Person:
Iribas Pardo, Haritz

person.page.identifierURI

https://academica-e.unavarra.es/handle/2454/49294

Last Name

Iribas Pardo

First Name

Haritz

person.page.departamento

Estadística, Informática y Matemáticas

ORCID

0000-0003-4260-2379

person.page.upna

810714

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Now showing 1 - 10 of 31

Open Access
Eman dezagun paseo bat Iruñeko Buztintxurin eta Sanduzelain barna... baina ikus dezagun hiria matematiken begiradatik. Irakasleendako gida
(Ayuntamiento de Pamplona, 2022) Lasa Oyarbide, Aitzol; Abaurrea Larrayoz, Jaione; Iribas Pardo, Haritz; Wilhelmi, Miguel R.; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Iruñeko Buztintxuri eta Sanduzelai auzoetatik ibilbide matematiko bat diseinatu da. Lehen Hezkuntzako 6. mailako eta Bigarren Hezkuntzako 2. mailako ikasleek tokian bertan ebatzi beharreko arazo matematikoak dituzte, kokapen interesgarri jakin batzuei lotuta (lekuak, eraikinak edo eskulturak, hiri-altzarien elementuak...). Problema edo erronka matematikoak egokiak dira matematika irakasgaiaren ikaskuntza-estandar ofizialetarako, adierazitako mailetan. Informazioa edo pistak ematen dira, bai grafikoak, bai testualak, ebazteko.
Open Access
Simplified Brillouin sensor for structural health monitoring applications based on passive optical filtering
(SPIE, 2015) Iribas Pardo, Haritz; Urricelqui Polvorinos, Javier; Mariñelarena Ollacarizqueta, Jon; Sagüés García, Mikel; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We present a simplified configuration for distributed Brillouin optical time domain analysis sensors. The technique is based on passive optical filtering of the spectral components generated in an RF-pulse-modulated optical source. The aim of this configuration is to reduce the cost of the sensor by simplifying the generation of the optical waves involved in the sensing process. Proof-of-concept experiments demonstrate distributed temperature measurement with 1 m resolution over a 20 km sensing fiber.
Open Access
Compensation of nonlocal effects induced by the extinction ratio of pump pulses in Brillouin optical time-domain analysis sensors
(Optical Society of America, 2019) Mariñelarena Ollacarizqueta, Jon; Iribas Pardo, Haritz; Urricelqui Polvorinos, Javier; Loayssa Lara, Alayn; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We demonstrate a technique to compensate the nonlocal effects that appear in Brillouin optical time-domain analysis sensors when pump pulses with limited extinction ratio are deployed. These recently discovered nonlocal effects are originated in the interaction between the probe wave and the pulse pedestal. Hence, their compensation method is based on deploying a modulation (dithering) of the optical frequency of the probe and pulse pedestal waves that provides a reduction of the effective interaction length between them. This is implemented by taking advantage of the chirp associated to the direct current modulation of a semiconductor laser used as common source for both waves. The net effect of this procedure is that the probe and pulse pedestal waves display efficient Brillouin interaction just at correlation peaks along the fiber where the frequency difference between both waves remains constant. Proof-of-concept experiments in a 25-km sensing link demonstrate the performance of the technique, where large errors of more than 10 MHz in the measurement of the Brillouin frequency shift are completely compensated by introducing a sinusoidal dithering to the laser source.
Open Access
Eman dezagun paseo bat Iruñeko Arrotxapean barna... baina ikus dezagun hiria matematiken begiradatik. Jarduera-koadernoa
(Ayuntamiento de Pamplona, 2023) Iribas Pardo, Haritz; Abaurrea Larrayoz, Jaione; Wilhelmi, Miguel R.; Lasa Oyarbide, Aitzol; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Iruñeko Arrotxapea auzotik ibilbide matematiko bat diseinatu da. Lehen Hezkuntzako 6. mailako eta Bigarren Hezkuntzako 2. mailako ikasleek tokian bertan ebatzi beharreko arazo matematikoak dituzte, kokapen interesgarri jakin batzuei lotuta (lekuak, eraikinak edo eskulturak, hiri-altzarien elementuak…). Problema edo erronka matematikoak egokiak dira matematika irakasgaiaren ikaskuntza-estandar ofizialetarako, adierazitako mailetan. Informazioa edo pistak ematen dira, bai grafikoak, bai testualak, ebazteko.
Open Access
Contribution to the advancement of Brillouin optical time-domain analysis sensors
