Comunicaciones y ponencias de congresos - Biltzarrak eta Argitalpenak
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Publication Open Access Risks of the digital euro project(Dykinson, 2025) Martín-Lanas, Javier; Derecho; ZuzenbideaIn this text, we will examine some of the main risks associated with the future Digital Euro (DE, hereafter). To unpack these threats posed by the new currency, we will employ a structure divided into two main sections. In the first section, we will present a synthesis of the nature, features, and properties of money as a fundamental institution for the proper functioning of society. We will not refer to the DE here or to any other specific form of money; the aim is rather to clearly outline the qualities that a good [asset] ‘must’ possess for a society to adopt it as money. The origin, evolution, and characteristics of money are topics widely debated in monetary theory, so we will provide as comprehensive a synthesis as possible without delving into technical subtleties. We anticipate that our stance in this debate aligns with an evolutionary theory of money, wherein money emerges spontaneously to fulfil individuals’ needs, acquiring diverse forms across history and geographies. This is currently the dominant view, though alternative theories – such as Modern Monetary Theory (MMT) – argue that money is, in essence and by nature, a state creation. This first section may seem somewhat lengthy to readers unfamiliar with monetary theory, but only by thoroughly grounding our analysis in these conceptual foundations will we be able to assess the full implications of the DE’s arrival and the potential risks its adoption may entail. In the second section, we will first outline the basic features of the new digital currency (based on currently available information) and then interweave them with the essential properties of sound money (examined individually in the preceding section). As we will emphasize later, given the embryonic stage of the DE project all conclusions drawn here should necessarily be treated as strictly provisional in nature. Let us conclude by sharing the origin of our interest in this subject. I previously worked for a banking institution (one of Spain’s largest commercial banks) providing services related to anti-money laundering. Fulfilling this role required interpreting data of all types stored in the institution’s databases, and in doing so, I came to understand the power derived from studying users’ habits. In this regard, the advent of the DE will enable authorities with sanctioning powers to gain more direct access to data on the economic behaviour of European Union citizens. And this could entail a reduction in citizens’ privacy – perhaps the most delicate aspect of the project. This is the catalyst that has led us to reflect on the issue.Publication Embargo Insights into the q Exponent in Power Measure with Choquet-based generalizations for classification problems(Springer, 2025-07-09) Lucca, Giancarlo; Asmus, Tiago da Cruz; Marco Detchart, Cedric; Santos, Helida; Camargo, Heloisa A.; Yamin, Adenauer; Reiser, Renata; Bustince Sola, Humberto; Pintanel, Alice ; Pereira Dimuro, Graçaliz; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika; Institute of Smart Cities - ISCChoquet-integrals are averaging aggregation functions based on a fuzzy measure that accounts for both the significance of each attribute being aggregated and the interactions between the variables. The effectiveness of a fuzzy measure can be characterized by its accuracy in modeling the relationship or association degree among the elements to be aggregated. In the literature, it is known that amid conventional fuzzy measures, the Power Measure (PM) presents statistically superior performance. This study explores the q exponent impact in the PM on the performance of different Choquet-based integrals when used in fuzzy rulebased classification systems. We aim to analyze how fixed q values influence classification accuracy across thirty-three benchmark datasets. The updated results reveal that smaller q values (e.g., q = 0.1 and q = 0.5) continue to yield superior accuracy, while larger values (q ≥ 100) tend to a performance stabilization. Among the tested methods, the generalization named CF1F2-integral achieves the highest classification accuracy, effectively adapting to different parameter settings.Publication Open Access Q/V-Band Gap-Waveguide-based circularly-polarized antenna(IEEE, 2025-05-21) Leoz-Beltrán, Iñigo; Iriarte Galarregui, Juan Carlos; Pérez Quintana, Dayan; Teberio Berdún, Fernando; Beruete Díaz, Miguel; Ederra Urzainqui, Íñigo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PRO-UPNA 11893This paper presents the design of an all-metal Gap Waveguide-based antenna. The design is intended for satellite communications as it covers the Q/V-Band, comprised between 37.5 and 42.5 GHz and between 47.5 and 52.4 GHz. This antenna operates with circular polarization, featuring an Axial Ratio below 1.5 dB at both frequency bands. The design includes a transition from an standard WR waveguide to a Ridge