Open Access
Internal modulation of a Random fiber laser
(Optical Society of America, 2013) Bravo Acha, Mikel; Fernández Vallejo, Montserrat; López-Amo Sáinz, Manuel; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
A characterization of a modulated random mirror laser has been experimentally carried out. Unlike conventional internally modulated fiber lasers, no distortion of the modulating frequency or self-mode-locking effects were measured. The behavior of the laser using pulsed and analog modulation up to 12 GHz is shown.
Open Access
In-field torsion measurements on solar trackers using fiber optic sensors
(Optica, 2020) Leandro González, Daniel; Bravo Acha, Mikel; Júdez Colorado, Aitor; Mariñelarena Ollacarizqueta, Jon; Falcone Lanas, Francisco; Loayssa Lara, Alayn; López-Amo Sáinz, Manuel; Jiménez, S.; Achaerandio, Álvaro; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Gobierno de Navarra / Nafarroako Gobernua
In-field torsion measurements on solar trackers using fiber Bragg gratings are presented. 45 FBG sensors have been deployed in an operational solar energy plant to study the mechanical response of the structure to wind.
Open Access
Optical fiber sensor for water velocity measurement in rivers and channels
(Nature Research, 2024) Rodríguez Rodríguez, Armando; Diéguez Elizondo, Pedro; Urroz Unzueta, José Carlos; Bravo Acha, Mikel; López Rodríguez, José Javier; López-Amo Sáinz, Manuel; Ingeniería; Ingeniaritza; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
In this work, optical fiber Bragg grating sensors were used to measure water velocity and examine how it was distributed in open channels. Several types of coatings were incorporated into the design of the sensors to examine their effects on the strain that the fibers experienced as a result of the water flow. Due to their low elastic coefficient, which reduced the hysteresis, the results indicated that the aluminum- and acrylate-coated fibers had the best performance. ANSYS-CFX V2020 R2 software was used to model the strain encountered by the fibers under various flow rates to assess the performance of the FBG sensors. The calculations and actual data exhibited good convergence, demonstrating the accuracy of the FBG sensors in determining water velocity. The study illustrated the usability of the proposal in both scenarios by contrasting its application in rivers and channels.
Open Access
WDM and TDM interrogation by sequentially pulsing direct modulated DFBs
(Optica, 2020) Pérez González, Asier; Bravo Acha, Mikel; Leandro González, Daniel; Pérez Herrera, Rosa Ana; López-Amo Sáinz, Manuel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC
A new versatile and cost-effective interrogation system by pulsing direct modulated (DM) DFB laser diodes is proposed. 1 pm wavelength resolution and 600 m sensor spacing is demonstrated by sequentially pulsing a DM DFB.
Open Access
Traffic monitoring based on FBG sensor arrays in asphalt structures
(Optica, 2020) Bravo Acha, Mikel; Leandro González, Daniel; Bravo Acha, A.; Bravo Navas, M.; Mitxelena, J. R.; Martínez Mazo, J. J.; Camarero, E.; López-Amo Sáinz, Manuel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We evaluate the capabilities of optical fiber sensors to measure traffic flow, speed, weight estimation and pavement degradation. The proper operation of the system has been proved 3.5 years after the installation in a metropolitan road.
Open Access
Distributed humidity sensor for moisture-front monitoring in soils
(Optica, 2020) Leandro González, Daniel; Delgado Zabala, Oihane; López Rodríguez, José Javier; Bravo Acha, Mikel; López-Amo Sáinz, Manuel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
In this contribution, high spatial resolution distributed humidity sensing was demonstrated for moisture-front monitoring in soils by using polyimide coated optical fiber.
Open Access
Enhanced optical fiber lasers and optical fiber sensors assisted by micro-drilled optical fibers
(Optica, 2020) Pérez Herrera, Rosa Ana; Bravo Acha, Mikel; Roldán Varona, Pablo; Leandro González, Daniel; Rodríguez Cobo, Luis; López Higuera, José Miguel; López-Amo Sáinz, Manuel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
Enhanced OFS assisted by micro-drilled optical fibers acting as mirrors are demonstrated. Strain sensitivity improved more than one order of magnitude in comparison with FBG sensors using a 50 μm-waist micro-drilled taper as distributed reflector.