Optical fiber manufacturing method and optical fiber

Patent metadata

Field	Value
Publication number	US-9527765-B2
Application number	US-201314651483-A
Country	US
Kind code	B2
Filing date	Dec 11, 2013
Priority date	Dec 12, 2012
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

There is provided a method for producing a low-loss alkali metal-doped silica core optical fiber having excellent hydrogen resistance. The method for producing the optical fiber according to the present invention includes a drawing step of drawing an optical fiber preform in a drawing furnace to produce a silica glass-based optical fiber including a core region containing an alkali metal with an average concentration of 0.5 atomic ppm or more and a cladding region that surrounds the core region and a heating step of heating the optical fiber in a heating furnace through which the optical fiber drawn from the drawing furnace passes.

First claim

The invention claimed is:

1. A silica glass-based optical fiber comprising a core region containing an alkali metal with an average concentration of 0.5 atomic ppm or more and a cladding region that surrounds the core region,
wherein a transmission loss at a wavelength of 1550 nm is 0.158 dB/km or less, and
a transmission loss increase at a wavelength of 1550 nm is 0.003 dB/km or less, the increase being caused by exposing the optical fiber to a hydrogen atmosphere with a hydrogen partial pressure of 1 kPa at 25° C. for 720 hours.

2. A silica glass-based optical fiber comprising a core region containing an alkali metal with an average concentration of 0.5 atomic ppm or more and a cladding region that surrounds the core region,
wherein a transmission loss at a wavelength of 1550 nm is 0.158 dB/km or less, and
a transmission loss increase at wavelengths of 1560 nm to 1620 nm is 0.005 dB/km or less, the increase being caused by exposing the optical fiber to a hydrogen atmosphere with a hydrogen partial pressure of 1 kPa at 25° C. for 720 hours.

3. The silica glass-based optical fiber according to claim 1 ,
wherein the optical fiber is an optical fiber exposed to a deuterium atmosphere with a deuterium partial pressure of 2 kPa at 40° C. for 24 hours; and a transmission loss increase at a wavelength of 1550 nm is 0.002 dB/km or less, the increase being caused by exposing the optical fiber to a hydrogen atmosphere with a hydrogen partial pressure of 1 kPa at 25° C. for 720 hours.

4. The silica glass-based optical fiber according to claim 2 ,
wherein the optical fiber is an optical fiber exposed to a deuterium atmosphere with a deuterium partial pressure of 2 kPa at 40° C. for 24 hours; and a transmission loss increase at wavelengths of 1560 nm to 1620 nm is 0.003 dB/km or less, the increase being caused by exposing the optical fiber to a hydrogen atmosphere with a hydrogen partial pressure of 1 kPa at 25° C. for 720 hours.

Assignees

• Sumitomo Electric Industries

Inventors

• Haruna Tetsuya
• Hirano Masaaki
• Tamura Yoshiaki
• Nakanishi Tetsuya

Classifications

• C03C2201/23

  containing hydroxyl groups · CPC title

• C03B2205/56

  Annealing or re-heating the drawn fibre prior to coating · CPC title

• C03C3/06 Primary

  with more than 90% silica by weight, e.g. quartz {(C03C3/045 takes precedence)} · CPC title

• C03B2201/50

  doped with alkali metals · CPC title

• C03C2201/50

  containing alkali metals · CPC title