Gap Waveguide. The simulation of the whole system shows return losses higher than 10 dB at the bands of interest. Furthermore, this unit cell antenna achieves a maximum gain of 11.9 dB at 48.8 GHz.Publication Open Access A SiGe integrated active phased array antenna for a 183GHz water-vapor radiometer(IEEE, 2025-05-21) Herrera-Martín, Juan M.; Urain, Álvaro; Río, David del; González Posadas, Vicente; Ederra Urzainqui, Íñigo; Teniente Vallinas, Jorge; Berenguer, Roc; Segovia-Vargas, Daniel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISCMillimeter-wave radiometers can benefit from state-of-the-art on-chip technologies to construct a fully integrated front-end at frequencies above 100 GHz. The first step is to integrate a fully capable antenna design with a complex low-low noise amplifier in the same technology. This paper presents the integration simulation of a passive antenna array in IHP's SiGe 130 nm BiCMOS SG13G2 process and a 3-stage low-noise amplifier using the same technology. The final seamlessly integrated design proves to be a viable first building block for a future complete radiometer frontend-on-a-chip for frequencies exceeding 100 GHz.Publication Open Access Mapping indicators for morphological informality in Nairobi, Kenya using satellite imagery(IEEE, 2025-07-16) Hafner, Sebastian; Comerio de Paulo, Manuella; Zhao, Qunshan; Kuffer, Monika; Engstrom, Ryan; Thomson, Dana R.; Onyambu, Francis C.; Kabaria, Caroline; Elias, Peter; Abascal, Ángela; Tregonning, Grant; Odulana, Oluwatoyin; Shonowo, Adenike; Alugbin, Bunmi; Baruwa, Kehinde; Middleton, Alexandra; Albuquerque, João Porto de ; Ingeniería; IngeniaritzaOver one billion people globally live in slums, informal settlements, and other deprived areas. However, maps of deprived areas are often unavailable or over-simplistic, distinguishing only between slums and formal areas. Recent research advocates for a multidimensional approach to better account for the complexity of deprivation. Previous studies have mapped the unplanned urbanization domain of deprivation using morphometrics derived from building footprint data. This study explores leveraging Earth observation data for scalability and regular updates by using high-resolution satellite imagery and deep learning to map indicators for morphological informality in Nairobi, Kenya. The proposed model combines a ResNet backbone with three classification heads to map the two indicators: irregular settlement layout (ISL) and small, dense structures (SDS), alongside building presence. The model was trained on automatically generated reference data using building footprint morphometrics and clustering, and its outputs were validated through community-sourced annotations obtained via participatory action research. The results demonstrate the potential of high-resolution satellite imagery for mapping ISL (F1 80.90) and SDS (F1 78.73). Nonetheless, further research is required on the geographic transferability of the proposed method.Publication Open Access The SPACE4ALL project: accounting for the hazard exposure of the urban poor: combining remote sensing and citizen science(IEEE, 2025-07-16) Trento Oliveira, Lorraine; Campomanes, Enzo; Belgiu, Mariana; Dijkstra, Anne; Abascal, Ángela; Kuffer, Monika; Ingeniería; IngeniaritzaSlums and informal settlements are among the most common forms of urban development in Africa. These areas often lack essential infrastructure and services, face socioeconomic disparities, and are increasingly vulnerable to climate risks such as floods. The Space4All project aims to promote sustainable urban development by integrating advanced geospatial technologies with locally grounded approaches to analyze the intersection of livability and flood exposure in pilot cities in Ghana, Kenya, and Mozambique. To develop a scalable approach, we use open data such as Sentinel-2 satellite imagery. The methodology combines state-of-the-art AI models, Earth Observation data with Citizen-generated data collected via a custom app. The results highlight deprivation hotspots, revealing the intersection of spatial inequalities and flood exposure. Flood exposure is assessed through a comprehensive approach that integrates local knowledge gathered from workshops in informal settlements with flood models and historical rainfall data. This research provides actionable insights for urban planners, policymakers, and NGOs to prioritize targeted interventions and investments, fostering resilience through community-driven approaches.Publication Open Access Towards a spatial measure of SDG 11.1.1: open data for urban deprivation mapping(IEEE, 2025-07-16) Veeravalli, Sai Ganesh; Campomanes, Florencio V; Hafner, Sebastian; Georganos, Stefanos; Kuffer, Monika; Friesen, John; Thomson, Dana R.; Ndugwa, Robert; Mwaniki, Dennis; Abascal, Ángela; Elias, Peter; Morakinyo, Tobi Eniolu; Pedrassoli, Julio; Oliveira, Gabriel de; Boanada-Fuchs, Anthony; Zerjav, Boris; D'Attoli, Juan Manuel; Ingeniería; IngeniaritzaUrban deprivation mapping is critical for addressing inequalities and achieving Sustainable Development Goal (SDG) 