Open Access
Remote (250 km) fiber Bragg grating multiplexing system
(MDPI, 2011) Fernández Vallejo, Montserrat; Rota Rodrigo, Sergio; López-Amo Sáinz, Manuel; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
We propose and demonstrate two ultra-long range fiber Bragg grating (FBG) sensor interrogation systems. In the first approach four FBGs are located 200 km from the monitoring station and a signal to noise ratio of 20 dB is obtained. The second improved version is able to detect the four multiplexed FBGs placed 250 km away, offering a signal to noise ratio of 6-8 dB. Consequently, this last system represents the longest range FBG sensor system reported so far that includes fiber sensor multiplexing capability. Both simple systems are based on a wavelength swept laser to scan the reflection spectra of the FBGs, and they are composed by two identical-lengths optical paths: the first one intended to launch the amplified laser signal by means of Raman amplification and the other one is employed to guide the reflection signal to the reception system.
Open Access
Influence of saturable absorbers on fiber ring laser sensors
(SPIE, 2017) Rodríguez Cobo, Luis; Quintela, M. A.; Ruiz Lombera, Rubén; Pérez Herrera, Rosa Ana; López-Amo Sáinz, Manuel; López Higuera, José Miguel; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica
In this work, a fiber ring laser sensor has been employed to analyze the influence of passive Er-doped fiber acting as saturable absorber. Lasing modes of fiber ring lasers can be reduced by properly locating a saturable absorber that narrows the spectral width of the FBG that selects the lasing wavelength. Employing commercial Er-doped fiber, different configurations have been evaluated, reaching the SLM regime on a ring cavity of several meters. Thus, the achieved strain response of the whole sensor behaves at its mirror FBG, exhibiting linear response to strain.
Open Access
Láser random de fibra óptica asistido por reflectores de fibra con retrodispersión controlada artificialmente
(SEDOPTICA, 2021) Pérez Herrera, Rosa Ana; Roldán Varona, Pablo; Galarza Galarza, Marko; Sañudo-Lasagabaster Ibáñez, Silvia; 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; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA1928
Este trabajo presenta un láser de fibra tipo random (LFR) en cavidad semi-abierta, mediante amplificación híbrida Raman-Erbio y asistida por reflectores de fibra con retrodispersión controlada artificialmente (RFRCA). Como medio activo se ha empleado una combinación de 2,4 km de fibra compensadora de dispersión con dos tramos de fibra altamente dopada con erbio de 5 m cada uno. Se ha obtenido una única línea de emisión láser centrada a en 1553.8 nm y con una relación señal a ruido óptica de 47 dB cuando en la estructura se inyectaba una potencia de bombeo de 37.5 dBm. Además, se ha medido la estabilidad en términos de potencia de salida de este láser durante 3 horas, obteniendo una inestabilidad tan baja como 0,08 dB con un nivel de confianza del 100%.
Open Access
Hybrid Raman‑erbium random fiber laser with a half open cavity assisted by artificially controlled backscattering fiber refectors
(Springer Nature, 2021) Pérez Herrera, Rosa Ana; Roldán Varona, Pablo; Galarza Galarza, Marko; Sañudo-Lasagabaster Ibáñez, Silvia; 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; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA1928
A hybrid Raman-erbium random fber laser with a half-open cavity assisted by chirped artifcially controlled backscattering fber refectors is presented. A combination of a 2.4 km-long dispersion compensating fber with two highly erbium-doped fber pieces of 5 m length were used as gain media. A single random laser emission line centered at 1553.8 nm with an optical signal to noise ratio of 47 dB were obtained when pumped at 37.5 dBm. A full width at half maximum of 1 nm and a 100% confdence level output power instability as low as 0.08 dB were measured. The utilization of the new laser cavity as a temperature and strain sensor is also experimentally studied.
Open Access
Optical fiber networks for remote fiber optic sensors
(MDPI, 2012) Fernández Vallejo, Montserrat; López-Amo Sáinz, Manuel; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
This paper presents an overview of optical fiber sensor networks for remote sensing. Firstly, the state of the art of remote fiber sensor systems has been considered. We have summarized the great evolution of these systems in recent years; this progress confirms that fiber-optic remote sensing is a promising technology with a wide field of practical applications. Afterwards, the most representative remote fiber-optic sensor systems are briefly explained, discussing their schemes, challenges, pros and cons. Finally, a synopsis of the main factors to take into consideration in the design of a remote sensor system is gathered.