(2018) Iribas Pardo, Haritz; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Distributed fiber optic sensors (DFOS) are becoming an increasingly used technology to monitor the integrity of structures. This is due to the fact that this technology can be embedded within the structure and provide distributed information of several relevant parameters for the structure, such as stress, temperature or strain. In DFOS the fiber itself is the transducer, and the measurement of a given parameter is provided continuously along the fiber at a particular spatial resolution, without blind spots. This is the main advantage of DFOS compared to other sensing technologies, the fact that DFOS provide information of a given parameter over thousands or hundreds of thousands of positions along the optical fiber. Conversely, other sensing technologies only give information over the specific points where they are installed, that is to say, they are point sensors. This characteristic of distributed fiber sensors makes them enormously interesting when many points of a structure need to be monitored. In this case, a single distributed fiber sensor can replace many point sensors, which considerably reduces the cost per sensing point when monitoring large structures. In addition, due to the properties of the optical fiber, these sensors have a better performance compared to other kind of sensors. Among other important features, DFOS present a low signal loss, electromagnetic interference immunity, remote sensing and multiplexing capabilities, light weight, and are chemically passive, which make them a very attractive technology for field measurements. Therefore, DFOS have the added advantage of being electrically, magnetically, and chemically passive, so that can be placed in harsh environments, such as nuclear plants or areas with gas concentration, where, due to the possibility of a short circuit, electronic sensors cannot be placed. Al these characteristics make this technology unique. Among the different types of DFOS, those based on stimulated Brillouin scattering, and more specifically, those that build upon the Brillouin optical time-domain analysis (BOTDA) technique, are one of the most promising. The main characteristic that makes BOTDA sensors as promising, is the ability to perform distributed strain and temperature measurements over long distances at high spatial resolution. For the functioning of the sensor, the general interaction that takes place in the BOTDA technique involves two optical waves: a continuous wave probe and a counter-propagating pump pulse. The performance of the sensor response is limited, among others, by the maximum optical power of both waves that can be injected into the fiber. In this way, the main research line in BOTDA sensors is focused on the study of the physical limitations of the technique as well as the development of solutions to these constraints. Another important line relies on the simplification of the sensor setup so as to reduce the complexity and the cost of the sensor. This thesis dissertation contributes to the development of BOTDA sensors by means of different contributions in these two research lines. Several theoretical and experimental studies have been conducted to accurately determine the main limits to the sensor performance in terms of the maximum optical power of the pump and probe waves that can be used. One of the most important limitation in BOTDA sensors is the onset of non-local effects, which limits the maximum pump and probe waves power that can be injected in the fiber, and hence, the signal-to-noise ratio (SNR) at the receiver is worsen. The so-called non-local effects generate measurement errors, because the Brillouin spectra measured at distant locations depend on the interaction at previous positions in the fiber. In this research line, we have examined the effects caused by the limited extinction ratio (ER) of the pump pulse, finding that, among other impairments, it leads to the onset of a new non-local effect originated in the depletion of the pedestal of the pump wave. In addition, it has been found that the pedestal deformation caused by the transient response of erbium-doped fiber amplifiers, which are typically deployed to amplify the pump pulse, also constrains the performance of the sensor. Another contribution is the study of the techniques presented in the literature to mitigate the impairments caused by second-order non-local effects, which cause a frequency-dependent spectral deformation of the pulse. The findings of this study show that these techniques are only applicable when the Brillouin frequency shift (BFS) of the fiber is uniform, which is hard to find in real applications. Lastly, another subject of study is the limitations of the pump and probe optical power in coded-pump wave BOTDA