11.1.1, which focuses on ensuring access to adequate housing and services in urban areas. This study introduces a geospatial framework to operationalize previously conceptualized urban Domains of Deprivation related to unplanned urbanization, limited infrastructure, and limited services within city segments at the city-scale. Leveraging open, global datasets, including Google's V3 building footprints and 2.5D building heights, the model assigns deprivation scores (ranging from 0 to 6) based on binary thresholds derived from median values. Validation against reference slum boundaries provided by the IDEAMAPS network achieved an F1- score of 0.45 for high-deprivation areas. The results highlight the spatial distribution of deprivation across Nairobi and demonstrate the reliability of dense building indicators for identifying informal settlements. The framework demonstrates computational efficiency, enabling citywide analysis using accessible resources, and highlights its potential to inform urban planning and targeted interventions through scalable geospatial methodologies aligned with SDG 11.1.1.Publication Open Access Innovative data solutions for inclusive cities: the IDEAtlas user portal(ISPRS, 2025-05-25) Tareke, Bedru; Silva Filho, Paulo; Persello, Claudio; Kuffer, Monika; Maretto, Raian V.; Wang, Jiong; Abascal, Ángela; Pillai, Priam; Singh, Binti; D'Attoli, Juan Manuel; Kabaria, Caroline; Pedrassoli, Julio; Brito, Patricia; Elias, Peter; Villaseñor, Elio Atenógenes; Ramírez Santiago, Andrea; Mulyana, Wahyu; Pratomo, Jati; Leska, Ruth; Streitenberger, Jan; Mwaniki, Dennis; Thomson, Dana R.; Ingeniería; IngeniaritzaAddressing the challenge of mapping deprived urban areas (DUAs) globally requires both technical innovation and user engagement. The IDEAtlas project developed a novel approach to monitor DUAs by combining advanced Earth Observation (EO) technologies with a user-centered design. Central to this is our IDEAtlas User Portal, a data platform that provides scalable, accessible, and participatory mapping solutions in support of Sustainable Development Goal (SDG) 11.1.1. The portal provides outputs from a custom Multi-Branch Convolutional Neural Network (MB-CNN) model trained on freely available Sentinel-1 and Sentinel-2 data, enriched with ancillary open datasets such as building footprints. Presently, the portal offers binary settlement maps, with future plans to include deprivation severity indices, and multi-temporal urban growth maps for the period 2019 to 2023. A unique feature of the IDEAtlas platform is its two-tier access model: an open section offering 100 by 100 m gridded outputs for public use, and a protected section for sensitive, city-level data. In the protected section, users can validate outputs. The user validation is an essential element of our Living Labs and is done in the form of continuous stakeholder collaboration. Through Living Labs and iterative user feedback across eight global cities, the portal has demonstrated how involving local governments, NGOs, and community organizations can enhance data quality, relevance, foster ownership, and empower decision-making. Early user engagements, such as the update of Argentina's RENABAP informal settlement registry, highlight the portal's operational value. By coupling technological scalability with participatory validation. Thus, the IDEAtlas User Portal represents a significant step toward inclusive, evidence-based urban planning and policymaking.Publication Open Access Using low-cost sensors and citizen science: assessing thermal inequality in African slums(ISPRS, 2025) Sampson, Sally Ama; Abascal, Ángela; Wang, Jiong; Vanhuysse, Sabine; Rodríguez Carreño, Ignacio; García Ruiz, Ignacio; Kuffer, Monika; Ingeniería; IngeniaritzaUrban heat exposure is intensifying due to climate change and urbanisation, with disproportionate impacts on vulnerable populations. Unfortunately, many urban areas, particularly informal settlements, lack sufficient data for detailed analysis to understand these impacts. Traditional air temperature measurement methods¿such as meteorological stations¿are sparsely distributed in African cities, typically located on city outskirts (e.g., airports), and fail to capture localized temperature variations. This study explores the use of low-cost sensors and citizen science initiatives to measure air temperature with higher spatial resolution in informal and surrounding formal settlements. A two-stage process is employed to evaluate data quality: first, statistically assessing biases in low-cost sensor (LCS) measurements, and second, employing Monte Carlo simulations to quantify uncertainties. The resulting data reveals significant temperature differences between informal settlements and surrounding formal areas, with informal settlements consistently exhibiting higher temperatures. This approach not only highlights the value of low-cost sensors and citizen science in generating high-resolution temperature data but also provides insights into thermal inequalities between different urban environments.Publication Open Access Towards an