Xiaoyuan Dong

US Patent:

6701753, Mar 9, 2004

Filed:

Feb 11, 2001

Appl. No.:

09/781515

Inventors:

Xiaoyuan Dong - Suwanee GA
Siu-Ping Hong - Alpharetta GA

Assignee:

Fitel USA Corp. - Norcross GA

International Classification:

C03B 37025

US Classification:

65412, 65435, 65484

Abstract:

Embodiments of the invention include a method and apparatus for making optical fiber preforms and optical fiber. The method includes the steps of positioning an overclad tube around a preform core rod, heating the overclad tube along the length thereof in the presence of a pressure gradient to collapse onto the preform core to form the overclad optical fiber preform, and adjusting the radial size of a heated portion of the preform core rod and/or the overclad tube to actively match the radial dimensions of the preform core rod along the length thereof with corresponding portions of the overclad tube. The active matching reduces variations in the physical dimensions of the preform core rod and/or the overclad tube, which improves transmission and other performance characteristics of fiber drawn from the created preform, e. g. , by maintaining a relatively constant D/d ratio of the preform.

US Patent:

6460378, Oct 8, 2002

Filed:

Feb 29, 2000

Appl. No.:

09/515227

Inventors:

Xiaoyuan Dong - Suwanee GA 30024
Siu-Ping Hong - Alpharetta GA 30022
Thomas John Miller - Alpharetta GA 30022
Don H Smith - Atlanta GA 30345

International Classification:

C03B 31027

US Classification:

65412, 65435

Abstract:

Embodiments of the invention include a method and apparatus for making a multiple overclad optical fiber preform. The method includes positioning a first overclad tube around a preform core rod, positioning at least one second overclad tube around the first overclad tube, and collectively heating the preform core and the overclad tubes under pressure to collapse the overclad tubes onto the preform core rod thus producing a multiple overclad optical fiber preform. The apparatus includes a preform core rod, a first overclad tube surrounding the preform core rod, and at least one second overclad tube surrounding the first overclad tube. A quartz disc with or without one or more quartz spacers is used for supporting the preform core rod and the first overclad tube within the additional overclad tubes.