Claims
- 1. A method for producing an optical fiber porous preform having a center core comprising SiO.sub.2 and GeO.sub.2 and a peripheral layer comprising SiO.sub.2 and GeO.sub.2, wherein the peripheral layer has a GeO.sub.2 concentration which is smaller than that of the center core, comprising the steps of:
- (a) synthesizing glass soot particles from a first double-layer flame burner to form a surface of the preform by:
- (i) supplying SiCl.sub.4 and GeCl.sub.4 to an inner flame of the first double layer flame burner; and
- (ii) supplying SiCl.sub.4 to an outer flame of the first double-layer flame burner, wherein the flow rate of the SiCl.sub.4 supplied to the outer flame is 3 to 6 times the flow rate of the GeCl.sub.4 supplied to the inner flame;
- (b) synthesizing glass soot particles from a second flame burner to form the center core of the preform by supplying SiCl.sub.4 and GeCl.sub.4 to the flame of the burner; and
- (c) depositing the generated glass soot particles on the lower end of a rotating starting member and growing the porous preform by:
- directing the first double-layer flame burner to the surface of the preform; and
- directing the second flame burner to the center core of the preform.
- 2. The method of claim 1, wherein:
- the step of synthesizing soot from a double-layer flame burner is synthesizing soot from a multi-port burner; and
- the step of synthesizing soot from a flame burner to form a core of the preform is synthesizing soot from a single flame burner.
- 3. A method according to claim 1, wherein the second flame burner is a single flame burner.
Priority Claims (1)
Number |
Date |
Country |
Kind |
1-218599 |
Aug 1989 |
JPX |
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Parent Case Info
This is a continuation of application Ser. No. 07/568,779, filed on Aug. 17, 1990, which was abandoned upon the filing hereof.
US Referenced Citations (6)
Foreign Referenced Citations (3)
Number |
Date |
Country |
62-87428 |
Apr 1987 |
JPX |
62-252334 |
Apr 1988 |
JPX |
62-297238 |
Jun 1988 |
JPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
568779 |
Aug 1990 |
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