Open Access
Random fiber lasers: application to fiber optic sensors networks
(IEEE, 2017) López-Amo Sáinz, Manuel; Leandro González, Daniel; Miguel Soto, Verónica de; Bravo Acha, Mikel; Fernández Vallejo, Montserrat; Pérez Herrera, Rosa Ana; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica
Recently, random mirrors have been proposed as a method to create fiber laser cavities. This kind of cavity is based on cooperative Rayleigh scattering, which is generated along a fiber due to the material inhomogeneities presented in that fiber. In this work, basics of Random fiber lasers and different demonstrated lasing sensors systems for interrogating arrays of optical fiber sensors are shown. These systems use different kinds of amplification and cavities schemes and can interrogate optical fiber sensors located up to 225 km away.
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
Random DFB fiber laser for remote (200 km) sensor monitoring using hybrid WDM/TDM
(IEEE, 2016) Leandro González, Daniel; Miguel Soto, Verónica de; Pérez Herrera, Rosa Ana; Bravo Acha, Mikel; López-Amo Sáinz, Manuel; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper, a random distributed feedback fiber laser is proposed as a multiplexing scheme for ultralong range measurements (up to 200 km). Optical fiber sensors are time and wavelength multiplexed overcoming one of the main limitations of long-range sensing setups, which is their limited multiplexing capability. The direct modulation of the laser's cavity allows the interrogation of sensors by measuring the reflected power for different wavelengths and distances. Fiber Bragg gratings placed at different fiber locations and wavelengths have been interrogated in two different sensor networks. In addition, in order to improve the performance of the system, some features have been analyzed.
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
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
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
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
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
Multiplexing optical fiber Fabry-Perot interferometers based on air-microcavities
(SPIE, 2019) Pérez Herrera, Rosa Ana; Novais, Susana; Bravo Acha, Mikel; Leandro González, Daniel; Silva, Susana; Frazão, Orlando; 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 demonstrate the multiplexing capability of new optical fiber Fabry-Perot interferometers based on airmicrocavities using a commercial FBG interrogator. Three optimized air-microcavity interferometer sensors have been multiplexed in a single network and have been monitored using the commercial FBGs interrogator in combination with FFT calculations. Results show a sensitivity of 2.18 π rad/mε and a crosstalk-free operation.
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.