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:
Apr. 04, 1995
Filed:
Jan. 25, 1994
Tsuneo Mori, Gunma, JP;
Kazuo Koya, Gunma, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
In an optical fiber coupler comprising a plurality of optical fibers bundled together and a light-coupling portion which is formed by partially fusing and drawing these bundled fibers and which permits branching of light rays incident upon one of these fibers into the other fibers at a predetermined branching ratio, the optical fiber coupler has a difference between the branching ratio thereof determined immediately after the fusing and drawing operation and that determined after accommodating the coupler in a protective case and then adhering it to the case, equal to or less than 5%. Such an optical fiber coupler can be produced by bundling a plurality of optical fibers 1 and 2, fusing and drawing a part of the bundled optical fibers with heating, fixing the relative positions of these optical fibers 1 and 2 immediately after the fusing and drawing operation and then accommodating in and fixing to a protective case. If the foregoing difference in the branching ratio is not more than 5%, the difference between the branching ratios determined after the fusing and drawing operation and determined after the coupler is subjected to a thermal shock test is reduced to a level of not more than 2%. Therefore, the coupler does not suffer from any substantial change in properties even after the thermal shock test and thus can practically be used with high reliability.