Open Access
Comparative study of ring and random cavities for fiber lasers
(Optical Society of America, 2014) Fernández Vallejo, Montserrat; Rota Rodrigo, Sergio; López-Amo Sáinz, Manuel; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
An experimental comparison of three fiber laser structures with the same Raman gain medium is presented in order to establish the main pros and cons of each basic scheme. The first fiber laser is based on a hybrid ring–random fiber laser, the second one is a pure ring fiber laser, and the last one is a random fiber laser. Several aspects have been taken into account in the study. First, from the optical point of view, the parameters of interest compared are output power, lasing threshold, slope efficiency, power fluctuations, and the longitudinal modes have been analyzed. Second, the possible utilization of fiber lasers in digital modulated optical communication systems is also studied.
Open Access
Simultaneous measurement of strain and temperature using a single emission line
(IEEE / OSA, 2015) Leandro González, Daniel; Ams, Martin; López-Amo Sáinz, Manuel; Sun, Tong; Grattan, Kenneth T. V.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work, we present and demonstrate a novel sensor system for simultaneous measurement of strain and temperature through a unique combination of a long period grating (LPG) and a fiber laser based on a fiber Bragg grating (FBG). In order to achieve this, a new erbium doped fiber laser (EDFL) structure is created, showing an optical signal-to-noise ratio (OSNR) of 55 dB and a peak power measured on the OSA between -5 and 0 dBm. The strain and the temperature information can be obtained by using a unique emission line through monitoring both the fiber laser wavelength shift and the change of the power level, both of which showing a clear linear behavior.
Open Access
Compact optical fiber lasers and optical fiber sensors assisted by femtosecond laser inscription of plane-by-plane FBGs
(Optica, 2020) Roldán Varona, Pablo; Pallarés Aldeiturriaga, D.; Rodríguez Cobo, Luis; Pérez Herrera, Rosa Ana; Bravo Acha, Mikel; López-Amo Sáinz, Manuel; López Higuera, José Miguel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
Development of a high temperature sensor based on optical fiber l aser generated from a cavity of reduced dimensions (43 mm) in Er-doped fiber. The mirror FBGs have been inscribed with femtosecond laser using the slit beam technique (Pl-b-Pl).
Open Access
Sistema de interrogación multi-sensor basado en multiplexación en longitud de onda y tiempo
(SEDOPTICA, 2021) Bravo Acha, Mikel; Leandro González, Daniel; Pérez González, Asier; López-Amo Sáinz, Manuel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
En este trabajo se propone un sistema de interrogación versátil y económico basada en la generación de pulsos empleando la modulación directa de diodos láser DFB. Se ha demostrado una resolución en longitud de onda de 1 pm para una separación de sensores de 600m. La validación del interrogador se ha llevado a cabo monitorizando una red de sensores de 26 km de longitud que incluye redes de difracción de Bragg, reflectores y un interferómetro Fabry-Pérot.
Open Access
Virtual FBGs using saturable absorbers for sensing with fiber lasers
(MDPI, 2018) Rodríguez Cobo, Luis; Pérez Herrera, Rosa Ana; Quintela, M. A.; Ruiz Lombera, Rubén; López-Amo Sáinz, Manuel; López Higuera, José Miguel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
The spectral narrowing of Fiber Bragg Gratings (FBGs) introduced by unpumped Er-doped fiber (EDF) was analyzed for fiber lasers (FL). Owing to spatial hole burning (SHB), the spectral response of a virtual FBG can be employed for narrowing the band pass filter employed to determine the lasing wavelength of laser cavities. A common FL was mounted to analyze the spectral stability of the method, and a FL sensor for strain and temperature measurements was experimentally characterized to determine the stability of the narrowing effect achieved by the unpumped EDF, which acts as a virtual FBG. The results exhibited remarkably good narrowing effects of the spectral response of uniform FBGs.
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
Ultra-long (275 km) random distributed feedback fiber laser for remote sensor monitoring
(Optical Society of America, 2018) Miguel Soto, Verónica de; Leandro González, Daniel; 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
An interferometric sensor located 275 km away from the monitoring station has been interrogated by a double-pumped random distributed feedback fiber laser, reaching the longest distance in fiber optic remote sensing reported up to date.
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.
Open Access
Switchable erbium doped fiber ring laser system for temperature sensors multiplexing
(IEEE, 2013) Rota Rodrigo, Sergio; Rodríguez Cobo, Luis; Quintela, M. A.; López Higuera, José Miguel; López-Amo Sáinz, Manuel; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper a proof of concept of a switchable erbium doped fiber ring laser (EDFRL) system, demonstrated for temperature sensors multiplexing, was carried out showing a high linearity and a sensitivity of 1.55 GHz/°C. The system is based on the detection in the electrical domain of the resulting beat signal of two different laser lines generated by an EDFRL that operates in single longitudinal mode regime (SLM). The SLM operation is achieved by the use of phase shift fiber Bragg gratings (PSFBGs) with ultra-narrow bandwidths (BW) of 6 pm. Two Independent cavities for the reference signal and sensor signal generation are used to avoid the wavelength competition and to improve the stability. This configuration allows the control of the temperature operation point of the system by adjusting the temperature in the reference side.
Open Access
Optimization of the available spectrum of a WDM sensors network using a mode locked laser
(IEEE / OSA, 2015) Fernández Vallejo, Montserrat; Ardanaz, Diego; López-Amo Sáinz, Manuel; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
This work experimentally proposes a new interrogation method which consists on the combination of the information given by both domains: time and frequency. On the one hand, the sensor information is obtained in the frequency domain as usual and, on the other hand, the detection of the different pulses generated through mode locking allows the identification of each FBG. It has been proved that FBGs spaced less than 0.15 nm can be interrogated. The sensor network based on simple ring Erbium doped fiber laser using the FBGs, located in a serial configuration, as wavelength selective reflectors for the lasing structure, acting them also as the sensing transducers elements.