Open Access
All fiber interferometer for ice detection
(Optica Publishing Group, 2018) Arozarena Arana, Jesús Antonio; Socorro Leránoz, Abián Bentor; Del Villar, Ignacio; Díaz Lucas, Silvia; Matías Maestro, Ignacio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC
This work presents an etched single-mode - multimode - single-mode structure that detects the solid-to-liquid change of state of the water due to an increased refractive index sensitivity within the 1.308 - 1.321 RIU range
Open Access
A comprehensive review of optical fiber refractometers: toward a standard comparative criterion
(Wiley, 2019) Urrutia Azcona, Aitor; Del Villar, Ignacio; Zubiate Orzanco, Pablo; Ruiz Zamarreño, Carlos; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
Thanks to the peculiarities of optical fiber and its ability to be combined with nanotechnology, precise and accurate measurements of the changes in optical properties (i.e., refractive index) of the medium surrounding the fiber are becoming possible with a high degree of performance. Thus, optical fiber sensors (OFSs) are increasingly finding applications in biochemistry and biomedicine. Here, all types of optical fiber refractometers are covered, and they are classified into three main groups: interferometers, grating-based structures, and resonance-based structures (the resonance is induced by coating the optical fiber sensor with a thin film). The performance of these different structures is compared by means of the most common parameters: sensitivity, full width at half minimum or maximum, figure of merit, and quality factor. The aim here is to provide a reliable and easy-to-use tool to compare the performance of the most recent developments on fiber optic refractometers.
Open Access
Monitoring of water freeze-thaw cycle by means of an etched single-mode - multimode - single-mode fiber-optic refractometer
(IEEE, 2023) Socorro Leránoz, Abián Bentor; Aginaga Etxamendi, Concepción Isabel; Díaz Lucas, Silvia; Urrutia Azcona, Aitor; Del Villar, Ignacio; Matías Maestro, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
As an alternative to the different technologies that permit the detection of in-situ ice formation on different surfaces, this contribution proposes the design of an etched single-mode – multimode – single-mode (E-SMS) fiber-optic-based structure as a multimode interference refractometer. This sensor provides enhanced properties with respect to a basic SMS structure, including a higher sensitivity and periodical interferometry bands that can measure surrounding refractive indices with repeatability and robustness. Since ice and water refractive indices are sufficiently different, this structure has been used to detect the freezing - thawing process of water taking place inside a freezer between -20°C and +20°C. Also, this work intends to show a proof of concept of a simple technology that can be applied in different situations, such as in smart cities, avionics, structural health monitoring or even to avoid a cold chain breakage. Inside, novel developments to better understand the working operation of the E-SMS structure are shown, together with a study on how to correlate optical and thermal measurements from a refractive index point of view.
Open Access
Low cutoff wavelength etched SMS structures towards verification of the quality of automotive antifreeze
(IEEE, 2020) Rodríguez Rodríguez, Wenceslao Eduardo; Rodríguez Rodríguez, Adolfo Josué; Ruiz Zamarreño, Carlos; Del Villar, Ignacio; Zúñiga Alanís, Manuel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Gobierno de Navarra / Nafarroako Gobernua, 2019 904 116; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA26
Optical fiber single mode-multimode-single mode (SMS) structures can be used as wavelength detection-based sensors. In this work, we focus on the performance at short wavelengths, where optical sources and detectors are less expensive. Here, a self-image band with a high transmission power is monitored in this short-wavelength range. In addition, the diameter and the length of the SMS structure have been optimized in order to improve the sensitivity of the device. In this sense, a maximum refractive index sensitivity of 305 nm/RIU was achieved by an etched SMS with a diameter of 34μ m. Furthermore, the obtained devices were used for testing the quality of automotive coolant and antifreeze liquid.
Open Access
Lossy mode resonance-based sensors in planar configuration: a review
(IEEE, 2023) Matías Maestro, Ignacio; Del Villar, Ignacio; Corres Sanz, Jesús María; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
Lossy mode resonance (LMR)-based sensors have attracted much interest during the last decade in the domain of optical fiber (OF). Here, it is shown that the progress made in the transfer of this technology to planar waveguides (PWs) with different sensing applications such as environmental sensors and biosensors. In addition, the inherent advantages in terms of robustness, simplicity, and easiness to generate novel complex structures are discussed.
