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US 2012/0192594 A1Published application
Optical fiber drawing methods and drawing furnaces
AssigneeFurukawa Electric Col, Ltd.
InventorsNobuaki ORITA, Takashi SUZUKI, Yoshiyuki SAKATA
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Abstract
Drawing methods and drawing furnaces for drawing an optical fiber with small non-circularity by simple drawing system are provided. An optical fiber preform is received into a muffle tube and heated by a primary heater placed to surround the muffle tube. The optical fiber preform is heated such that a starting position of a meniscus portion is higher in its position than the top of the primary heater, wherein the meniscus portion is created at the bottom portion of the optical fiber preform.
Claims4
An optical fiber drawing furnace, comprising:
- a muffle tube to receive an optical fiber preform;
- a primary heater to heat inside of the muffle tube, which is placed around the muffle tube concentrically with the muffle tube;
- and
- a furnace body to accommodate the muffle tube and the primary heater;
- wherein the optical fiber drawing furnace satisfies the relationship 2E≧L≧1.5E where E is the inner diameter of the muffle tube and L is a distance between the highest temperature point and a point, which is 400° C. lower than the highest temperature and located in the upper side of the muffle tube.
2 more elements
Dependencies are inferred from the claim text.