Reduction of optical fiber cane/preform deformation during consolidation

A technology of preforms and optical fiber blanks, applied in glass fiber products, glass deposition furnaces, manufacturing tools, etc., can solve problems such as uncertainty, dopant distribution changes, manufacturing process errors, etc., achieve good optical fiber properties, reduce Deformation, the effect of increasing the usable length

CN101657389BActive Publication Date: 2012-09-26CORNING INC
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2012-09-26

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Abstract

According to an embodiment of the invention a method of manufacturing optical fiber cane comprises the steps of: (i) providing a core rod manufactured of relatively low viscosity glass; (ii) depositing SiO2 based soot around the core rod to form a soot preform, the soot being of relatively high viscosity material such that the softening point of the low viscosity glass is at least 200 DEG C lower than the viscosity of the high viscosity outer core region; and (iii) consolidating the soot of the soot perform by exposure to hot zone at temperatures of 1000 DEG C-1600 DEG C. The soot is consolidated by heating the outer portion of the soot perform at a relatively fast heating rate, the heating rate being sufficient to densify the soot, so as to render the densified material with enough rigidity to confine the heated core rod and to prevent the heated core rod from puddling.
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Description

technical field

[0001] The present invention relates generally to the formation of optical fiber canes having a low viscosity core, and more particularly to the formation of optical fiber core canes having an alkali metal doped inner core. Background technique

[0002] The manufacture of an optical fiber core blank comprises depositing glass soot on an alkali-doped glass rod as an inner core, forming a porous soot preform, and then allowing the preform to sufficiently solidify the soot The speed passes through the heating zone to consolidate the soot and form the outer core.

[0003] During consolidation of the outer core, the preform shrinks radially and axially. We observed bulging or deformation at the bottom of the inner mandrel relative to the outer core area. This phenomenon has not been observed previously upon consolidation of soot deposited on other types of core preforms (eg, germania-doped silica preforms used to make standard single-mode fiber preforms). We sp...

Examples

Embodiment 1

[0043] Figure 7 Shown is a first exemplary method 400 of making an alkali metal doped optical fiber by diffusing an alkali metal oxide into a suitable silica glass article as a precursor inner core preform in accordance with an embodiment of the present invention Preform (the fiber is then made). refer to Figure 7 and Figure 8 , which illustrate and describe the first step 401 of the method 400 (forming a silica-containing soot tube). see Figure 8 , which diagrammatically illustrates a conventional external vapor deposition process that uses at least one soot burner 156 to deposit layers of silica soot 162 on a mandrel 144 to form a soot preform 160. The formed soot preform is then dried using standard chlorine drying techniques (step 403). In this embodiment, the soot is then mixed with a fluorine-containing compound (such as SiF 4 ) atmosphere for a certain period of time to dope the soot with fluorine (step 405), the temperature and time being sufficient to remove...