Abstract: The method, in which base material ingot 1 is heated and softened in an electric furnace 3, drawn with a pair of pinch roller 6 and 6, and elongated to make base material rod 7 having a smaller diameter than the ingot, features: forming either a roller groove 11 having a curvature radius which is larger than the outer diameter of the base material rod 7 or a V-shaped roller groove 11 having the cross section consisting of straight lines on the surface of the pinch roller 6 made of metal; nipping with the facing roller grooves 11 and 11 respectively formed on the surfaces of a pair of said pinch rollers 6 and 6; and drawing said base material rod.

Abstract: When forming a taper portion on an end of a glass base material for manufacturing an optical fiber, the taper portion is formed by fusing the glass base material from a modified point after modifying a center-line displacement amount of a fusing point for a center line of the glass base material to a value not more than a predetermined numeric value. Moreover, in a glass base material for drawing having an effective straight base with an average outside diameter D and a taper portion on one end of the effective straight base, when the glass base material is attached to a drawing apparatus, a ratio ?/D between the average outside diameter D and a taper portion distortion ? is ?/D<=0.03, and the taper portion distortion ? is expressed with a maximum value of a center-line displacement amount of the glass base material between an effective straight base end from the taper portion and a distortion evaluating end of the taper portion.

Abstract: To decrease the manufacturing cost and the transmission loss of precursor of optical fiber or preform for optical fiber, a method of manufacturing glass base material includes: forming porous glass base material which includes a dopant added core part, and an inner clad layer surrounding said core part and having a lower refractive index than the core part; transforming said porous glass base material into clear glass to be provided as a core ingot; heating and elongating said core ingot in the axial direction in an electric furnace to make a core rod; and forming an outer clad layer surrounding said core rod.

Abstract: The method, in which base material ingot 1 is heated and softened in an electric furnace 3, drawn with a pair of pinch roller 6 and 6, and elongated to make base material rod 7 having a smaller diameter than the ingot, features: forming either a roller groove 11 having a curvature radius which is larger than the outer diameter of the base material rod 7 or a V-shaped roller groove 11 having the cross section consisting of straight lines on the surface of the pinch roller 6 made of metal; nipping with the facing roller grooves 11 and 11 respectively formed on the surfaces of a pair of said pinch rollers 6 and 6; and drawing said base material rod.

Abstract: A method for manufacturing an optical fiber comprises setting a heating condition for heating a glass rod, which is a parent material of the optical-fiber, and an elongating speed of the glass rod based on a prescribed numerical value which changes with a progress of elongation of the glass rod; heating and elongating the glass rod to generate a preform based on the heating condition and the elongating speed which are set by the setting; and drawing the preform to a filament-like form by further heating the preform to generate the optical fiber.

Abstract: A method for manufacturing an optical fiber comprises setting a heating condition for heating a glass rod, which is a parent material of the optical fiber, and an elongating speed of the glass rod based on a prescribed numerical value which changes with a progress of elongation of the glass rod; heating and elongating the glass rod to generate a preform based on the heating condition and the elongating speed which are set by the setting; and drawing the preform to a filament-like form by further heating the preform to generate the optical fiber.

Abstract: A method for manufacturing a glass rod (106), which is a parent material of an optical fiber (350), comprising: adjusting a vertical inclination of a standard rod (138) having a predetermined straightness; and heating and elongating a base material (102), which is a parent material of the glass rod (106), along an axis of the standard rod (138), the vertical inclination of which is adjusted, to generate the glass rod (106).

Abstract: A method for manufacturing an optical fiber comprises setting a heating condition for heating a glass rod, which is a parent material of the optical fiber, and an elongating speed of the glass rod based on a prescribed numerical value which changes with a progress of elongation of the glass rod; heating and elongating the glass rod to generate a preform based on the heating condition and the elongating speed which are set by the setting; and drawing the preform to a filament-like form by further heating the preform to generate the optical fiber.

Abstract: A method for manufacturing a glass rod (106), which is a parent material of an optical fiber (350), comprising: adjusting a vertical inclination of a standard rod (138) having a predetermined straightness; and heating and elongating a base material (102), which is a parent material of the glass rod (106), along an axis of the standard rod (138), the vertical inclination of which is adjusted, to generate the glass rod (106).

Abstract: The glass base material drawing apparatus for heating and drawing a glass base material has a storage unit for storing the glass base material having an opening unit that is opened along the longitudinal direction of the storage unit when the glass base material is placed inside the storage unit, a heating unit for heating the glass base material that has been stored inside the storage unit via the opening unit, and a pull-out unit for pulling out the glass base material heated by the heating unit. The opening unit may be opened in such a manner that the glass base material is moved from a side direction of the storage unit into the interior of the storage unit. A main axis for supporting the glass base material is connected to the glass base material. The storage unit may have a penetration hole through which the main axis is inserted when the opening unit is closed.

Abstract: A method for manufacturing an optical fiber comprises setting a heating condition for heating a glass rod, which is a parent material of the optical fiber, and an elongating speed of the glass rod based on a prescribed numerical value which changes with a progress of elongation of the glass rod; heating and elongating the glass rod to generate a preform based on the heating condition and the elongating speed which are set by the setting; and drawing the preform to a filament-like form by further heating the preform to generate the optical fiber.

Abstract: A method for manufacturing an optical fiber comprises setting a heating condition for heating a glass rod, which is a parent material of the optical fiber, and an elongating speed of the glass rod based on a prescribed numerical value which changes with a progress of elongation of the glass rod; heating and elongating the glass rod to generate a preform based on the heating condition and the elongating speed which are set by the setting; and drawing the preform to a filament-like form by further heating the preform to generate the optical fiber.

Abstract: A method for manufacturing an optical fiber comprises setting a heating condition for heating a glass rod, which is a parent material of the optical fiber, and an elongating speed of the glass rod based on a prescribed numerical value which changes with a progress of elongation of the glass rod; heating and elongating the glass rod to generate a preform based on the heating condition and the elongating speed which are set by the setting; and drawing the preform to a filament-like form by further heating the preform to generate the optical fiber.

Abstract: A method for manufacturing an optical fiber comprises setting a heating condition for heating a glass rod, which is a parent material of the optical fiber, and an elongating speed of the glass rod based on a prescribed numerical value which changes with a progress of elongation of the glass rod; heating and elongating the glass rod to generate a preform based on the heating condition and the elongating speed which are set by the setting; and drawing the preform to a filament-like form by further heating the preform to generate the optical fiber.

Abstract: A method for manufacturing an optical fiber comprises setting a heating condition for heating a glass rod, which is a parent material of the optical fiber, and an elongating speed of the glass rod based on a prescribed numerical value which changes with a progress of elongation of the glass rod; heating and elongating the glass rod to generate a preform based on the heating condition and the elongating speed which are set by the setting; and drawing the preform to a filament-like form by further heating the preform to generate the optical fiber.

Abstract: A method for manufacturing an optical fiber comprises setting a heating condition for heating a glass rod, which is a parent material of the optical fiber, and an elongating speed of the glass rod based on a prescribed numerical value which changes with a progress of elongation of the glass rod; heating and elongating the glass rod to generate a preform based on the heating condition and the elongating speed which are set by the setting; and drawing the preform to a filament-like form by further heating the preform to generate the optical fiber.