Open Access
Second-order nonlocal effects mitigation in Brillouin optical time-domain analysis sensors by tracking the Brillouin frequency shift profile of the fiber
(IEEE, 2017) Mompó Roselló, Juan José; Iribas Pardo, Haritz; Urricelqui Polvorinos, Javier; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Gobierno de Navarra / Nafarroako Gobernua
We report on an additional limitation that has been found in Brillouin optical time-domain analysis (BOTDA) sensors due to the so-called second-order nonlocal effects (NLE). Second-order NLE appear in BOTDA setups that deploy a double probe waves to compensate the transfer of energy between the pump pulse and the probe wave, and are related to a spectral distortion of the pump pulse that leads to measurement errors and an effective limit on the maximum probe power that can be deployed in the sensor. We theoretically and experimentally demonstrate that the techniques that have been presented so far in the literature to compensate second-order NLE are only effective in the case that the Brillouin frequency shift (BFS) along the sensing fiber is uniform. However, this requirement for uniformity is not realistic in real world scenarios in which a variety of fibers with different BFS and subjected to different environmental conditions are typically deployed. Therefore, we demonstrate a new method to mitigate the effects of BFS variation in the BOTDA setups that compensate second-order NLE. This method is based on introducing an additional wavelength modulation to the probe wave so as to track the mean BFS changes along the sensing fiber link. With this method, we demonstrate a BOTDA setup that, without coding, distributed amplification, or any other form of performance enhancement, achieves a sensing length of 120 km with 3-m spatial resolution and 2-MHz measurement precision. Moreover, the setup demonstrates, to our knowledge, the largest probe power ever injected in a BOTDA sensing link.
Open Access
Phasorial differential pulse-width pair technique for long-range Brillouin optical time-domain analysis sensors
(Optical Society of America, 2014) 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 introduce a novel phasorial differential pulse width pair (PDPP) method for Brillouin optical time domain analysis (BOTDA) sensors that combines spatial resolution enhancement with increased tolerance to non local effects. It is based on the subtraction of the complex time domain traces supplied by a sensor configuration that uses a phase modulated probe wave and RF demodulation. The fundamentals of the technique are first described theoretically and using numerical simulation of the propagating waves. Then, proof of concept experiments demonstrate the measurement of the Brillouin frequency shift distribution over 50 km. The system is shown to withstand large variations of the pump power generated by its interaction with a powerful probe wave along the fiber; hence, highlighting the potential of the PDPP technique to increase the detected signal to noise ratio in long range BOTDA. Moreover, the PDPP is also shown to increase the measurement contrast by allowing the use of relatively long duration pulses while retaining 1 m spatial resolution.
Open Access
Dynamic BOTDA measurements using Brillouin phase-shift
(SPIE, 2012) Urricelqui Polvorinos, Javier; Zornoza Indart, Ander; Sagüés García, Mikel; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We demonstrate a novel dynamic BOTDA sensor based, for the first time to our knowledge, on the use of the Brillouin phase-shift instead of the conventional Brillouin gain. This provides the advantage of measurements that are largely immune to variations in fiber attenuation or changes in pump pulse power. Furthermore, the optical detection deployed can lead to an enhanced precision or measurement time and to the broadening of the measurement range. Proof of concept experiments demonstrate 1.66 kHz measurement rate with 1 m resolution over a 160 m sensing fiber length.
