Now showing items 215-234 of 572

    • Fabrication of Bragg gratings on the end facet of standard optical fibers by sputtering the same material 

      Ascorbe Muruzabal, Joaquín Upna; Corres Sanz, Jesús María Upna; Del Villar, Ignacio Upna; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna (IEEE, 2016)   Artículo / Artikulua  OpenAccess
      A sputtering process has been applied to deposit quarter-wavelength stacks on the end facet of cleaved optical fibers by using only one sputtering target. Standard multimode optical fibers were used as substrates to fabricate ...
    • Fe-rich ferromagnetic wires for self-sensing materials 

      Liberal Olleta, Íñigo Upna; Ederra Urzainqui, Íñigo Upna; Gonzalo García, Ramón Upna (IEEE, 2012)   Artículo / Artikulua  OpenAccess
      The possibility of using Fe-rich wires in mechanical stress self-sensing materials is investigated. To this end, a retrieval technique aimed to characterize the high-frequency magnetoimpedance effect in ferromagnetic wires ...
    • Fiber cavity ring down and gain amplification effect 

      Silva, Susana; Magalhães, Regina; Pérez Herrera, Rosa Ana Upna; López-Amo Sáinz, Manuel Upna; Marques, M. B.; Frazão, Orlando (Springer Nature, 2016)   Artículo / Artikulua  OpenAccess
      The effect of an erbium-doped fiber amplifier (EDFA) placed inside the fiber ring of a cavity ring down (CRD) configuration is studied. The limitations and advantages of this configuration are discussed, and the study of ...
    • A fiber optic ammonia sensor using a universal pH indicator 

      Rodríguez Rodríguez, Adolfo Josué; Ruiz Zamarreño, Carlos Upna; Matías Maestro, Ignacio Upna; Arregui San Martín, Francisco Javier Upna; Cruz, René; May Arrioja, Daniel A. (MDPI, 2014)   Artículo / Artikulua  OpenAccess
      A universal pH indicator is used to fabricate a fiber optic ammonia sensor. The advantage of this pH indicator is that it exhibits sensitivity to ammonia over a broad wavelength range. This provides a differential response, ...
    • Fiber optic multiple-wavelength filter based on one dimensional photonic bandgap structures with defects 

      Del Villar, Ignacio Upna; Matías Maestro, Ignacio Upna; Arregui San Martín, Francisco Javier Upna (IEEE, 2004)   Artículo / Artikulua  OpenAccess
      In this paper, a theoretical analysis is given of an optical fiber multiple-wavelength tunable filter based on a onedimensional (1-D) photonic bandgap (PBG) structure with four defects. To understand the positioning of ...
    • Fiber-optic lossy mode resonance sensors 

      Arregui San Martín, Francisco Javier Upna; Del Villar, Ignacio Upna; Corres Sanz, Jesús María Upna; Goicoechea Fernández, Javier Upna; Ruiz Zamarreño, Carlos Upna; Elosúa Aguado, César Upna; Hernáez Sáenz de Zaitigui, Miguel Upna; Rivero Fuente, Pedro J. Upna; Socorro Leránoz, Abián Bentor Upna; Urrutia Azcona, Aitor Upna; Sánchez Zábal, Pedro Upna; Zubiate Orzanco, Pablo Upna; López Torres, Diego Upna; Acha Morrás, Nerea de Upna; Matías Maestro, Ignacio Upna (Elsevier, 2014)   Contribución a Congreso / Biltzarrerako ekarpena  OpenAccess
      In the last 4 years, experimental evidences about the potential use of optical sensors based on Lossy Mode Resonances (LMR) have been presented in the literature. These LMR sensors have some similarities with Surface ...
    • Fiber-optic nanorefractometer based on one-dimensional photonic-bandgap structures with two defects 

      Del Villar, Ignacio Upna; Matías Maestro, Ignacio Upna; Arregui San Martín, Francisco Javier Upna (IEEE, 2004)   Artículo / Artikulua  OpenAccess
      A theoretical analysis of a fiber-optic photonic- bandgap (PBG)-based nanorefractometer is presented. Changes up to 11.2 dB in the optical output power in an index of refraction range of 1.7 with a sensitivity of 1.5 ...
    • Fisiopatología y técnicas de registro de los movimientos oculares 

      Gila Useros, Luis; Villanueva Larre, Arantxa Upna; Cabeza Laguna, Rafael Upna (Gobierno de Navarra, 2009)   Artículo / Artikulua  OpenAccess
      En el control de la motilidad ocular intervienen varios sistemas funcionales. Los reflejos vestíbulo-oculares y optocinéticos son respuestas automáticas para compensar los movimientos de la cabeza y del entorno visual y ...
    • Focus on terahertz plasmonics 

      Rahm, Marco; Nahata, Ajay; Akalin, Tahsin; Beruete Díaz, Miguel Upna; Sorolla Ayza, Mario Upna (IOP Publishing, 2015)   Artículo / Artikulua  OpenAccess
      Plasmonics is one of the growing fields in modern photonics that has garnered increasing interest over the last few years. In this focus issue, the specific challenges concerning terahertz plasmonics have been addressed ...
    • Frailty assessment based on the instrumented version on the 30-s chair stand test 

