Method for manufacturing optical fiber glass preform
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsHiroki Kojima, Dai Inoue
Life of this patent
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Abstract
Provided is a method for manufacturing an optical fiber glass preform in which a refractive index distribution is stable in a longitudinal direction of the glass preform. A method for manufacturing an optical fiber glass preform includes: depositing a porous glass preform by a vapor phase method; and sintering the porous glass preform in a heating region, when sintering the porous glass preform, the porous glass preform being inserted into a vessel of a sintering furnace, and an inside of the vessel being heated with a heater installed on an outer periphery of the vessel to form the heating region. The sintering is started after a surface temperature difference of the porous glass preform in a longitudinal direction is made 50° C. or lower.
Claims19
A method for manufacturing an optical fiber glass preform, the method comprising:
- depositing a porous glass preform by a vapor phase method;
- placing the porous glass preform in a storage immediately after the end of the depositing under a clean atmosphere with a stable temperature for a period of time until a surface temperature difference of the porous glass preform in a longitudinal direction is made 50° C. or lower, and a minimum temperature of a surface of the porous glass preform is made 200° C. or lower and not lower than about 30° C.;
- and
- sintering the porous glass preform in a heating region, when sintering the porous glass preform, the porous glass preform being inserted into a vessel of a sintering furnace, and an inside of the vessel being heated with a heater installed on an outer periphery of the vessel to form the heating region, wherein
- when the sintering is started, the surface temperature difference of the porous glass preform in the longitudinal direction is 50° C. or lower, and wherein when the sintering is started, the minimum temperature of the surface of the porous glass preform is 200° C. or lower and not lower than about 30° C.
A method for manufacturing an optical fiber glass preform, the method comprising:
- depositing a porous glass preform by a vapor phase method;
- placing the porous glass preform in a storage immediately after the end of the depositing under a clean atmosphere with a stable temperature for a period of time until a surface temperature difference of the porous glass preform in a longitudinal direction is made 50° C. or lower, and a minimum temperature of a surface of the porous glass preform is made 200° C. or lower;
- and
- sintering the porous glass preform in a heating region, when sintering the porous glass preform, the porous glass preform being inserted into a vessel of a sintering furnace, and an inside of the vessel being heated with a heater installed on an outer periphery of the vessel to form the heating region, wherein
- when the sintering is started, the surface temperature difference of the porous glass preform in the longitudinal direction is about 20° C., and wherein when the sintering is started, the minimum temperature of the surface of the porous glass preform in the longitudinal direction is about 30° C. and a maximum temperature of the surface of the porous glass preform in the longitudinal direction is about 50° C.
A method for manufacturing an optical fiber glass preform, the method comprising:
- depositing a porous glass preform by a vapor phase method;
- placing the porous glass preform in a storage immediately after the end of the depositing under a clean atmosphere with a stable temperature for a period of time until a surface temperature difference of the porous glass preform in a longitudinal direction is made 50° C. or lower, and a minimum temperature of a surface of the porous glass preform is made 200° C. or lower;
- and
- sintering the porous glass preform in a heating region, when sintering the porous glass preform, the porous glass preform being inserted into a vessel of a sintering furnace, and an inside of the vessel being heated with a heater installed on an outer periphery of the vessel to form the heating region, wherein
- when the sintering is started, the surface temperature difference of the porous glass preform in the longitudinal direction is about 40° C., and wherein when the sintering is started, the minimum temperature of the surface of the porous glass preform in the longitudinal direction is about 50° C. and a maximum temperature of the surface of the porous glass preform in the longitudinal direction is about 90° C.
Dependencies are inferred from the claim text.