Now showing items 1-9 of 9

    • 250 km ultra long remote sensor system based on a fiber loop mirror interrogated by an OTDR 

      Bravo Acha, Mikel Upna; Baptista, José Manuel; Santos, José Luís; López-Amo Sáinz, Manuel Upna; Frazão, Orlando (Optical Society of America, 2011)   Artículo / Artikulua  OpenAccess
      A 253 km ultra long remote displacement sensor system based on a fiber loop mirror interrogated by a commercial OTDR is proposed and experimentally demonstrated. The use of a fiber loop mirror increases the signal to noise ...
    • ECOAL project: delivering solutions for integrated monitoring of coal-related fires supported on optical fiber sensing technology 

      Ribeiro, Joana; Viveiros, Duarte; Ferreira, João; López Gil, Alexia; Domínguez López, Alejandro; Martins, Hugo F.; Pérez Herrera, Rosa Ana Upna; López Aldaba, Aitor Upna; Duarte, Lia; Rodrigues Pinto, Ana Margarida Upna; Martín López, Sonia; Baierl, Hardy; Jamier, Raphael; Rougier, Sébastien; Auguste, Jean-Louis; Teodoro, Ana Cláudia; Gonçalves, José Alberto; Esteban, Óscar; Santos, José Luís; Roy, Philippe; López-Amo Sáinz, Manuel Upna; González Herráez, Miguel; Baptista, José Manuel; Flores, Deolinda (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      The combustion of coal wastes resulting from mining is of particular environmental concern, and the importance of proper management involving real-time assessment of their status and identification of probable evolution ...
    • Experimental and numerical characterization of a hybrid Fabry-Perot cavity for temperature sensing 

      López Aldaba, Aitor Upna; Rodrigues Pinto, Ana Margarida Upna; López-Amo Sáinz, Manuel Upna; Frazão, Orlando; Santos, José Luís; Baptista, José Manuel; Baierl, Hardy; Auguste, Jean-Louis; Jamier, Raphael; Roy, Philippe (MDPI, 2015)   Artículo / Artikulua  OpenAccess
      A hybrid Fabry-Pérot cavity sensing head based on a four-bridge microstructured fiber is characterized for temperature sensing. The characterization of this cavity is performed numerically and experimentally in the L-band. ...
    • 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 ...
    • Micro-displacement sensor based on a hollow-core photonic crystal fiber 

      Rodrigues Pinto, Ana Margarida Upna; López-Amo Sáinz, Manuel Upna; Baptista, José Manuel; Santos, José Luís; Frazão, Orlando (MDPI, 2012)   Artículo / Artikulua  OpenAccess
      A sensing head based on a hollow-core photonic crystal fiber for in-reflection measurement of micro-displacements is presented. The sensing structure takes advantage of the multimodal behavior of a short segment ...
    • Micro-displacement sensor combined with a fiber ring interrogated by an optical time-domain reflectometer 

      Bravo Acha, Mikel Upna; Baptista, José Manuel; Santos, José Luís; López-Amo Sáinz, Manuel Upna; Frazão, Orlando (IEEE, 2014)   Artículo / Artikulua  OpenAccess
      A micro-displacement sensing head based on two aligned cleaved fibers inserted into an optical fiber ring and interrogated by an OTDR is presented. The sensor configuration is characterized for measuring both longitudinal ...
    • Multiwavelength Raman fiber lasers using Hi-Bi photonic crystal fiber loop mirrors combined with random cavities 

      Rodrigues Pinto, Ana Margarida Upna; Frazão, Orlando; Santos, José Luís; López-Amo Sáinz, Manuel Upna (IEEE / OSA, 2011)   Artículo / Artikulua  OpenAccess
      Different multiwavelength Raman fiber lasers based on a hybrid cavity set-up are proposed. The lasing schemes are based in highly birefringent photonic crystal fiber loop mirrors combined with random cavities. The Hi-Bi ...
    • Sensitivity improvement of a humidity sensor based on silica nanospheres on a long-period fiber grating 

      Viegas, Diana; Goicoechea Fernández, Javier Upna; Santos, José Luís; Araújo, Francisco Moita; Ferreira, Luis Alberto; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna (MDPI, 2009)   Artículo / Artikulua  OpenAccess
      This work addresses a new configuration that improves the sensitivity of a humidity sensor based on a long-period fiber grating coated with a SiO(2)-nanospheres film. An intermediate higher refractive index overlay, ...
    • Simultaneous measurement of strain and temperature based on clover microstructured fiber loop mirror 

      Pérez Herrera, Rosa Ana Upna; André, R. M.; Silva, S. F.; Becker, M.; Schuster, K.; Kobelke, J.; López-Amo Sáinz, Manuel Upna; Santos, José Luís; Frazão, Orlando (Elsevier, 2015)   Artículo / Artikulua  OpenAccess
      In this work, two all-fiber loop mirrors using a clover microstructured fiber for the simultaneous measurement of temperature and strain are presented. The sensing heads are formed by a short piece of clover microstructured ...