Open Access
UV light detection with side polished CYTOP fiber
(IEEE, 2023) Ayechu Abendaño, Ada; Santano Rivero, Desiree; López Vargas, Juan David; Matías Maestro, Ignacio; Del Villar, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Cyclic transparent optical polymer (CYTOP) fiber, used mainly in strain detection and refractive index characterization of liquids, can be polished for the detection of ultraviolet (UV) light radiation. The study investigates the transmission spectra of CYTOP fiber exposed to different intensities of UV light, demonstrating a linear relationship. A simplified system using a single wavelength, i.e., 395 nm, shows real-time performance of the sensor in a range from 1 to 15 mW. The results reveal the potential of CYTOP fiber as a UV sensor with a sensitivity of 0.65%/mW and a limit of detection of 0.3 mW, offering implications for monitoring UV radiation exposure and related health risks. In addition, the effect of the UV light was also observed at longer wavelengths with a lower intensity variation, which suggests that CYTOP fiber could be used for transmitting the UV radiation detection in telecommunications bands.
Open Access
Generation of selective fringes with cascaded long-period gratings
(IEEE, 2006) Del Villar, Ignacio; Achaerandio Alvira, Miguel; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Gobierno de Navarra / Nafarroako Gobernua
The inscription of cascaded long-period gratings of different periods in optical fiber permits us to obtain both narrowband and wideband filters in the same spectrum. If used as an optical transducer, it may permit us to detect with the same device- wide and small parameter changes. The transmission spectra have been simulated using a theoretical model based on LP mode coupling and have been also experimentally demonstrated.
Open Access
D-shape optical fiber refractometer based on TM and TE lossy mode resonances
(SPIE, 2014) Zubiate Orzanco, Pablo; Ruiz Zamarreño, Carlos; Del Villar, Ignacio; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza
The fabrication and characterization of an optical fiber refractometer based on Lossy Mode Resonances (LMR) is presented. TiO2/ poly (sodium 4-styrenesulfonate) coatings deposited on side-polished D-shaped optical fibers are used as LMR supporting coatings. LMRs are sensitive to the external medium refractive index and D-shaped optical fibers enable the observation of TE and TM LMR polarizations. These refractometers based on TE and TM LMR showed an average sensitivity of 2737 nm/RIU and 2893 nm/RIU respectively for a surrounding medium refractive index (SMRI) range from 1.35 to 1.41.
Open Access
Multimode – coreless – multimode fiber-based sensors: theoretical and experimental study
(IEEE, 2019) San Fabián García, Noé; Socorro Leránoz, Abián Bentor; Del Villar, Ignacio; Díaz Lucas, Silvia; Matías Maestro, Ignacio; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
This paper presents a complete study on the spectral behavior of a multimode-coreless-multimode fiber-optic structure, as well as its application as a refractometer and a liquid level sensor. The combination of two standard multimode fibers fused to a coreless fiber segment allows generating narrow interferometric bands in the optical spectrum, whose sensitivity can be improved by an adequate selection of the dimensions of the device (the coreless segment length and the diameter of the sensing area). A second way to improve the performance of the device is to deposit a thin film of SnO2, which allows increasing the sensitivity up to 314 nm/RIU. This widens the number of applications where this structure can be used. As an example, a liquid level sensor with 0.73 nm/mm sensitivity is presented.
Open Access
Nanodeposition of materials with complex refractive index in long period fiber gratings
(IEEE, 2005) Del Villar, Ignacio; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Achaerandio Alvira, Miguel; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Gobierno de Navarra / Nafarroako Gobernua
An overlay of higher refractive index than the cladding is deposited on a Long Period Fiber Grating (LPFG). This permits to improve in a great manner the sensitivity of the device to ambient and overlay refractive index changes. This causes large shifts of the attenuation bands in the transmission spectrum. To obtain a maximum sensitivity for specific refractive indices of the overlay and the ambient, an optimum overlay thickness must be selected. If the refractive index of the overlay is complex there is an additional phenomenon of vanishing of the attenuation bands in the transmission spectrum. This occurs for specific thickness values of the overlay. The problem is analyzed with a numerical method based on LP mode approximation and coupled mode theory. Experimental results are contrasted with theoretical ones