# US 8,464,557 B2 · Method of producing optical fiber preform and optical fiber

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- Number: US 8,464,557 B2
- Document ID: US8464557B2
- Status: Granted
- Kind: B2
- Application number: 13/279,850
- Filed: 2011-10-24
- Published: 2012-05-17
- Granted: 2013-06-18
- Earliest claimed: 2010-11-12
- Assignees: Furukawa Electric Co., Ltd.
- Applicants: Taeko Shibuta; Tadashi Takahashi; Takeshi Yagi
- Inventors: Taeko Shibuta; Tadashi Takahashi; Takeshi Yagi
- Web page: https://patentgrep.com/patent/US8464557B2

## CPC

- C03B 37/01231: {to form a longitudinal hole, e.g. by drilling}
- C03B 37/01205: {starting from tubes, rods, fibres or filaments (C03B37/014 takes precedence)}
- C03B 37/01446: {Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering (C03B37/01853 takes precedence)}
- C03B 37/027: Fibres composed of different sorts of glass, {e.g. glass optical fibres}(C03B37/0253, C03B37/028 take precedence)
- C03B 37/02763: {Fibres having axial variations, e.g. axially varying diameter, material or optical properties (rotational spin C03B37/02745)}
- C03B 2203/14: Non-solid, i.e. hollow products, e.g. hollow clad or with core-clad interface
- C03B 2205/10: pressurised
- C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES

## Abstract

A method of producing an optical fiber preform includes preparing a glass preform that has a hole extending in a longitudinal direction formed on one end of the glass preform in such a manner that a length of the hole is equal to or less than half of an entire length of the glass preform, synthesizing a porous glass preform by depositing glass particles on an outer circumference of the glass preform having the hole formed on the end, and sintering the porous glass preform after arranging the porous glass preform in such a manner that the end having the hole formed thereon points downward and the hole is open to the air.

## Claims

### Claim 1

A method of producing an optical fiber preform, the method comprising:
preparing a glass preform that has a hole extending in a longitudinal direction formed on one end of the glass preform in such a manner that a length of the hole is equal to or less than half of an entire length of the glass preform;
synthesizing a porous glass preform by depositing glass particles on an outer circumference of the glass preform having the hole formed on the end; and
sintering the porous glass preform after arranging the porous glass preform in such a manner that the end having the hole formed thereon points downward and the hole is open to air.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the length of the hole is equal to or less than one third of the entire length of the glass preform.

### Claim 3 (depends on 1)

A method of producing an optical fiber, the method comprising:
arranging the optical fiber preform that is produced by the production method of claim 1 in such a manner that the end having the hole formed thereon points upward; and
drawing the other end of the optical fiber preform on which the hole is not formed.

### Claim 4 (depends on 2)

A method of producing an optical fiber, the method comprising:
arranging the optical fiber preform that is produced by the production method of claim 2 in such a manner that the end having the hole formed thereon points upward; and
drawing the other end of the optical fiber preform on which the hole is not formed.