical Fibers by Solution Doping and Their Characterization

This paper employs the solution-doping technique for the fabrication of active polymer optical fibers (POFs), in which the dopant molecules are directly incorporated into the core of non-doped uncladded fibers. Firstly, we characterize the insertion of a solution of rhodamine B and methanol into the core of the fiber samples at different temperatures, and we show that better optical characteristics, especially in the attenuation coefficient, are achieved at lower temperatures. Moreover, we also analyze the dependence of the emission features of doped fibers on both the propagation distance and the excitation time. Some of these features and the corresponding ones reported in the literature for typical active POFs doped with the same dopant are quantitatively similar among them. This applies to the spectral location of the absorption and the emission bands, the spectral displacement with propagation distance, and the linear attenuation coefficient. The samples prepared in the way described in this work present higher photostability than typical samples reported in the literature, which are prepared in different ways.This research was funded by European Regional Development Fund (ERDF), by Ministerio de Economia y Competitividad (MINECO) (TEC2015-638263-C03-1-R) and by Eusko Jaurlaritza (ELKARTEK KK-2016/0030, ELKARTEK KK-2016/0059, ELKARTEK KK-2017/00033, ELKARTEK KK-2017/00089, IT933-16). The work of Mikel Azkune was supported in part by a research fellowship from the Universidad del Pais Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Vicerrectorado de Euskera y Formacion Continua, while working on a Ph.D. degree

Fabrication and characterization of active polymer optical fibers with a ring-doped structure

This paper employs the solution-doping technique for the fabrication of polymer optical fibers (POFs) doped with two perylene derivatives, Lumogen Yellow 083 and Lumogen Red 305, in different combinations. With the solution-doping technique is very easy to control the amount of dopant penetration into the core of non-doped uncladded fibers, allowing the fabrication of active POFs with a novel ring-doped structure. In addition to manufacturing the fibers, these have also been optically characterized. Specifically, the influence of the combination of dopants, pumping power and wavelength, as well as the light propagation distance, have been measured and analyzed. Furthermore, time-resolved emission characteristics have also been measured to determine the fluorescence lifetimes and to extract information about the energy transfer between the dopants. Finally, the aim of this work has been to investigate the performance of the aforementioned POFs for fluorescent lighting applications, with a special focus on tunable light sources, and also for sensing applications.These results are funded in part by the Ministerio de Ciencia e Innovación -under projects RTC2019-007194-4, PID2021-122505OB-C31 and TED2021-129959B-C21,- and in part by Gobierno Vasco/Eusko Jaurlaritza under projects IT1452-22 and ELKARTEK (KK‑2021/00082, KK‑2021/00092)

Hydrogel-Core Microstructured Polymer Optical Fibers for Selective Fiber Enhanced Raman Spectroscopy

A new approach of Fiber Enhanced Raman Spectroscopy (FERS) is described within this article based on the use of Hydrogel-Core microstructured Polymer Optical Fibers (HyC-mPOF). The incorporation of the hydrogel only on the core of the Hollow-Core microstructured Polymer Optical Fiber (HC-mPOF) enables to perform FERS measurements in a functionalized matrix, enabling high selectivity Raman measurements. The hydrogel formation was continuously monitored and quantified using a Principal Component Analysis verifying the coherence between the components and the Raman spectrum of the hydrogel. The performed measurements with high and low affinity target molecules prove the feasibility of the presented HyC-mPOF platform.This work was funded in part by the Fondo Europeo de Desarrollo Regional (FEDER), in part by the Ministerio de Ciencia, Innovación y Universidades under projects RTC2019-007194-4, RTI2018-094669-B-C31 and MAT2014-5742 R and in part by the Gobierno Vasco/Eusko Jaurlaritza IT933-16, ELKARTEK KK-2019/00101 (μ4Indust), and ELKARTEK KK-2019/00051 (SMARTRESNAK)

Design, Fabrication and Testing of a High-Sensitive Fibre Sensor for Tip Clearance Measurements

