Open Access
Single-longitudinal mode laser structure based on a very narrow filtering technique
(Optical Society of America, 2013) Rodríguez Cobo, Luis; Quintela, M. A.; Rota Rodrigo, Sergio; López-Amo Sáinz, Manuel; López Higuera, José Miguel; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
A narrow filtering technique based on the spectral overlapping of two uniform FBGs and applied to obtain a Single Longitudinal Mode (SLM) laser is proposed and demonstrated in this work. The two FBGs are spectrally detuned to reduce their coincident reflection response narrowing the equivalent filter bandwidth. A proof-of-concept linear laser has been built and tested exhibiting SLM operation even with temperature and strain variations.
Open Access
C and L band fiber lasers enhanced by ultrafast laser inscribed artificial backscatter reflectors
(Optica, 2022) Pérez Herrera, Rosa Ana; Roldán Varona, Pablo; Sánchez González, Arturo; Rodríguez Cobo, Luis; López Higuera, José Miguel; López-Amo Sáinz, Manuel; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This letter presents an experimental comparison between two linear-cavity erbiumdoped fiber lasers (EDFL) assisted by two different artificial backscatter fiber-based reflectors. Both reflectors were inscribed by femtosecond laser direct writing, one of them within a single-mode fiber (SMF) and the other one within a multi-mode fiber (MMF). Although the erbium-doped fiber amplifier (EDFA) used in both structures was the same and both reflectors were manufactured under the same parameters, the reflection spectrum of each was clearly different due to their different physical properties. The first linear-cavity EDFL, consisting of an SMF-based reflector with 9µm core and 125µm cladding, resulted in a single laser emission line located in the C-band and centered at 1564.4 nm, exhibiting an optical signal-to-noise ratio (OSNR) of 52dB when pumped at 100mW. On the other hand, a single laser emission line with a similar OSNR but in L-band (centered at 1574.5nm) was obtained when using an MMF-based reflector with 50µm core and 125µm cladding.
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
Micro-drilled optical fiber for enhanced laser strain sensors
(SPIE, 2019) 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
In this work, we present an experimental measurement of temperature and strain sensitivities of a micro-drilled optical fiber (MDOF). The MDOF consisted of a quasi-randomly distributed reflector along a single mode fiber (SMF). A fiber cavity laser based on MDOF was experimentally studied, attaining a single-wavelength laser emission centered at 1568.6nm. The output power level obtained from this single-laser oscillation when pumped at 140mW was around - 9.6dBm, and an optical signal to noise ratio (OSNR) of around 45dB was measured. Although temperature sensitivities of fiber Bragg gratings used as sensors are similar to our MDOF, strain sensitivity is enhanced around one order of magnitude when the MDOF was used.
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
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
Microdrilled tapers to enhance optical fiber lasers for sensing
(Nature Research, 2021) 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; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
In this work, an experimental analysis of the performance of different types of quasi-randomly distributed reflectors inscribed into a single-mode fiber as a sensing mirror is presented. These artificially-controlled backscattering fiber reflectors are used in short linear cavity fiber lasers. In particular, laser emission and sensor application features are analyzed when employing optical tapered fibers, micro-drilled optical fibers and 50 μm-waist or 100 μm-waist micro-drilled tapered fibers (MDTF). Single-wavelength laser with an output power level of about 8.2 dBm and an optical signal-to-noise ratio of 45 dB were measured when employing a 50 μm-waist micro-drilled tapered optical fiber. The achieved temperature sensitivities were similar to those of FBGs; however, the strain sensitivity improved more than one order of magnitude in comparison with FBG sensors, attaining slope sensitivities as good as 18.1 pm/με when using a 50 μm-waist MDTF as distributed reflector.
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
Stable L-band fiber laser sensor using a backscattering-based multimode fiber reflector
(Optica Publishing Group, 2022) Pérez Herrera, Rosa Ana; Roldán Varona, Pablo; Sánchez González, Arturo; Durán Lázaro, María; Rodríguez Cobo, Luis; López Higuera, José Miguel; López-Amo Sáinz, Manuel; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
A new and highly stable L-band fiber laser for sensing is demonstrated. An emission line at 1575.47 nm, was achieved using a special reflector. Good strain sensitivity, optical signal to noise ratio and output power stability were measured.
Open Access
Láseres de fibra óptica basados en reflectores clásicos, estrechados y microperforados
(SEDOPTICA, 2021) Sánchez González, Arturo; Pérez Herrera, Rosa Ana; Roldán Varona, Pablo; 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
En este trabajo se presenta un estudio comparativo entre distintos láseres de fibra óptica altamente dopada con erbio, con cavidades lineales conformadas tanto por reflectores puntuales clásicos como reflectores distribuidos. El estudio analiza experimentalmente las principales prestaciones de cada configuración, destacando las mejoras en estabilidad de emisión y estrechamiento de línea alcanzadas con fibras estrechadas microperforadas.