Effect of H2/O2 ratio on the GeO2 concentration profile in SiO2:GeO2 glass preforms prepared by vapor-phase axial deposition

Cuevas, Raúl; Gusken, Edmilton; Sekiya, Edson Haruhico; Ogata, Daniela Y; Torikai, Delson; Suzuki, Carlos K.

doi:10.1016/s0022-3093(00)00134-4

Cited by 8 publications

(4 citation statements)

References 6 publications

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“…7 shows the germanium doping profiles from the lower and upper extremity and the center of the preform. The higher GeO 2 concentration of the outer diameter region in comparison to the center of the preform is due to the deposition of the crystalline phase of GeO 2 induced by a lower temperature of deposition [19], [20]. Dehydration with Cl 2 gas was not considered in these preforms, which explains the effect of noelimination of the GeO 2 crystalline phase [21].…”

Section: Correlation Between Preform Bottom Profile and Germaniumentioning

confidence: 99%

Correlation study between VAD preform deposition surface and Germanium doping profiles

Santos

Ono

Gusken

et al. 2006

J. Lightwave Technol.

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The refractive index profile of germanium doped preforms for optical fibers is determined by the radial distribution of germanium concentration. Knowing that there is a correlation between the germanium doping profile and the deposition surface profile of vapor-phase axial deposition (VAD) preforms, the study of this correlation has been carried out in order to estimate, indirectly, the refractive index profile of VAD preforms for optical fibers during the deposition stage. This correlation was studied through the parameterization of the preform deposition surface using two parameters: the power law index profile that best fits the preform bottom profile (α) and the axial distance from the bottom tip to a reference height (h). A range of values of these parameters to produce VAD preforms with standard and special doping profiles has been presented. Preforms with triangular index profile can be fabricated with α and h values of about 2.0 and 5.0 mm, respectively, and preforms with parabolic index profiles can be produced with α and h values of about 2.0 and 4.0 mm, respectively.

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Section: Correlation Between Preform Bottom Profile and Germaniumentioning

confidence: 99%

Correlation study between VAD preform deposition surface and Germanium doping profiles

Santos

Ono

Gusken

et al. 2006

J. Lightwave Technol.

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“…Figure a shows a conceptual diagram of the VAD method . As shown in the leftmost schematic, SiCl 4 and GeCl 4 are injected into oxy–hydrogen gas burners, and fine SiO 2 and GeO 2 particles are produced by the flame hydrolysis reaction given below, and are then deposited onto the end surface of the seed SiO 2 glass rod: The seed rod is pulled upward and rotated during chemical deposition, producing a porous preform (middle picture in Figure a). The inner and outer deposited regions of the porous preform become the core (SiO 2 –GeO 2 ) and cladding (SiO 2 ), respectively.…”

mentioning

confidence: 99%

“…1 Figure 1a shows a conceptual diagram of the VAD method. 1 As shown in the leftmost schematic, SiCl 4 and GeCl 4 are injected into oxy−hydrogen gas burners, and fine SiO 2 and GeO 2 particles are produced by the flame hydrolysis reaction 2 given below, and are then deposited onto the end surface of the seed SiO 2 glass rod:…”

mentioning

confidence: 99%

Nanoscale Phase-Separated Structure in Core–Shell Nanoparticles of SiO₂–Si_1–xGe_xO₂ Glass Revealed by Electron Microscopy

Kubo

Yonezawa

2017

Anal. Chem.

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SiO-based optical fibers are indispensable components of modern information communication technologies. It has recently become increasingly important to establish a technique for visualizing the nanoscale phase-separated structure inside SiO-GeO glass nanoparticles during the manufacturing of SiO-GeO fibers. This is because the rapidly increasing price of Ge has made it necessary to improve the Ge yield by clarifying the detailed mechanism of Ge diffusion into SiO. However, direct observation of the internal nanostructure of glass particles has been extremely difficult, mainly due to electrostatic charging and the damage induced by electron and X-ray irradiation. In the present study, we used state-of-the-art scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and energy dispersive X-ray spectroscopy (EDX) to examine cross-sectional samples of SiO-GeO particles embedded in an epoxy resin, which were fabricated using a broad Ar ion beam and a focused Ga ion beam. These advanced techniques enabled us to observe the internal phase-separated structure of the nanoparticles. We have for the first time clearly determined the SiO-SiGeO core-shell structure of such particles, the element distribution, the degree of crystallinity, and the quantitative chemical composition of microscopic regions, and we discuss the formation mechanism for the observed structure. The proposed imaging protocol is highly promising for studying the internal structure of various core-shell nanoparticles, which affects their catalytic, optical, and electronic properties.

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“…A flutuação de concentração é diretamente proporcional à concentração do dopante. Quanto mais redutora for a chama, menor a taxa de deposição de GeO 2 na preforma porosa, Cuevas (2000).…”

Section: Influência Da Razão H 2 /O 2 Em Preforma Porosa Puraunclassified

Sintese e caracterização de nanovidros de silica para preforma de fibra optica

Tomiyama¹

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Ao meu orientador Prof. Dr. Carlos K. Suzuki, pela escolha do tema e pela orientação segura ao longo do desenvolvimento deste trabalho. Agradeço também pelas oportunidades criadas de interação com especialistas internacionais, na área de deposição axial fase vapor (VAD), para síntese de nanovidros, o que permitiu um aprofundamento no tema. Agradeço também pela valiosa chance que me foi concedida pelo orientador em desenvolver experimentos no SPring-8, Japão.A Eduarno Ono, pela amizade, dedicação, incansável ajuda, e pela inestimável colaboração na análise, redação e revisão deste trabalho.Ao Raul Cuevas, pelas discussões, sugestões e colaboração em todos os estágios de análise dos dados, que em muito contribuíram no desenvolvimento deste trabalho.

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Effect of H2/O2 ratio on the GeO2 concentration profile in SiO2:GeO2 glass preforms prepared by vapor-phase axial deposition

Cited by 8 publications

References 6 publications

Correlation study between VAD preform deposition surface and Germanium doping profiles

Correlation study between VAD preform deposition surface and Germanium doping profiles

Nanoscale Phase-Separated Structure in Core–Shell Nanoparticles of SiO₂–Si_1–xGe_xO₂ Glass Revealed by Electron Microscopy

Sintese e caracterização de nanovidros de silica para preforma de fibra optica

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Effect of H2/O2 ratio on the GeO2 concentration profile in SiO2:GeO2 glass preforms prepared by vapor-phase axial deposition

Cited by 8 publications

References 6 publications

Correlation study between VAD preform deposition surface and Germanium doping profiles

Correlation study between VAD preform deposition surface and Germanium doping profiles

Nanoscale Phase-Separated Structure in Core–Shell Nanoparticles of SiO2–Si1–xGexO2 Glass Revealed by Electron Microscopy

Sintese e caracterização de nanovidros de silica para preforma de fibra optica

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Nanoscale Phase-Separated Structure in Core–Shell Nanoparticles of SiO₂–Si_1–xGe_xO₂ Glass Revealed by Electron Microscopy