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:
Mar. 22, 1994
Filed:
Apr. 30, 1993
Rolf Heidemann, Tamm, DE;
Jurgen Otterbach, Leonberg, DE;
Alcatel SEL A.G., Stuttgart, DE;
Abstract
Prior art fiber-optic amplifiers which are used in a fiber-optic link to amplify the light signals to be transmitted have the disadvantage that the semiconductor lasers employed as pump lasers are highly sensitive to feedback, so that the stability of the light-signal transmission is impaired by pump light reflected back into the pump lasers. According to the invention, the operating current for such pump lasers (4) contains a noise current, so that the pump laser emits its pump light in many modes, which makes it insensitive to feedback. To prevent the noise component of the pump light which is caused by the noise current from affecting the amplification of the light signals to be transmitted, the noise current is filtered in such a way that its spectral components have frequencies which lie above the reciprocal lifetime of that energy level of the active laser medium which causes the amplification of the light signals.