Open Access
Development and implementation of standardized interfaces for an Android based telemonitoring server
(2011) Urricelqui Polvorinos, Javier; Serrano Arriezu, Luis Javier; Gerbovics, Ferenc; Escuela Técnica Superior de Ingenieros Industriales y de Telecomunicación; Telekomunikazio eta Industria Ingeniarien Goi Mailako Eskola Teknikoa; University of Applied Sciences Technikum Wien (Austria); Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
El tema de este proyecto fin de carrera es el desarrollo e implementación de interfaces estandarizadas para un servidor de telemonitorización basado en Android complementario al dispositivo HDH. El sistema de telemonitorización conocido como Health Data Hub (HDH) ha sido desarrollado por un grupo de estudiantes de Máster en la University of Applied Sciences Technikum Wien, obteniendo como resultado un dispositivo tipo muñequera capaz de medir datos médicos mediante sensores, recibir datos de parámetros vitales por parte de dispositivos para el cuidado de la salud, además del reenvío de datos como mensajes de alarma y diversas actualizaciones a distintos servidores mediante interfaces estandarizadas. Por lo que el principal objetivo de este proyecto es el desarrollo e implementación de interfaces estandarizadas para un servidor de telemonitorización basado en Android, capaz de gestionar los datos enviados por los dispositivos enmarcados en este proyecto según el estándar HL7 v2.6. El dispositivo HDH es capaz de medir parámetros vitales, generar actualizaciones automáticas y mensajes de alarma para enviarlos posteriormente al Android server mientras el paciente realiza su vida cotidiana. De esta manera, el usuario del Android server puede disponer de información relativa al usuario del HDH. El conjunto de dispositivos que se encuentran en el marco del proyecto HDH son el servidor HDH, el cliente HDH, el servidor Android y el dispositivo HDH. El servidor Android desarrollado durante este proyecto, consiste en una solución esencial de este entorno. El Android server está realizado sobre la plataforma Android, lo cual permite ofrecer nuevas funcionalidades y servicios que dotan de gran potencial al proyecto permitiendo llevar a cabo los objetivos propuestos. Además, Android se define como código abierto, lo cual permite al desarrollador una fácil integración a otros entornos y provee herramientas que permiten que el desarrollo de la aplicación sea más atractivo para el programador. Este proyecto ha sido desarrollado en colaboración con Amagoia Tellechea, estudiante de la Universidad Pública de Navarra y estudiante de intercambio Erasmus en la University of Applied Sciences Technikum Wien. Las tareas asignadas para el desarrollo de la aplicación Android server fueron proporcionadas a ambos estudiantes, por lo que se trabajó conjuntamente en el desarrollo de la aplicación desde sus inicios hasta las últimas soluciones adoptadas para su desarrollo.
Open Access
Phasorial DPP-BOTDA sensor tolerant to non-local effects
(SPIE, 2014) 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 introduce a modification of the differential pulse width pair technique in a BOTDA sensor based on a phase modulated probe wave and RF demodulation. This provides a differential Brillouin phasorial signal with high spatial and spectral resolution in both components (magnitude and phase shift). Moreover, the use of a phase modulated probe wave provides RF phase shift measurements tolerant to the emergence of non local effects. The combination of both techniques can lead to the development of long range BOTDA sensors. Proof of concept experiments demonstrate RF phase shift measurements with 1m spatial resolution over 50km and an uncertainty of 1.3ºC at the worst contrast position.
Open Access
Polarization diversity for Brillouin distributed fiber sensors based on a double orthogonal pump
(SPIE, 2014) Urricelqui Polvorinos, Javier; López Fernandino, Felipe; Sagüés García, Mikel; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We demonstrate a novel Brillouin optical time domain analysis sensor deploying a polarization diversity technique which eliminates the need for polarization scrambling, providing measurements that are largely immune to the state of polarization of the probe wave and the pump pulses throughout the sensing fiber. This can be exploited to reduce the measurement time or can lead to an enhanced precision. Proof of concept experiments demonstrate a 651 Hz sampling rate with 1m resolution over a 930m sensing fiber.
Open Access
Brilloun optical time domain analysis sensor assisted by a Brillouin distributed amplifier
(SPIE, 2015) 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 extension of the measurement range of Brillouin optical time-domain analysis (BOTDA) sensors using a distributed Brillouin amplifier (DBA). The technique is based on injecting a DBA pump wave in the fiber to generate an additional Brillouin interaction that amplifies the BOTDA pump pulses. Furthermore, the differential pulse-width pair method is used to counteract the detrimental effects of the DBA amplification on the temporal shape of the pulses. Experimental proof-of-concept results in a 50-km fiber link demonstrate full compensation of the fiber’s attenuation with no penalty on the signal-to-noise ratio of the detected probe wave.
