Method of manufacturing preforms for optical fibres having low water peak

Patent metadata

Field	Value
Publication number	US-9416045-B2
Application number	US-201214758018-A
Country	US
Kind code	B2
Filing date	Dec 28, 2012
Priority date	Dec 28, 2012
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

A method of manufacturing an optical fibre preform comprising: providing a glass core rod comprising a central core region of radius a and an inner clad region of external radius b to define a first core-to-clad ratio a/b; forming an intermediate glass preform comprising an intermediate clad region surrounding the inner clad region of the glass rod and having an external radius c to define a second core-to-clad ratio a/c, and overcladding the intermediate glass preform by forming an overclad region surrounding the intermediate clad region to form an optical fibre preform, wherein the first core-to-clad ratio a/b is equal to or less than 0.40 and the second core-to-clad ratio a/c is of from 0.20 to 0.25.

First claim

The invention claimed is:

1. A method of manufacturing an optical fibre preform comprising:
providing a glass core rod comprising a central core region of radius a and an inner clad region of external radius b to define a first core-to-clad ratio a/b;
forming an intermediate glass preform comprising an intermediate clad region surrounding the inner clad region of the glass rod and having an external radius c to define a second core-to-clad ratio a/c, and
overcladding the intermediate glass preform by forming an overclad region surrounding the intermediate clad region to form an optical fibre preform,
wherein the first core-to-clad ratio a/b is equal to or less than 0.40 and the second core-to-clad ratio a/c is of from 0.20 to 0.25.

2. The method of claim 1 , wherein a/b is of from 0.34 to 0.40.

3. The method of claim 1 , wherein a/b is of from 0.38 to 0.40.

4. The method of claim 1 , wherein forming an intermediate glass preform comprises:
depositing soot material around the glass core rod by a flame hydrolysis process to form a soot intermediate clad layer, and
heating to consolidate the deposited soot intermediate clad layer to form an intermediate glass preform.

5. The method of claim 4 , wherein the soot material forming a soot intermediate clad layer is silica soot.

6. The method of claim 4 , wherein the flame hydrolysis deposition process is an outside vapour deposition process.

7. The method of claim 1 , wherein the inner clad region is of pure silica.

8. The method of claim 1 , wherein overcladding the intermediate glass preform comprises:
depositing soot material around the intermediate glass preform by a flame hydrolysis process to form a soot overclad layer, and
heating to consolidate the soot overclad layer so as to form an optical fibre preform.

9. The method of claim 8 , wherein the flame hydrolysis deposition process is an outside vapour deposition process.

10. A method of manufacturing an optical fibre comprising:
forming an optical fibre preform according to claim 1 , and
drawing the optical fibre preform to fabricate an optical fibre.

Assignees

• Prysmian Spa

Inventors

• Adigrat Antonio
• Caronna Valeria
• Cocchini Franco
• Collaro Antonio
• Grieco Stefano
• Nivelli Ida

Classifications

• C03B37/014 Primary

  made entirely or partially by chemical means {, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD] (C03C17/02 takes precedence)} · CPC title

• C03B2203/24

  Single mode [SM or monomode] · CPC title

• G02B6/02

  Optical fibres with cladding {with or without a coating} · CPC title

• C03B2203/23

  Double or multiple optical cladding profiles · CPC title

• C03B37/027

  Fibres composed of different sorts of glass, {e.g. glass optical fibres}(C03B37/0253, C03B37/028 take precedence) · CPC title