Open Access
Analysis of one-dimensional photonic band gap structures with a liquid crystal defect towards development of fiber-optic tunable wavelength filters
(Optical Society of America, 2003) Del Villar, Ignacio; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Claus, Richard O.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Gobierno de Navarra / Nafarroako Gobernua
A theoretical analysis of a fiber optical photonic band gap based tunable wavelength filter is presented. The design presented here is based on the quarter wave reflector with a liquid crystal defect layer in the middle of the structure. The filter generated by the structure is shifted in wavelength as the voltage applied to the structure is modified. Some critical parameters are analyzed: the effect of the consideration of fiber as the first layer and not the input medium in the shape of the filter, the number of layers of the structure, and the thickness of the defect layer. This last parameter determines the width of the wavelength sweep of the filter, but is limited by the creation of more defects. Some rules of practical implementation of this device are also given.
Open Access
Optical fiber sensors based on indium tin oxide surface plasmon resonance supporting coatings
(SPIE, 2009-10-05) Ruiz Zamarreño, Carlos; Hernáez Sáenz de Zaitigui, Miguel; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work, surface plasmon resonance (SPR) based optical fiber sensors are revisited by using a transparent conductive coating, Indium Tin Oxide in our case, as the SPR supporting layer. The utilization of these coatings shifts the plasmon resonance band to the infra-red region and allows the tunability of the SPR wavelength by adjusting the film fabrication parameters. Here, we study the fabrication process of these novel devices and characterize their response to variations in the refractive index of the external medium opening the door to a wide range of applications.
Open Access
Nanosensor for detection of glucose
(SPIE, 2004-06-09) Del Villar, Ignacio; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
A novel fibre-optic sensor sensitive to glucose has been designed based on electrostatic self-assembly method. The polycation of the structure is a mixture of poly(allylamine hydrochloride) (PAH) and Prussian Blue, whereas the polyanion is well-known enzyme glucose oxidase (GOx). The range of glucose concentration that can be measured is submilimolar and is located between 0.1 and 2 mM. Measures are based on a new detection scheme based on the slope of the change of signal produced by injection of glucose, yielding to a linear response. The sensor responses in a PH range between 4 and 7.4, which includes the physiological PH of blood. Some rules for estimation of the refractive index of the material deposited and the thickness of bilayers are also given.
Open Access
Sensitivity improvement of a humidity sensor based on silica nanospheres on a long-period fiber grating
(MDPI, 2009) Viegas, Diana; Goicoechea Fernández, Javier; Santos, José Luís; Araújo, Francisco Moita; Ferreira, Luis Alberto; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
This work addresses a new configuration that improves the sensitivity of a humidity sensor based on a long-period fiber grating coated with a SiO(2)-nanospheres film. An intermediate higher refractive index overlay, deposited through Electrostatic Self-Assembly, is placed between the fiber cladding and the humidity sensitive film in order to increase the total effective refractive index of the coating. With this intermediate design, a three-fold improvement in the sensitivity was obtained. Wavelength shifts up to 15 nm against 5 nm were achieved in a humidity range from 20% to 80%.
Open Access
An antibacterial surface coating composed of PAH/SiO2 nanostructurated films by layer by layer
(Wiley, 2010) Urrutia Azcona, Aitor; Rivero Fuente, Pedro J.; Ruete Ibarrola, Leyre; Goicoechea Fernández, Javier; Fernández Valdivielso, Carlos; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería; Ingeniaritza; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Institute of Smart Cities - ISC
In this work we propose a novel antibacterial coating composed of SiO2 and the polymer Poly(allylamine hydrochloride) (PAH). The coating was fabricated by the technique Layer-by-Layer (LbL). This technique has already been used in previous works, and it has the advantage that it allows to control the construction of nanosized and well organized multilayer films. Here, the new nanotexturized LbL SiO2 surface acts as antibacterial agent. The fabricated coatings have been tested in bacterial cultures of genus Lactobacillus to observe their antibacterial properties. It has been demonstrated these PAH/SiO2 coating films have a very good antimicrobial behaviour against this type of bacteria.
Open Access
Photonic crystal fiber temperature sensor based on quantum dot nanocoatings
(Hindawi / Wiley, 2009) Larrión Zabaleta, Beatriz; Hernáez Sáenz de Zaitigui, Miguel; Arregui San Martín, Francisco Javier; Goicoechea Fernández, Javier; Bravo Larrea, Javier; Matías Maestro, Ignacio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Quantum dot nanocoatings have been deposited by means of the Layer-by-Layer technique on the inner holes of Photonic Crystal Fibers (PCFs) for the fabrication of temperature sensors. The optical properties of these sensors including absorbance, intensity emission, wavelength of the emission band, and the full width at half maximum (FWHM) have been experimentally studied for a temperature range from -40 to 70ºC.
