Ytterbium-doped glass-ceramic fiber
Biswas, Shuvro Sojol (2026)
2026
Master's Programme in Photonics Technologies
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Hyväksymispäivämäärä
2026-05-06
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202605055056
https://urn.fi/URN:NBN:fi:tuni-202605055056
Tiivistelmä
Glasses doped with rare-earth ions such as Yb3+ are widely used in various technological ap-plications related to photonics due to their amorphous structure and compositional versatility. Phosphate glasses are of particular interest among different glass families due to their low melt-ing temperatures, high rare-earth solubility, and favorable optical properties, which make them promising candidates for optical fibers and photonic devices. The glass composition needs to be thermally stable, as it ensures resistance to crystallization during fiber drawing. Homogenously distributed nanocrystals inside glass-ceramics provide a low phonon energy environment and en-hance the spectroscopic performance and improve the mechanical strength.
The aim of this study is to investigate the influence of Nb2O5 addition on the structural, ther-mal, optical, and spectroscopic properties of Yb-doped oxyfluorophosphate glasses and to evalu-ate their suitability for transparent glass-ceramic formation using thermal treatment and for the fabrication of optical fiber. Glasses with compositions (75 − x)NaPO3 – xNb2O5 – 25CaF2 (mol%), where x = 0, 5, and 10, doped with 1 mol% Yb2O3 were synthesized using the conventional melt-quenching technique. Controlled heat treatment was applied to produce transparent glass-ceramics through nucleation and crystal growth processes. Selected compositions were further processed into preforms and drawn into optical fibers.
The prepared materials were characterized using various techniques, including density measure-ments, differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron micros-copy (SEM), Raman and FTIR spectroscopies, refractive index measurements, optical absorp-tion, and spectroscopy. From the structural analysis, the addition of Nb2O5 is expected to modify the phosphate glass network by forming Nb–O–P and Nb–O–Nb linkages, thereby increasing the structural rigidity. Improved thermal stability against crystallization was also observed with an in-crease in x as well as an enhancement of the resistance to crystallization, which is beneficial for fiber drawing. Controlled heat treatment resulted in the formation of transparent glass-ceramics containing CaF2 nanocrystalline phases. The glass-ceramic samples exhibited suitable absorption and emission characteristics for ytterbium-based photonic applications. Optical fibers were suc-cessfully drawn from both glass and glass-ceramic preforms, and light propagation and emission was observed from the glass and glass-ceramic fibers, demonstrating the feasibility of fabricating Yb-doped oxyfluorophosphate glass-ceramic fibers.
Overall, this study shows that Nb2O5-modified Yb-doped oxyfluorophosphate glass and glass-ceramics are promising materials for optical fiber and photonic device applications, particularly in near-infrared laser and amplifier systems.
The aim of this study is to investigate the influence of Nb2O5 addition on the structural, ther-mal, optical, and spectroscopic properties of Yb-doped oxyfluorophosphate glasses and to evalu-ate their suitability for transparent glass-ceramic formation using thermal treatment and for the fabrication of optical fiber. Glasses with compositions (75 − x)NaPO3 – xNb2O5 – 25CaF2 (mol%), where x = 0, 5, and 10, doped with 1 mol% Yb2O3 were synthesized using the conventional melt-quenching technique. Controlled heat treatment was applied to produce transparent glass-ceramics through nucleation and crystal growth processes. Selected compositions were further processed into preforms and drawn into optical fibers.
The prepared materials were characterized using various techniques, including density measure-ments, differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron micros-copy (SEM), Raman and FTIR spectroscopies, refractive index measurements, optical absorp-tion, and spectroscopy. From the structural analysis, the addition of Nb2O5 is expected to modify the phosphate glass network by forming Nb–O–P and Nb–O–Nb linkages, thereby increasing the structural rigidity. Improved thermal stability against crystallization was also observed with an in-crease in x as well as an enhancement of the resistance to crystallization, which is beneficial for fiber drawing. Controlled heat treatment resulted in the formation of transparent glass-ceramics containing CaF2 nanocrystalline phases. The glass-ceramic samples exhibited suitable absorption and emission characteristics for ytterbium-based photonic applications. Optical fibers were suc-cessfully drawn from both glass and glass-ceramic preforms, and light propagation and emission was observed from the glass and glass-ceramic fibers, demonstrating the feasibility of fabricating Yb-doped oxyfluorophosphate glass-ceramic fibers.
Overall, this study shows that Nb2O5-modified Yb-doped oxyfluorophosphate glass and glass-ceramics are promising materials for optical fiber and photonic device applications, particularly in near-infrared laser and amplifier systems.