indicator-based morphological informality model for Sub-Saharan Africa using open building footprint and road data (Version 1)(ISPRS, 2025) Hafner, Sebastian; Zhao, Qunshan; Abascal, Ángela; Comerio de Paulo, Manuella; Tregonning, Grant; Middleton, Alexandra; Shonowo, Adenike; Kuffer, Monika; Engstrom, Ryan; Thomson, Dana R.; Onyambu, Francis C.; Kabaria, Caroline; Elias, Peter; Odulana, Oluwatoyin; Alugbin, Bunmi; Baruwa, Kehinde; Albuquerque, João Porto de ; Ingeniería; IngeniaritzaThis study addresses the challenge of accurately mapping informal settlements, which are home to over a billion people globally. Current maps often simplify these areas into binary categories, ignoring the nuanced dimensions of deprivation. The research focuses on 'unplanned urbanization', a key domain in informal settlement mapping, and proposes a method to classify morphological informality into three deprivation levels (low, medium, and high) based on two subdomains: small, dense structures (SDS) and irregular settlement layouts (ISL). The methodology involves analyzing building footprints and road network data using urban morphometrics, clustering these metrics into subdomains with k-means, and validating results with community-sourced reference data. Tested in Nairobi, Kenya, and Lagos, Nigeria, the model achieves good performance (F1 > 65 for indicator maps) but faces challenges in the medium informality class, particularly in Nairobi, where community feedback diverges significantly. Despite an overall accuracy of 48 % for Nairobi and 60 % for Lagos, the model offers a framework for continuous improvement. This work highlights the value of integrating local perspectives into mapping efforts and provides a scalable, transferable approach for identifying levels of morphological informality.Publication Open Access Robust tuning of cascaded PI controllers for a grid-forming DFIG wind turbine(IEEE, 2025-11-25) El Hamzaoui, Ismail; López Taberna, Jesús; Samanes Pascual, Javier; Gubía Villabona, Eugenio; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISCThis paper presents a systematic tuning method for cascaded PI controllers in Grid-Forming (GFM) Doubly- Fed Induction Generator (DFIG) wind turbines. The approach emphasizes control parameter range selection as key to achieving robust stability. Unlike reviewed methods that rely on arbitrarily defined search spaces for the controller gains, this approach preconditions control parameters calculating them based on achievable open-loop cutoff frequency and phase margin ranges. Further refinement is achieved by filtering the calculated search space based on closed-loop stability across varying grid strengths and rotational speeds. This ensures robustness across multiple operating conditions. Optimized settling time and overshoot is found using a set of RMSE-based cost functions. Tuning and performance validation are conducted using a full-order smallsignal model and EMT simulations in Simulink.Publication Open Access Exploring the relation of livability mapping and flood exposure analysis by combining remote sensing and citizen science(ISPRS, 2025-05-25) Campomanes, Florencio V.; Trento Oliveira, Lorraine; Belgiu, Mariana; Abascal, Ángela; Dijkstra, Anne; Kuffer, Monika; Ingeniería; IngeniaritzaEnvironmental hazards are key determinants of urban liveability, shaping the safety, health, and resilience of residents. This study investigates the intersection of urban livability and flood exposure by integrating remote sensing, citizen science, and AI-driven analysis across three African countries: Ghana, Kenya, and Mozambique. Using Sentinel-1 satellite imagery, open geospatial datasets, and advanced deep learning techniques, a citizen-derived perceived livability index was created which was then combined with rapid flood exposure modelling through FastFlood. The results reveal that areas with the lowest livability scores -characterized by poor housing conditions, limited service access, and minimal green spaces- are also consistently the most exposed to frequent and severe flooding. In Nairobi, for instance, approximately 35% of built-up areas are flood-prone, with informal settlements like Kibera and Mathare facing disproportionate risks. Citizen science efforts validated the flood models, underscoring the critical role of local knowledge in capturing fine-scale flood dynamics invisible to remote sensing alone. The project demonstrates that liveability and environmental risk are deeply interrelated, and contribute to worsening urban vulnerability. By combining community mapping with scalable Earth Observation methods, this work delivers actionable methods for urban planners, humanitarian organizations, and local policymakers. Our results stress the importance of planning strategies that prioritize investments in flood mitigation, nature-based solutions, and resilient infrastructure for the most at-risk communities. Such communities are often omitted in official data. The needs and views of such vulnerable communities need to be included in supporting sustainable and inclusive urban development under