Open Access
High sensitive refractometers based on lossy mode resonances (LMRs) supported by ITO coated D-shaped optical fibers
(Optical Society of America, 2015) Zubiate Orzanco, Pablo; Ruiz Zamarreño, Carlos; Del Villar, Ignacio; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Tin doped indium oxide (ITO) coatings fabricated onto D-shaped optical fibers are presented as the supporting medium for Lossy Mode Resonances (LMRs) generation. The characteristic geometry of ITO-coated D-shaped optical fibers enables to observe experimentally LMRs obtained with both TM and TE polarized light (LMRTM and LMRTE). This permits to obtain a maximum transmission decay of 36 dB with a LMR spectral width of 6.9 nm, improving that obtained in previous works, where the LMRs were a combination of an LMRTM and an LMRTE. Surrounding medium refractive index (SMRI) sensitivity characterization of LMRTM has been performed obtaining a maximum sensitivity of 8742 nm/RIU in the range 1.365-1.38 refractive index units (RIU) which overcomes that of surface plasmon resonance-based optical fiber devices presented in recent works.
Open Access
A comparative study between SMS interferometers and lossy mode resonace optical fiber devices for sensing applications
(SPIE, 2015) Socorro Leránoz, Abián Bentor; Hernáez Sáenz de Zaitigui, Miguel; Del Villar, Ignacio; Corres Sanz, Jesús María; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Optical fiber sensors are of great interest due to their intrinsic advantages over electronic sensors. In this work, the sensing characteristics of two different and novel optical fiber devices are compared, after simultaneously depositing a thin-film using the layer-by-layer assembly deposition process. The first one is an SMS structure, formed by splicing two single-mode fiber pigtails on both sides of a coreless multimode fiber segment. This structure induces an interferometric phenomenon that generates several attenuation and transmission bands along the spectrum. These bands are sensitive to variations in the surrounding refractive index, although this sensitivity has been enhanced by a TiO2/PSS thin-film. The other device is a 40 mm uncladded segment of a 200 µm-core multimode optical fiber. When coated by a TiO2/PSS thinfilm, part of the light transmitted into the uncladded core is coupled into the thin-film, generating a lossy mode resonance (LMR). The absorption peaks due to these phenomena red-shift as long as the thin-film thickness increases or the external RI becomes higher. The performance of these devices as refractometers and relative humidity sensors are tested. Results show that the LMR-based sensor is more sensitive in both situations, in spite of its lower sensitivity. Particularly, it presents a 7-fold sensitivity enhancement when measuring surrounding medium refractive index changes and a 10-fold sensitivity enhancement when measuring environmental relative humidity. To our knowledge, this is the first time that a comparative study between SMS and LMR sensors is performed.
Open Access
Humidity sensor based on Bragg gratings developed on the end facet of an optical fiber by sputtering of one single material
(MDPI, 2017) Ascorbe Muruzabal, Joaquín; Corres Sanz, Jesús María; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The refractive index of sputtered indium oxide nanocoatings has been altered just by changing the sputtering parameters, such as pressure. These induced changes have been exploited for the generation of a grating on the end facet of an optical fiber towards the development of wavelength-modulated optical fiber humidity sensors. A theoretical analysis has also been performed in order to study the different parameters involved in the fabrication of this optical structure and how they would affect the sensitivity of these devices. Experimental and theoretical results are in good agreement. A sensitivity of 150 pm/%RH was obtained for relative humidity changes from 20% to 60%. This kind of humidity sensors shows a maximum hysteresis of 1.3% relative humidity.
Open Access
Optical fiber refractometers based on indium tin oxide coatings with response in the visible spectral region
(Elsevier, 2011) Ruiz Zamarreño, Carlos; López, S.; Hernáez Sáenz de Zaitigui, Miguel; Del Villar, Ignacio; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Gobierno de Navarra / Nafarroako Gobernua
This work presents the fabrication of optical fiber refractometers based on indium tin oxide (ITO) coatings with response in the visible spectral region. ITO thin-films have been sputtered by employing a rotating mechanism that enables the fabrication of smooth homogeneous coatings onto the optical fiber core. The ITO coated optical fiber devices present several resonances in the visible and infra-red region. These resonances show high optical power attenuations (more than 10 dB) in the visible spectral region, which produces changes in the colour of the output visible light. Therefore, since these resonances shift as a function of the surrounding medium refractive index (SMRI), it is feasible to determine the refractive index of the outer medium in contact with the ITO coating by simply monitoring the chromatic coordinates of the visible output light.