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:
Feb. 25, 2003
Filed:
Jun. 09, 1999
Lars Egnell, Saltsjöbaden, SE;
Telefonaktiebolaget LM Ericsson (publ), Stockholm, SE;
Abstract
An optical fiber network of WDM type comprises two fibers which carry light signals propagating in opposite direction and which are arranged in a ring configuration. In the ring, one standby link between two neighboring nodes is used if another link fails. An add and drop node, used in the network only for traffic between neighboring nodes, has band blocking filters connected in respective fibers between a drop coupler and an add coupler. A drop coupler takes out equal shares of the light power to be received through simple switches and bandpass filters in receivers. An add coupler adds new wavelength channels produced in transmitters in the node through multiplexers and simple switches. The switches are used for receiving and transmitting on the wavelength channels in correct directions depending on the location of the inactive link. Thus, the positions of two of the switches have to be changed when the inactive link is one of the two links directly connected to the node. Such a node has a minimun of in-line components, and particulary, a minimum of in-line filtering components.