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:
Jan. 27, 1998
Filed:
Aug. 09, 1996
Kouji Okamura, Shimotsuga-gun, JP;
Tadao Arima, Shimotsuga-gun, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A first process of the invention comprises forming two constricted portions (28) at a quartz reaction tube (4), charging a solution of a compound of a rare earth element as a solution into the section between the constricted portions (28) for doping. By this, the doping concentration becomes uniform along the length of an optical fiber preform (30) with defects being rarely produced. This process does not involve any complicated operation. A second process of the invention comprises impregnating a solution in the form of a mist in a soot-like core glass (26) by which it becomes possible to control the doping concentration in high accuracy. A third process of the invention comprises impregnating a solution while controlling the concentration in response to a quantity of a transmitted laser beam through a soot-like core glass (26), by which the doping concentration is ensured independently of the density of the soot-like core glass. A fourth process of the invention comprises repeating formation of a soot-like core glass (26) at different temperatures, by which a distribution of a doping concentration along the radial direction of the core can be arbitrarily set.