MCVD preform central dip reduction by collapse under fluorinated atmosphere

Liegois, M.; Lavanant, G.; Boniort, J.-Y.; Sergent, C. Le

doi:10.1016/0022-3093(82)90068-0

Cited by 6 publications

(2 citation statements)

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“…On the other hand, B 2 O 3 evaporation and its subsequent escape from reaction zone during final stages of deposition results in peak formation at the center of the RI profile. The magnitude of this central dip was reduced by using Freon gas at the initial collapse stage that has been reported to preferentially etch few microns of SiO 2 layer ( Ref 20,21).…”

Section: Change In Refractive Indexmentioning

confidence: 98%

Composition-Property Correlation in B2O3-SiO2 Preform Rods Produced Using Modified Chemical Vapor Deposition Technique

Islam

Saleem

2011

J. of Materi Eng and Perform

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Due to unique optical properties of high birefringent (Hi-Bi) fibers for sensing and coherent optical communications, there is a strong interest in process optimization at preform fabrication and fiber drawing stages. Boron-doped silica cladding acts as stress-applying part resulting in polarization properties of Hi-Bi fibers that are strongly dependent on chemical composition. Using modified chemical vapor deposition (MCVD) technique, B 2 O 3 -doped silica preform rods were synthesized under different precursor gas flow conditions. Qualitative information about B 2 O 3 -SiO 2 system composition was derived from etching behavior in nonbuffered HF solution and subsequent microstructural examination using scanning electron microscope. Significant degree of B 2 O 3 incorporation was seen in case of high BCl 3 :SiCl 4 ratio and mild oxygen-deficient processing conditions. Increasing the B 2 O 3 content to $26 mol% led to a corresponding increase in coefficient of thermal expansion (CTE) to a maximum value of 2.35 ppm/K. The value of refractive index (RI), on the other hand, was found to decrease with increased B 2 O 3 incorporation. A qualitative correlation between B 2 O 3 and SiO 2 system composition and physical properties such as CTE and RI was established.

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Section: Change In Refractive Indexmentioning

confidence: 98%

Composition-Property Correlation in B2O3-SiO2 Preform Rods Produced Using Modified Chemical Vapor Deposition Technique

Islam

Saleem

2011

J. of Materi Eng and Perform

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“…The outer and inner cladding of the fiber are both formed by a triangular array of air holes with the same lattice constant and diameter d. The inner core of the fiber with fixed diameter of 0.5 is composed of low germanium doped silica with a small central index dip which is introduced inevitably into the fiber perfomed by the MCVD process [10] . The refractive index increment of the germanium doped core keeps low (about 0.003, defined as n ) so that both the less transmission losses and higher negative dispersion coefficients can be reached.…”

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confidence: 99%

A novel highly negative dispersion photonic crystal fiber

Lou

Guo

et al. 2009

Optoelectron. Lett.

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Based on the full-vector finite element method, a novel structure of highly negative dispersion photonic crystal fiber with the central index dip in the low germanium doped core is proposed. The highly negative dispersion can be obtained at the wavelength of 1.55 m by adjusting the pitch, the air-hole diameter in the third ring, the germanium doped concentration and the influence of central index dip.

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