A highly sensitive fibre bundle-based reflective optical sensor has been designed and fabricated for Tip Clearance measurements in a turbine rig. The sensor offers high spatial and temporal resolution. The sensor probe consists of a single-mode transmitting fibre and two concentric rings of receiving multimode fibres that collect reflected light in a differential detection gain configuration, yielding a highly linear calibration curve for distance measurements. The clearance measurement range is approximately 2 mm around the central point fixed at 3.2 mm from the probe tip, and the sensitivity of the probe is 61.73 mm(-1). The fibre bundle has been designed to ensure that the distance security specifications required for the experimental program of the turbine are met. The optical sensor has operated under demanding conditions set by the blade and casing design. The experimental results obtained so far are promising and lead us to think that the optical sensor has great potential for online clearance measurements with high precision.This work was funded in part by the Fondo Europeo de Desarrollo Regional (FEDER), in part by the Ministerio de Economia y Competitividad under project TEC2015-638263-C03-1-R, and in part by the Gobierno Vasco/Eusko Jaurlaritza IT933-16 and ELKARTEK (KK-2016/0030, KK-2017/00033, KK-2017/00089 and KK-2016/0059). The work of Josu Amorebieta is supported in part by a PhD fellowship from the Universidad del Pais Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Vicerrectorado de Euskera y Formacion Continua

Effects of Fabrication Methods on the Performance of Luminescent Solar Concentrators Based on Doped Polymer Optical Fibers

In this work, we detail two types of fabrication processes of four polymer optical fibers doped with lumogen dyes. The fiber preforms have been manufactured with two different methods: extrusion and casting. We have compared the performance of the two types of fibers as luminescent solar concentrators by calculating their optical efficiencies and concentration factors. The obtained results show better performance for those fibers manufactured by the casting process. We have also studied the photostability of the two types of fibers doped with the dye lumogen red under solar light radiation. A high thermal stability of the doped fibers has been observed.This work was funded in part by the Fondo Europeo de Desarrollo Regional (FEDER), in part by the Ministerio de Ciencia, Innovación y Universidades under projects RTC2019-007194-4, RTI2018-094669-B-C31 and MAT2014-5742-R and in part by the GobiernoVasco/Eusko Jaurlaritza IT933-16, ELKARTEK KK-2019/00101 (μ4Indust), and ELKARTEK KK-2019/00051 (SMARTRESNAK)

U-Shaped and Surface Functionalized Polymer Optical Fiber Probe for Glucose Detection

In this work we show an optical fiber evanescent wave absorption probe for glucose detection in different physiological media. High selectivity is achieved by functionalizing the surface of an only-core poly(methyl methacrylate) (PMMA) polymer optical fiber with phenilboronic groups, and enhanced sensitivity by using a U-shaped geometry. Employing a supercontinuum light source and a high-resolution spectrometer, absorption measurements are performed in the broadband visible light spectrum. Experimental results suggest the feasibility of such a fiber probe as a low-cost and selective glucose detector.This work has been funded in part by the European Regional Development Fund; in part by the Ministerio de Economia y Competitividad under project TEC2015-638263-C03-1-R; and in part by the Gobierno Vasco/Eusko Jaurlaritza under projects IT933-16, IT718-13, and ELKARTEK (KK-2016/0030, KK-2017/00033, KK-2017/00089, KK-2016/0059). Authors are also grateful to the technical and human support provided by SGIKER (UPV/EHU, MICINN, GV/EJ, ERDF, and ESF). The work of Mikel Azkune was supported in part by a research fellowship from the Universidad del Pais Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Vicerrectorado de Euskera y Formacion Continua

Fabricación de fibras ópticas de plástico microestructuradas para el desarrollo de sensores ópticos

170 p.En este trabajo de tesis se han desarrollado técnicas avanzadas para la fabricación de Fibras Ópticas de Plástico Microestructuradas (FOPM) de forma precisa y controlada. En un primer bloque se analizan las técnicas de taladrado profundo y de apilamiento de capilares, empleadas en la creación de preformas estructuradas de alta calidad, partiendo de cilindros monolíticos de polímeros de elevada calidad óptica. En el segundo bloque se detalla el proceso de estirado de las preformas a FOPM, donde es necesario un control absoluto de la unidad de calentamiento y estirado. Por último, en el tercer bloque se muestran algunas de las FOPM diseñadas y fabricadas validando su empleo en diversas aplicaciones que van desde sensores de curvatura, rotación o presión hasta biosensores de glucosa. Además, se ha incluido un apéndice que ofrece información adicional relativa a la torre de fabricación

Determinant factors in the convergence of welfare effort in OECD countries: a decomposition of the Theil indices

This article uses Theil's index to confirm the convergence of welfare effort in 21 developed countries. Taking advantage of the properties of this index, this article decomposes the dispersion of effort into its immediate determinants and thus illustrates that it is possible for there to be convergence in welfare effort but not in the intensity with which national systems protect their citizens.