| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a glass preform wherein the (J) magnification of the glass preform is set so as to give an optical fiber having a constant wavelength dispersion value and the set (J) magnification can be obtained with a high accuracy. SOLUTION: In this production method, glass particulates are successively deposited on the periphery of a starting glass rod 1, which contains a core rod 1b, for the optical fiber by an OVD (outside vapor phase deposition) method to form a soot layer 3 and the soot layer 3 is transparentized. Before the deposition of glass particulates, the refractive index distribution of the core rod 1b is measured in the longitudinal direction. Basing on the measured refractive index distribution, the target (J) magnification (the outer diameter of the glass preform/the outer diameter of the starting glass rod) distribution is calculated so that the wavelength dispersion value in the longitudinal direction becomes a specified value; thereby, the amount of glass deposit in the longitudinal direction is adjusted so as to obtain the target (J) magnification. COPYRIGHT: (C)2004,JPO
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