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:
May. 20, 1980
Filed:
Aug. 14, 1978
Tsuneo Suganuma, Tokorozawa, JP;
Koji Ishida, Tokyo, JP;
Shin Satoh, Iruma, JP;
Mamoru Sugie, Hachioji, JP;
Toshio Katsuyama, Kokubunji, JP;
Gyozo Toda, Hino, JP;
Hitachi, Ltd., , JP;
Abstract
A method of producing an optical fiber comprising (i) the step of depositing a glass film of desired refractive index onto the inner wall surface of a quartz tube by the CVD (chemical vapor deposition) process, (ii) the step of heating the quartz tube to a high temperature while the gas of a compound which forms an oxide, enhancing the refractive index of the glass film, in an oxidizing atmosphere at the high temperature is kept flowing into the quartz tube along with an oxidizing gas, (iii) the step of heating and collapsing the quartz tube into a solid rod or the so-called preform, and (iv) the step of heating and drawing the optical fiber preform into the optical fiber. In the optical fiber produced by this method of manufacture, the lowering of the refractive index of the central part of the optical fiber is sharply reduced. At the step (iii), one end of the quartz tube is sealed and a gas is introduced into the tube from the other end so as to slightly raise the internal pressure of the tube, whereby a more favorable result is obtained.