Open Access
Torsion sensor using a high-birefringence nine-hole optical fiber
(IEEE, 2025-07-03) Rodríguez Rodríguez, Armando; Vento Álvarez, José Raúl; Galarza Galarza, Marko; Vanegas Tenezaca, Evelyn Dayanara; Schuster, Kay; Bravo Acha, Mikel; López-Amo Sáinz, Manuel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
This article presents a novel high-birefringence fiber-based torsion sensor based on a microstructured optical fiber with nine holes and seven cores microstructured holes and cores optical fiber (MHCF) embedded into a Sagnac interferometer (SI). A segment of this fiber is inserted into a symmetric SMF-MMF-MHCF-MMF-SMF arrangement, which provides efficient coupling to the multiple cores of the birefringent fiber and, consequently, multimode interference (MMI). Fast Fourier transform (FFT) spectral data analysis is employed to enhance measurement stability and reduce dependence on optical source variations. The sensor demonstrates a linear response to torsion angles between −50◦ and +50◦ , with a 16-mrad/◦ sensitivity. The high sensitivity and good linearity of the sensor are enhanced through the application of machine learning (ML) techniques.
Open Access
Improved liquid level sensor by using a multi-capillary structure
(Optica Publishing Group, 2023) Vanegas Tenezaca, Evelyn Dayanara; López-Amo Ocón, Manuel; Dauliat, Romain; Jamier, Raphael; Roy, Philippe; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
We demonstrate a new optical fiber liquid level sensor based on two sections of capillary optical fibers spliced between single-mode fibers. Last section without coating is in contact with the liquid. A measurement range of 60 mm is obtained when the structure is monitored in reflection by using a FBGs interrogator.
Open Access
Multidirectional bending sensor using capillary fibers and machine learning for real-time applications
(IEEE, 2025-02-25) Vanegas Tenezaca, Evelyn Dayanara; Galarza Galarza, Marko; Dauliat, Romain; Jamier, Raphael; Roy, Philippe; López-Amo Sáinz, Manuel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Publica de Navarra / Nafarroako Unibertsitate Publikoa
In this article, the design and implementation of a bidirectional curvature sensor based on a fiber-optic interferometer are presented. The sensor structure was fabricated by fusing a capillary fiber fragment between single-mode fibers (SMFs), with the addition of a long end capillary to promote a long interferometric section, forming a Fabry-Perot (FP) cavity. Detailed analysis of the curvature data was carried out using machine learning techniques, allowing accurate classification of curvature in both directions of rotation. The experimental results showed excellent agreement (R2: 0.9998) with the predicted values. The sensor exhibits a maximum error of 1.9485°. This approach presents significant potential for applications requiring accurate real-time curvature measurements.
Open Access
High resolution liquid level measurement using a multisection interferometer based on capillary fibers
(IEEE, 2024-08-05) Vanegas Tenezaca, Evelyn Dayanara; Galarza Galarza, Marko; Dauliat, Romain; Jamier, Raphael; Roy, Philippe; López-Amo Sáinz, Manuel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
This paper presents a novel capillary structure for liquid level measurement. The multifiber interferometric structure, which employs two capillary sections, is well-suited to the measurement of liquid levels in both short distances and with high resolution. The measurement range extends up to 60 mm with a resolution of 0.70 mm.
Open Access
Power over fiber system for heterogeneous sensors multiplexing
(IEEE, 2024-06-12) Rodríguez Rodríguez, Armando; Vanegas Tenezaca, Evelyn Dayanara; Vento Álvarez, José Raúl; López-Amo Sáinz, Manuel; Bravo Acha, Mikel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Uniertsitate Publikoa
This paper presents a Power-over-Fiber based remote electronic and optical fiber sensors multiplexing scheme. The system architecture consists of a 50-km linear cavity Raman-fiber laser that is used for interrogation of FBG optical fiber sensors. Simultaneously, electronic sensors information is modulated in amplitude while the optical sensors' data are encoded in the spectral information. In order to bias the electronic sensors, the residual power of the Raman pump laser is collected in an energy harvesting unit. This electric power is used for biasing an ATTiny85 control unit and two electro-optical modulators. A proof-of-concept is presented where a couple of optical fiber-Bragg-gratings sensors collect strain information that is self-compensated in temperature according to the digital data achieved from the electronic sensors. A 9.6 kbit/s data rate was achieved using Mach-Zehnder amplitude modulators and a maximum 35 ksample/s was retrieved using a high-speed C-band spectrometer and performing spectral analysis via a software developed in Python. Authors
Open Access
Capillary-based optical fiber sensor for turbidity measurement
(SPIE, 2025-05-22) Vanegas Tenezaca, Evelyn Dayanara; Galarza Galarza, Marko; Dauliat, Romain; Jamier, Raphael; Roy, Philippe; Cobo, Adolfo; López-Amo Sáinz, Manuel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
This work introduces an innovative capillary or hollow core-based sensor designed to measure turbidity by using the reflection of light in its cladding. The structure consists of two different capillary sections and has been optimized to maximise the interaction of light with the external liquid. Experimentation includes data collection from different turbidity levels using the reflected spectrum. To improve the measuring results, machine learning is implemented, exploring the effectiveness of various algorithms and neural network architectures to achieve a good root mean square error.