configurations. We have observed that, in addition to some known limitations, there are two important restrictions that have to be taken into account: the onset of non-local effects and the non-linear amplification of the probe wave, both generated by the successive gain induced by the multiple pulses of the coded-pump wave. As a consequence of the findings of these studies, BOTDA configurations intended to solve these limitations have also been proposed during the thesis work. A technique to mitigate the constraints induced by the limited ER of the pump pulse has been presented. This method is based on adding a dithering to the optical source used to generate the two waves involved in the BOTDA sensor, so that the optical wavelength of both signals is modulated. In this way, the Brillouin interaction between the pedestal and the probe wavefronts become uncorrelated, and hence, the influence of the pedestal is greatly reduced. Another contribution is a technique focused on completely overcome the onset of second-order non-local effects. This method is based on continuously tracking the BFS distribution of the fiber, which combined with the probe-dithering method, has allowed, to the best of our knowledge, to inject the highest demonstrated probe wave power in a BOTDA sensor to date. In addition, in order to improve the SNR of the sensor, a novel BOTDA sensor has been proposed. This analyzer combines mono-color cyclic coding and probe-dithering techniques, so that the impairments caused by a coded pump wave are reduced, and hence, it is possible to increase the optical power and consequently enhance the sensing distance range. Finally, a novel simplified BOTDA sensor has been presented, which relies on passive optical filtering of the spectral components generated in a single optical source. In this way, the sensor setup is simplified reducing the number of optical devices, and therefore, the cost of the sensor is also reduced. This BOTDA configuration has been shown to have a performance comparable to more complex setups.
Open Access
Pulse coding linearization for Brillouin optical time-domain analysis sensors
(Optical Society of America, 2018) Mariñelarena Ollacarizqueta, Jon; Iribas Pardo, Haritz; Loayssa Lara, Alayn; Institute of Smart Cities - ISC
We introduce a simple method to extend the performance of pulse coding techniques in their application to Brillouin optical time-domain analysis sensors (BOTDA). It is based on applying a simple logarithmic processing on the detected probe wave that compensates the deviation from linearity of the sensor response for long code lengths. The technique ensures that the accumulated effect of a sequence of pulses is equal to the linear addition of the effects of the individual components, which is the essential condition to ensure a correct decoding of the probe gain measurement. We experimentally demonstrate the compensation of the Brillouin frequency shift error induced by the accumulated gain nonlinearity. Furthermore, a proof-of-concept 80 km sensing link within a total 200 km fiber loop demonstrated a better than 2 MHz precision with 2 m spatial resolution.
Open Access
Enhanced tolerance to pulse extinction ratio in Brillouin optical time domain analysis sensors by dithering of the optical source
(SPIE, 2015) Iribas Pardo, Haritz; Urricelqui Polvorinos, Javier; Sagüés García, Mikel; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We demonstrate the relaxation of the stringent requirements placed on the pulse extinction ratio in long-range Brillouin optical time-domain analysis sensors (BOTDA) by modulating the wavelength of the laser source that is used to generate both pump and probe waves. This modulation makes the counter-propagating pulse pedestal and probe waves to become correlated only at certain locations in the fiber, thus reducing the gain experienced by the probe wave, which is precisely the process that limits the performance in long-range BOTDAs. Proof-of-concept experimental results in a 20-km sensing link demonstrate a 6-dB reduction of the required modulator extinction ratio.
Open Access
Eman dezagun paseo bat Iruñeko Buztintxurin eta Sanduzelain barna... baina ikus dezagun hiria matematiken begiradatik. Jarduera-koadernoa
(Ayuntamiento de Pamplona, 2022) Lasa Oyarbide, Aitzol; Abaurrea Larrayoz, Jaione; Iribas Pardo, Haritz; Wilhelmi, Miguel R.; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Iruñeko Buztintxuri eta Sanduzelai auzoetatik ibilbide matematiko bat diseinatu da. Lehen Hezkuntzako 6. mailako eta Bigarren Hezkuntzako 2. mailako ikasleek tokian bertan ebatzi beharreko arazo matematikoak dituzte, kokapen interesgarri jakin batzuei lotuta (lekuak, eraikinak edo eskulturak, hiri-altzarien elementuak…). Problema edo erronka matematikoak egokiak dira matematika irakasgaiaren ikaskuntza-estandar ofizialetarako, adierazitako mailetan. Informazioa edo pistak ematen dira, bai grafikoak, bai testualak, ebazteko.
