Tunable Rayleigh scattering in low-loss Sr-based nanoparticle-doped optical fibers: Controlling nanoparticle features throughout preform and fiber fabrication

Alkaline earth nanoparticles in-situ grown on silica-based optical fibers are promising for distributed sensing applications. To date, only Ca-based nanoparticles have been proven to be suitable compositions for long-range distributed fiber sensing based on Rayleigh scattering enhancement. Herein, we extend this approach and demonstrate for the first time that Sr-based nanoparticles grown in-situ in silica-based optical fiber cores are suitable to fabricate low-loss Rayleigh scattering enhanced nanoparticle-doped optical fibers with tunable performance. A thorough microstructural study about the influence of preform and fiber manufacture conditions on the nanoparticle characteristics reveal their great impact, and the possibility of considerably tailoring their features throughout fabrication process. This simultaneously determines the tunability of the induced Rayleigh scattering and optical attenuation. Consequently, we improve the state-of-art trade-off between Rayleigh scattering enhancement and two-way optical losses, showing values of 26.4–43.8 dB, regarding a SMF-28, and 0.2–5.1 dB/m, respectively. This allows long-range sensing lengths from 8.6 m to 132 m. Our findings provide new insights into in-situ grown alkaline earth nanoparticles and establish solid guidelines to tailor nanoparticle features in nanoparticle-doped optical fibers, which open new prospects in optical fiber community.