      Millor Muruzábal, Nora Upna (2015)   Tesis doctoral / Doktoretza tesia  OpenAccess
      El objetivo de esta tesis es mejorar la evaluación de la capacidad funcional usando nuevos parámetros cinemáticos. Así, el personal clínico dispondrá de una serie de medidas objetivas y cuantificables para realizar sus ...
    • Frequency modulated continuous wave system for optical fiber intensity sensors with optical amplification 

      Pérez Herrera, Rosa Ana Upna; Frazão, Orlando; Santos, José Luís; Araújo, Francisco Moita; Ferreira, Luis Alberto; Baptista, José Manuel; López-Amo Sáinz, Manuel Upna (IEEE, 2009)   Artículo / Artikulua  OpenAccess
      We report on the use of erbium doped fiber (EDF) amplification to enhance a frequency modulated continuous wave (FMCW) technique for referencing optical intensity sensors located between two Bragg grating structures. The ...
    • Frequency responses and synthesis methods for advanced microwave applications 

      Lujambio Genua, Aintzane Upna (2014)   Tesis doctoral / Doktoretza tesia  OpenAccess
      En esta tesis, se han propuesto unmétodo de aproximación basado en técnicas de diseño de filtros digitales y una técnica de síntesis directa basada en scattering inverso, para proporcionar flexibilidad al proceso de ...
    • Frequency selective properties of coaxial transmission lines loaded with combined artificial inclusions 

      Falcone Lanas, Francisco Javier Upna; Gil Guruceaga, Javier Upna (Hindawi, 2014)   Artículo / Artikulua  OpenAccess
      The properties of a modified coaxial transmission line by periodic inclusions will be discussed. The introduction of split ring resonators, conductor stubs, air gaps, and combination of these gives rise to new frequency ...
    • Frequency-based energy management strategy for stand-alone systems with distributed battery storage 

      Urtasun Erburu, Andoni Upna; Barrios Rípodas, Ernesto Upna; Sanchis Gúrpide, Pablo Upna; Marroyo Palomo, Luis Upna (IEEE, 2015)   Artículo / Artikulua  OpenAccess
      Distributed generation is an attractive solution for stand-alone AC supply systems. In such systems, the installation of two or more energy-storage units is recommended for system redundancy and may also be required when ...
    • Fringe generation with non-uniformly coated long-period fiber gratings 

      Del Villar, Ignacio Upna; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna; Cusano, Andrea; Paladino, Domenico; Cutolo, Antonello (Optical Society of America, 2007)   Artículo / Artikulua  OpenAccess
      In this work, the spectral characteristics of non-uniform symmetrically ring shaped coatings deposited on long-period fiber gratings (LPFGs) have been theoretically and experimentally investigated. To optimize the ...
    • Frozen mode from hybridized extraordinary transmission and Fabry-Perot resonances 

      Beruete Díaz, Miguel Upna; Rodríguez Ulibarri, Pablo Upna; Pacheco-Peña, Víctor Upna; Navarro Cía, Miguel Upna; Serebryannikov, Andriy E. (American Physical Society, 2013)   Artículo / Artikulua  OpenAccess
      Frozen modes arising in stacked subwavelength hole arrays are studied in detail. Their origin is proved to be connected with the interaction between the extraordinary transmission resonance and the Fabry–Perot cavity mode. ...
    • Full three-dimensional isotropic transformation media 

      García Meca, Carlos; Ortuño Molinero, Rubén Upna; Martí, J.; Martínez, Alejandro (IOP Publishing, 2014)   Artículo / Artikulua  OpenAccess
      We present a method that enables the implementation of full three-dimensional (3D) transformation media with minimized anisotropy. It is based on a special kind of shape-preserving mapping and a subsequent optimization ...
    • Fully switchable multi-wavelength fiber lasers based on random distributed feedback for sensors interrogation 

      Bravo Acha, Mikel Upna; Miguel Soto, Verónica de Upna; Ortigosa Cayetano, Amaia; López-Amo Sáinz, Manuel Upna (IEEE / OSA, 2015)   Artículo / Artikulua  OpenAccess
      In this paper, the experimental study and characterization of a novel real-time switchable multi-wavelength fiber laser has been carried out. Two different gain materials, such as a 50 km SMF and a 2.5 km DCF fibers were ...
    • Fuzzy logic-based energy management system design for residential grid-connected microgrids 

      Arcos Avilés, Diego; Pascual Miqueleiz, Julio María Upna; Marroyo Palomo, Luis Upna; Sanchís Gúrpide, Pablo Upna; Guinjoan Gispert, Francesc (IEEE, 2018)   Artículo / Artikulua  OpenAccess
      This paper presents the design of a low complexity fuzzy logic controller of only 25-rules to be embedded in an energy management system for a residential grid-connected microgrid including renewable energy sources and ...
    • Gain dependence of measured spectra in coherent Brillouin optical time-domain analysis sensors 

      Mariñelarena Ollacarizqueta, Jon Upna; Urricelqui Polvorinos, Javier Upna; Loayssa Lara, Alayn Upna (SPIE, 2016)   Contribución a congreso / Biltzarrerako ekarpena  OpenAccess
      We report on the effects of large pump pulse powers on Brillouin optical time-domain analysis (BOTDA) sensors based on phase-modulated probe wave and coherent detection. It is found that the large Brillouin gain that comes ...