The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 04, 2002
Filed:
Aug. 28, 2001
Katsuya Nagayama, Yokohama, JP;
Yuichi Ohga, Yokohama, JP;
Tatsuhiko Saitoh, Yokohama, JP;
Shinji Ishikawa, Yokohama, JP;
Ichiro Tsuchiya, Yokohama, JP;
Takenori Uchiyama, Yokohama, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
An optical fiber preform having a viscosity ratio R&eegr;=&eegr; /&eegr; of 2.5 or less between the core average viscosity &eegr; and the total average viscosity &eegr; is prepared, and is drawn by a drawing furnace so as to yield an optical fiber which is then heated to a temperature within a predetermined range so as to be annealed by a heating furnace disposed downstream the drawing furnace Here, upon annealing in the heating furnace the fictive temperature Tf within the optical fiber lowers, thereby reducing the Rayleigh scattering loss. At the same time, the viscosity ratio condition of R&eegr;≦2.5 restrains the stress from being concentrated into the core, thereby lowering the occurrence of structural asymmetry loss and the like. Hence, an optical fiber which can reduce the transmission loss caused by the Rayleigh scattering loss and the like as a whole, and a method of making the same can be obtained.