increasing climate pressures.Publication Open Access Rayleigh signature interrogation in time-domain DAS sensors using the short-frequency Fourier transform(SPIE, 2025-05-22) Sharif, Vahid; Sagüés García, Mikel; Loayssa Lara, Alayn; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISCWe present a general method to determine the dependence of Rayleigh backreflection in an optical fiber on position and optical frequency. It is based on applying the so-called short-frequency Fourier transform to signals obtained from coherent optical time-domain reflectometry (COTDR) measurements. The proposed method enables the implementation of distributed acoustic sensors (DAS) with high linearity, spatial resolution, and measurement frequency, while being immune to signal fading. Additionally, the technique is compatible with both conventional COTDR setups and those employing pulse compression, including phase-coded compression waveforms. We experimentally demonstrate the technique with DAS measurements of a 50-km sensing fiber, achieving a 2-m spatial resolution and a sensitivity of 137 p epsilon/root Hz using a pulse-compression COTDR with a P4 phase-coded compression waveform.Publication Open Access Linearizing the mode transition in LPFG sensors with metal and dielectric thin films(SPIE, 2025-05-22) González Salgueiro, Lázaro José; Del Villar, Ignacio; Corres Sanz, Jesús María; Matías Maestro, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio IngeniaritzaLong Period Fiber Gratings (LPFGs) offer a versatile platform for sensing applications due to their ability to couple core and cladding modes through periodic refractive index modulation, which makes the device sensitive to changes in the surrounding refractive index (SRI). The sensitivity can be enhanced through mechanisms such as the dispersion turning point and mode transition. However, the performance is non-linear. To avoid this, here we explore the less-examined relationship between mode transition and lossy mode resonances (LMRs), both of which occur within the same thin-film thickness range. By depositing a gold layer followed by a high refractive index TiO2 layer, we obtained a highly sensitive and linear performance, while aiming at minimizing the bandwidth of the attenuation bands. Two LPFGs with different modulation indices were fabricated and their spectral response to varying TiO2 thicknesses was monitored. The results demonstrated that LPFGs can achieve a sensitivity to the thin film thickness variation of 9 nm/nm, similar to LMR-based sensors, and a linear evolution as a function of thickness, with the possibility to improve the bandwidth. This improvement could boost the applicability of LPFGs in domains such as environmental sensing and biosensing, with the potential for further improvement through thin film refinement and optimization of LPFG parameters.Publication Open Access Three-state modulation strategy for capacitor charging in modular high-voltage pulse generator(IEEE, 2025) Velasquez, Sofia A.; Guzman, Johan I.; Pérez, Marcelo A.; Samanes Pascual, Javier; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio IngeniaritzaThe high-voltage pulse generator is a crucial component for performing the electroporation process required in water treatment. This paper presents a three-state modulation for high-voltage pulse generator based on a modular converter structure. The converter consists of modular submodules connected in series, each comprising a half-bridge, a capacitor, and interconnecting diodes and inductors for series/parallel operation. The system eliminates the need for high-voltage switches and ensures a rapid dynamic response during the discharge process due to the absence of arm inductance. The proposal modulation allows to control the charging current, which is dependent on interconnecting inductors and switching frequency. The modulation technique is proposed, analyzed, and validated through simulation results.Publication Open Access Role of thin film refractive index contrast in the design and performance of nano-photonic crystal D-shaped fiber devices for label-free biosensing(SPIE, 2025-05-22) Del Villar, Ignacio; González-Valencia, Esteban; Kwietniewski, Norbert; Burnat, Dariusz; Borri, Claudia; Singh, Rukmani; Dabagh, Shadab; Armas, Dayron; Pitula, Emil; Janik, Monika; Matías Maestro, Ignacio; Giannetti, Ambra; Torres, Pedro; Smietana, Mateusz; Chiavaioli, Francesco; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISCAchieving a high figure of merit alongside exceptional sensitivity is critical for advancing optical biosensors capable of ultra-low limits of detection. In this work, we investigate the performance of D-shaped single-mode fiber devices coated with 1D photonic crystal stacks. These nano-assembled layers, composed of alternating high- and low-refractive-index (RI) materials, enable the excitation of Bloch surface waves (BSWs). By systematically varying the RI contrast between the layers, we demonstrate that while a moderate increase in RI contrast improves sensitivity and narrows the full width at half maximum (FWHM) of the BSW