Optical fiber laser system for torsion measurement using a three-core fiber and a nanocrystal-based reflector

We report a novel and highly sensitive torsion sensor that integrates a multicore fiber (MCF) within a Sagnac interferometer so that the same MCF segment serves as both the reflective element and the sensing head of a fiber-ring laser. The laser architecture incorporates a distributed reflector impl...

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Detalles Bibliográficos
Autores: Correa Serrano, Ángel Ignacio, Vento Álvarez, José Raúl, Galarza Galarza, Marko, Sánchez González, Arturo, Dauliat, Romain, Jamier, Raphael, Roy, Philippe, Humbert, Georges, Pérez Herrera, Rosa Ana, López-Amo Sáinz, Manuel
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2025
País:España
Institución:Universidad Pública de Navarra
Repositorio:Academica-e. Repositorio Institucional de la Universidad Pública de Navarra
OAI Identifier:oai:dnet:academicae__::e0e709cb159b8ded1efcd19f6bc45f15
Acceso en línea:https://hdl.handle.net/2454/56706
Access Level:acceso abierto
Palabra clave:Sagnac interferometer
Multicore optical fiber
Torsion sensor
Nanocrystals
Neural network
Descripción
Sumario:We report a novel and highly sensitive torsion sensor that integrates a multicore fiber (MCF) within a Sagnac interferometer so that the same MCF segment serves as both the reflective element and the sensing head of a fiber-ring laser. The laser architecture incorporates a distributed reflector implemented as a ZnGa₂O₄-nanocrystal-doped fiber section, which enhances overall system performance. The device exhibits high torsional responsivity over 0°–150°, with distinct behavior across sub-ranges: in 0°–50°, phase analysis yields a sensitivity of 0.08 rad/° with R² = 0.991; in 88°–150°, amplitude analysis—under the ring-laser configuration—shows an improvement in sensitivity from 0.2 to 0.5 dBm/° (R² = 0.995). In the intermediate interval (50°–88°) neither phase nor power varies monotonically, so a function-fitting neural network was employed to bridge this gap, achieving a root-mean-square error of 0.06°. The system attains an angular resolution of 0.8°, ensuring accurate torsion estimation across the entire measurement span.