Open Access
Femtosecond laser inscription of diffraction gratings in CYTOP fibers for optical fiber sensing
(SEDOPTICA, 2021) Lomer, Mauro; Roldán Varona, Pablo; Algorri, J. F.; Rodríguez Cobo, Luis; Pérez Herrera, Rosa Ana; 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; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The use of the new CYTOP fibers for the inscription of optical structures and the sensing of different parameters has started to gain importance in the last decade. This work presents the design and manufacture of a CYTOP fiber-based optical structure intended for later use as a refractive index sensor. The structure is based on a diffraction grating inscribed in an area of the fiber with a specific curvature, and previously polished.
Open Access
Single longitudinal mode lasers by using artificially controlled backscattering erbium doped fibers
(IEEE, 2021) 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
In this work, we propose and experimentally demonstrate a new distributed short linear cavity fiber laser. At one of the cavity ends, fabricated by a commercial femtosecond fiber laser chirped pulse amplfier, an artificially controlled backscattering erbium doped fiber section has been connected. This distributed reflector acts also as a saturable absorber, leading to the generation of tunable and switchable single longitudinal-mode laser emissions. The distributed reflector consists of 9 micro-drilled sections of about 1cm each one and randomly spread throughout 2 meters of highly doped erbium fiber. The total length of the fiber laser is 9.5 m and the laser shows a single mode behavior at all the emitted wavelengths. Using this new kind of reflecting saturable absorber, single and multiple single-mode emissions can be obtained. The achieved laser presents a pump threshold as low as 45 mW and shows up to 8 different single-mode emission lines with an optical signal to noise ratio of 45dB.
Open Access
Analyzing implicit gender bias in Optics and Photonics at the predoctoral stage in Spain
(Sociedad Española de Óptica, 2023) Tomás, María-Baralida; Heras, Alba de las; Santamaría Fernández, Beatriz; Gómez Varela, Ana Isabel; Benedi García, Clara; Delgado Pinar, Martina; González Fernández, Verónica; Pérez Herrera, Rosa Ana; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza
Los prejuicios de género desempeñan un papel muy importante en áreas relacionadas con la ciencia, la tecnología, la ingeniería y las matemáticas (STEM). La asociación del género con determinados atributos, comportamientos o profesiones conduce a una menor proporción de mujeres en STEM. En el campo de la Óptica y la Fotónica, podemos identificar una disparidad de género entre enfoques técnicos o bioclínicos dentro de la misma área al examinar la autoría de la tesis defendida. En este trabajo, cuantificamos el impacto del sesgo implícito de género en los programas de doctorado relacionados con la Óptica y Fotónica en España. Aquí presentamos un estudio exhaustivo sobre los descriptores UNESCO de las tesis defendidas en el periodo 2015-2020 a través del repositorio de acceso abierto TESEO, donde se recopilan todas las tesis doctorales de las universidades españolas. Se considera el programa de doctorado de cada tesis y se clasifica en una categoría técnica o bioclínica. Con esta clasificación, cuantificamos el número de autores y autoras dentro de cada categoría, y los resultados muestran un claro desequilibrio en la mayoría de los descriptores evaluados: los hombres son más propensos a elegir programas de doctorado técnicos, mientras que las mujeres están mayoritariamente presentes en programas clínicos o biológicos. Esta diferencia se observa incluso en los descriptores en los que ambos sexos están representados por igual. Por un lado, la infrarrepresentación femenina es mayor en "Física", "Astronomía y Astrofísica", "Ciencias de la Tierra y del Espacio" y "Ciencias Tecnológicas". Por el contrario, las áreas de "Química", "Ciencias de la Vida" y "Ciencias Médicas" muestran una distribución más equilibrada entre hombres y mujeres en la mayoría de los descriptores.