resonance, the sensitivity tends to stabilized as we further increase the RI contrast, while the FWHM still can be pushed towards a higher FoM. Real-world applicability is validated through the detection of immunoglobulin G (IgG) at record-low concentrations of 70 aM, leveraging the solution as a versatile, operando, high-performance biosensing platform.Publication Open Access Reliable, doped hybrid xerogel-based optical fibre sensor for pH monitoring for industry(SPIE, 2025-05-22) Rosales Reina, María Beatriz; Whittaker, N.; López Torres, Diego; Elosúa Aguado, César; Reinoso, Santiago; Sun, Tong; Grattan, Kenneth T. V.; Garrido Segovia, Julián José; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaA new optical fibre pH sensor has been developed based on incorporating the pH indicator in a hybrid siliceous xerogel. Here the hydrophobic siliceous materials were fabricated using the sol-gel method, employing an optimal percentage of organic precursor moieties, propyltriethoxysilane:tetraetoxysilane, then doping it with three different pH indicators (phenolphthalein, bromophenol blue and cyanidin blue), to create three different optical fibre sensor systems (5pTEOSPH, 5pTEOSBF and 5pTEOSCB). These pH sensors exhibit important features needed by industry: fast response times, minimal dye leaching, good stability, a high level of reproducibility, and reversibility in response. Sensors of this type have a number of important potential uses in different applications in industry today.Publication Open Access Time-transformed spectral analysis for multiparametric sensing using a single antiresonant interferometer(SPIE, 2025-05-22) Jaso Gallego, Isabel; Sánchez González, Arturo; Bravo Acha, Mikel; Pérez Herrera, Rosa Ana; Leandro González, Daniel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISCThis work explores the potential of spectral composition analysis in the time-transformed domain for multiparametric sensing using a single in-line hollow-core interferometer. By effectively distinguishing between antiresonance guidance and Fabry Perot-induced contributions, this approach allows simultaneous measurement of two independent parameters. The sensor, featuring polyimide coating, was characterized during humidity cycles at varying temperatures by monitoring phase variations in the transformed domain. The distinct sensitivities of antiresonance and Fabry-Perot components allowed the determination of temperature and relative humidity using a multiparametric linear model, achieving good agreement with experimental results and underscoring its robustness for multiparametric sensing applications.Publication Open Access Interferometric optical fiber sensor with a polyoxometalate-doped xerogel for the selective detection of ammonia(SPIE, 2025-05-22) Hernández López, Claudia; Rosales Reina, María Beatriz; Reinoso, Santiago; Garrido Segovia, Julián José; López Torres, Diego; Elosúa Aguado, César; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaThis study presents the development and evaluation of an interferometric optical fiber sensor (I-OFS) based on a Single Mode Fiber-No Core Fiber-Single Mode Fiber (SMF-NCF-SMF) structure and functionalized with a silica xerogel doped with a titanium (IV)-containing polyoxomolibdate (GeMoTi). The behavior of the sensor was tested under saturated atmospheres of ammonia, water, and various volatile organic compounds (VOCs), including ethanol, acetone, and toluene. The response is characterized in terms of wavelength shifts, which are highlightable for ammonia due to its strong chemical interactions with the doped xerogel. The response and recovery times were evaluated for each analyte, pointing out ammonia as the compound with the fastest and most stable detection performance. These results reinforce the hypothesis of using GeMoTi-doped xerogels to enhance the selectivity of I-OFS for the detection of closely related amines.Publication Open Access Polarization-switched fiber optic ring laser for L-band multiwavelength remote sensing applications(SPIE, 2025-05-22) Pérez Herrera, Rosa Ana; Janices Chamizo, Iñaki; San Miguel Zarraluqui, Uxue; Salinas Anguiano, Álvaro; Sánchez González, Arturo; Erro Betrán, María José; Tainta Ausejo, Santiago; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaThis work presents the experimental demonstration of a three-channel remote sensor that operates in the L-band. It is based on a fiber ring laser cavity, formed by a semiconductor optical amplifier and three fiber Bragg gratings used both for the selection of the operating wavelengths and the sensing. A polarization-controller allows the activation of one, two or the three emission wavelengths simultaneously. The sensing elements can be situated in a remote localization, without compromising the temperature sensitivity of the experimental setup. To validate this functionality, a 25 km standard single-mode fiber optic reel is incorporated between the FBG-based sensors and the cavity, demonstrating the system's ability to perform long-range sensing while preserving signal integrity and operational reliability.