Optical fiber parent material and method for manufacturing optical fiber

Abstract

The present invention is an optical fiber parent material provided with a columnar section having a substantially constant radius r, and a tapered section positioned adjacent to the columnar section in the length direction, the radius of the tapered section decreasing along the length direction, the tapered section having a first tapered section having a portion in which the radius thereof varies between 0.9r and 0.6r, and a second tapered section having a portion in which the radius thereof varies between 0.4r and 0.15r, the first tapered section contracting in radius so as to form a maximum angle Theta 1 with the columnar section of between 40 and 60 degrees in the portion where the radius of the first tapered section varies between 0.9r and 0.6r, the second tapered section contracting in radius so as to form a maximum angle Theta 2 with the center axis in the length direction of between 5 and 30 degrees in the portion where the radius of the second tapered section varies between 0.4r and 0.15r, and the volume of the tapered section being 45% or less of the volume of a column having the same length and the same outside diameter as the maximum outside diameter of the tapered section.

Description

technical field [0001] The invention relates to an optical fiber base material and a method for manufacturing an optical fiber. Background technique [0002] One end of an optical fiber base material made of glass is heated and melted in a drawing heating furnace, and the glass optical fiber is drawn from this end, and a coating made of resin or the like is formed on the outer periphery of the drawn glass optical fiber using a drawing die, thereby manufacturing an optical fiber . [0003] However, the tip portion of the optical fiber preform may include a defective portion in which the ratio of the outer diameter of the core to the outer diameter of the clad portion does not meet the specifications. The glass optical fiber drawn from the tip portion as described above cannot be used as a product because the core diameter and the cladding diameter do not meet the specifications. The tip portion of the above-mentioned optical fiber preform is used as a drawing for adjusting ...

AI Technical Summary

Problems solved by technology

[0003] However, the tip portion of the optical fiber preform may include a defective portion in which the ratio of the outer diameter of the core to the outer diameter of the cladding does not meet the specifications.

The glass optical fiber drawn from the above-mentioned tip part cannot be used as a product because the core diameter and cladding diameter do not meet the specifications.

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