Open Access
Optical fiber lasers assisted by microdrilled optical fiber tapers
(Optical Society of America, 2019) Pérez Herrera, Rosa Ana; Pallarés Aldeiturriaga, D.; Júdez Colorado, Aitor; Rodríguez Cobo, Luis; 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
In this Letter, we present an analysis of the backscattering generated in a microdrilled tapered fiber within a short-linear-cavity fiber laser. We propose and experimentally demonstrate a fiber cavity laser based on a tapered optical fiber segment that generates artificially controlled backscattering. The 50-mu m-waist taper was fabricated from a standard single-mode fiber, and the taper was subsequently microdrilled using a femtosecond laser micromachining system. The laser generation properties conferred by the microdrilled optical fiber taper were experimentally investigated. A single-wavelength laser emission at 1562 nm with an output power of 10 dBm and an optical signal-to-noise ratio greater than 45 dB is demonstrated.
Open Access
Wavelength-switchable L-band fiber laser assisted by random reflectors
(EDP Open, 2023) 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
A wavelength-switchable L-band erbium-doped fiber laser (EDFL) assisted by an artificially controlled backscattering (ACB) fiber reflector is here presented. This random reflector was inscribed by femtosecond (fs) laser direct writing on the axial axis of a multimode fiber with 50 lm core and 125 lm cladding with a length of 17 mm. This microstructure was placed inside a surgical syringe to be positioned in the center of a high-precision rotation mount to accurately control its angle of rotation. Only by rotating this mount, three different output spectra were obtained: a single wavelength lasing centered at 1574.75 nm, a dual wavelength lasing centered at 1574.75 nm and 1575.75 nm, and a single wavelength lasing centered at 1575.5 nm. All of them showed an optical signal-to-noise ratio (OSNR) of around 60 dB when pumped at 300 mW
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
Multiparameter sensor based on a multiinterferometric serial configuration for temperature and strain measurements
(IEEE, 2021) Pérez Herrera, Rosa Ana; Bravo Acha, Mikel; Leandro González, Daniel; Novais, Susana; Pradas Martínez, Javier; 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, a multi-parameter point sensor based on the combination of Fabry-Perot (FP) and the anti-resonant (AR) reflecting guidance in cascade configuration is proposed and experimentally demonstrated. This structure, based on FP interference and AR reflecting guidance, was fabricated with two different air micro-cavities. The attained experimental results showed different strain and temperature sensitivities for the antiresonance contribution. However, when analyzing the FP interference, only strain sensitivity was observed, demonstrating that this air micro-cavity was also insensitive to temperature variations.
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
Multicore fiber sensors for strain measurement towards traffic monitoring
(SPIE, 2023) Sánchez González, Arturo; Pradas Martínez, Javier; Corera Orzanco, Íñigo; Bravo Acha, Mikel; Leandro González, Daniel; Dauliat, Romain; Jamier, Raphael; Roy, Philippe; Pérez Herrera, Rosa Ana; López-Amo Sáinz, Manuel; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA06-2022
In this work, two new interferometric sensors based on multicore optical fibers for the measurement of strain with the ultimate goal of traffic monitoring are presented. The operating principle of each sensor relied on the monitoring of the phase shift difference accumulated between the supermodes of the structure of the multicore segment in a full round trip. The strain characterization for both sensors resulted in a linear response, with sensitivities of -4.073·10-3 rad/με and - 4.389·10-3 rad/με for the aligned and V-shaped cases respectively, and one-hour instabilities below 4.6·10-3 rad with a 95% confidence level. These results suggest its feasibility in applications requiring high sensitivities over very wide strain ranges, such as heavy-vehicle traffic monitoring. To corroborate the hypothesis, both sensors were integrated into the pavement and their response to the traffic was analyzed.
Open Access
High sensitivity fiber-optic liquid level sensor using biconical tapered fibers
(Optical Society of America, 2018) Júdez Colorado, Aitor; Leandro González, Daniel; Pérez Herrera, Rosa Ana; Galarza Galarza, Marko; 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
A liquid level sensor is presented using a biconical tapered standard single-mode fiber, being its main characteristic an outstanding sensitivity for a low cost transducer. Temperature compensation is enabled with the same interrogation equipment.