Open Access
Mathematical content on STEM activities
(Indonesian Mathematical Society, 2020) Lasa Oyarbide, Aitzol; Abaurrea Larrayoz, Jaione; Iribas Pardo, Haritz; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika; Gobierno de Navarra / Nafarroako Gobernua
In this paper, a number of STEM educational proposals are systematically analyzed from the lens of mathematics education. An extensive innovation project was implemented during the 2019/2020 academic year in a pilot study carried out in Schools and Teacher Training Programs in Navarre (Spain), comprising a bibliographical and source analysis as a previous step to characterize the existing material, and ultimately to design and test STEM projects at different educational levels from the point of view of mathematical education. All activities belong to international publications and widely used and contrasted web repositories, and seize the usual interval of compulsory education, i.e., from the beginning of Primary School (age 6/7) to the end of Secondary School (age 15/16). The findings draw a panorama of STEM activities where mathematics is mostly utilitarian, numbers and units are functionally used to measure quantities of magnitudes, and geometric contents serve the purpose of modeling a technological prototype. As it turns out, some STEM-labelled activities do not fulfill their principles and fundamental purposes. In lower levels, there is a common confusion between STEM activities and science laboratory projects; in higher levels, complex mathematical content could appear. Even though some activities are guided science laboratory projects, it is concluded that most STEM activities have the potential of a-didactical situations, i.e., contexts where students put into practice their personal problem-solving techniques before teachers formalize the mathematical content.
Open Access
Effects of pump pulse extinction ratio in Brillouin optical time-domain analysis sensors
(Optical Society of America, 2017) Iribas Pardo, Haritz; Mariñelarena Ollacarizqueta, Jon; Feng, Cheng; Urricelqui Polvorinos, Javier; Schneider, Thomas; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We report on two previously unknown non-local effects that have been found to impair Brillouin optical time-domain analysis (BOTDA) sensors that deploy limited extinction ratio (ER) pump pulses. The first one originates in the increased depletion of the pedestal of the pump pulses by the amplified probe wave, which in turn entails a reduced amplification of the probe and a measurement distortion. The second effect is due to the interplay between the transient response of the erbium-doped fiber amplifiers (EDFA) that are normally deployed to amplify the pump and the pedestal of the pump pulses. The EDFA amplification modifies the pedestal that follows the pulses in such a way that it also leads to a distortion of the measured gain spectra after normalization. Both effects are shown to lead to non-local effects in the measurements that have similar characteristics to those induced by pump pulse depletion. In fact, the total depletion factor for calculations of the Brillouin frequency shift (BFS) error in BOTDA sensors is shown to be the addition of the depletion factors linked to the pump pulse as well as the pedestal. A theoretical model is developed to analyze both effects by numerical simulation. Furthermore, the effects are investigated experimentally in long-range BOTDA sensors. The pedestal depletion effect is shown to severely constrain the probe power as well as the minimum ER of the pulses that can be deployed in BOTDA sensors. For instance, it is shown that, in a long-range dual-probe BOTDA, an ER higher that 32-dB, which is above that provided by standard electro-optic modulators (EOM), is necessary to be able to deploy a probe power of -3 dBm, which is the theoretical limit for that type of sensors. Even more severe can be the limitation due to the depletion effect induced by the EDFA transient response. It is found that the impairments brought by this effect are independent of the probe power, hence setting an ultimate limit for the BOTDA sensor performance. Experimentally, a long-range BOTDA deploying a 26-dB ER EOM and a conventional EDFA is shown to exhibit a BFS error higher than 1 MHz even for very small probe power.