Open Access
Overcoming non-local effects and Brillouin threshold limitations in Brillouin distributed sensors
(SPIE, 2015) Urricelqui Polvorinos, Javier; Ruiz Lombera, Rubén; Sagüés García, Mikel; Mirapeix, Jesús; López Higuera, José Miguel; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
We demonstrate, for the first time to our knowledge, a Brillouin optical time domain analysis sensor that is able to operate with a probe power larger than the Brillouin threshold of the deployed sensing fiber and that is free from detrimental non-local effects. The technique is based on a dual-probe-sideband setup in which a frequency modulation of the probes waves along the fiber is introduced. This makes the frequency of maximum interaction between pump and probes to vary along the fiber, thus mitigating the pump pulse depletion and making it possible to use very large probe power, which brings an improved signal-to-noise ratio in detection.
Open Access
Structural health monitoring of solar trackers using distributed fiber optic sensors
(SPIE, 2019) Mariñelarena Ollacarizqueta, Jon; Mompó Roselló, Juan José; Zurita Gabasa, Jesús; Urricelqui Polvorinos, Javier; Júdez Colorado, Aitor; López-Amo Sáinz, Manuel; Jiménez Romero, Sergio; Achaerandio, Álvaro; Loayssa Lara, Alayn; Institute of Smart Cities - ISC; Gobierno de Navarra / Nafarroako Gobernua, 0011-1365-2017-000122; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We demonstrate the application of a novel type of distributed fiber optic sensors (DFOSs) to dynamically monitor the effects of wind on solar tracker structures used in photovoltaic power stations. This DFOS is based on the stimulated Brillouin scattering nonlinear optical effect in optical fiber, which can be used to measure the distribution of strain and temperature along a given structure. However, contrary to existing solutions, the sensor provides dynamic real-time measurements with hundreds or even thousands of full simultaneous measurements for all positions in the fiber each second. Moreover, high-precision and high spatial resolution are obtained. This so-called dynamic Brillouin optical time-domain analysis (D-BOTDA) sensor provides real-time monitoring of the bending and torsion of the structure of solar trackers in response to wind load. This helps the solar tracker manufacturer asses and improve the mechanical designs so as to introduce corrective measures and develop cost-effective components that properly withstand the effects of wind at any given location. We experimentally demonstrate the application of a D-BOTDA sensing system to measure distributed bending and, for the first time to our knowledge, also distributed torsion along the stressed beam of the solar tracker. For this purpose, we have developed a procedure to instrument the torsion beam with two optical sensing fibers that are fixed helically wound along the beam in opposite directions, so that any common-mode thermal or bending effects are removed. We initially performed tests in a laboratory facility in which sections of the torsion beam could be subjected to controlled moments. Static and dynamic loads were applied and the measured deformations were compared to those obtained with fiber Bragg gratings, which just provide point measurements of strain. In both cases, full agreement was demonstrated. Finally, the system was installed in an operational solar park.
Open Access
Overcoming non-local effects and Brillouin threshold limitations in Brillouin optical time domain sensors
(IEEE, 2015) Ruiz Lombera, Rubén; Urricelqui Polvorinos, Javier; Sagüés García, Mikel; Mirapeix, Jesús; López Higuera, José Miguel; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We demonstrate, for the first time to our knowledge, a Brillouin optical time domain analysis (BOTDA) sensor that is able to operate with a probe power larger than the Brillouin threshold of the deployed sensing fiber and that is free from detrimental non-local effects. The technique is based on a dual-probe-sideband setup in which an optical frequency modulation of the probe waves along the fiber is introduced. This makes the optical frequency of the Brillouin interactions induced by each probe wave on the pump to vary along the fiber so that two broadband Brillouin gain and loss spectra that perfectly compensate are created. As a consequence, the pulse spectral components remain undistorted avoiding non-local effects. Therefore, a very large probe power can be injected, which improves the signal-to-noise ratio in detection for long-range BOTDA. Moreover, the probe power can even exceed the Brillouin threshold limit due to their frequency modulation, which reduces the effective amplification of spontaneous Brillouin scattering in the fiber. Experiments demonstrate the technique in a 50-km sensing link in which 8 dBm of probe power is injected.