Optical waveguides – With optical coupler – Plural
Reexamination Certificate
2000-08-01
2004-01-27
Ullah, Akm Enayet (Department: 2874)
Optical waveguides
With optical coupler
Plural
C398S115000
Reexamination Certificate
active
06684005
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to and claims benefit of priority to Swedish Patent Application No. 9903521-4, filed Sep. 27, 1999, entitled “CONNECTION OF AN ADD/DROP NODE,” which is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical communication system, in particular to an add/drop node of an optical WDM (Wavelength Division Multiplexing) network.
2. Discussion of the Background
Optical networks using WDM (Wavelength Division Multiplexing) technology are become more and more prevalent. These networks utilize a number of add/drop nodes that are interconnected; as the number of nodes increases, the complexity of the connections also increases. A simple approach is needed to connect these add/drop nodes to the network. In addition, upgrades to the add/drop nodes should likewise be simple. For example, when the capabilities of an existing add/drop node is expanded to operate at another wavelength band, the work that is required to upgrade the add/drop node should be minimized.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an add/drop node for an optical WDM-network that has a simple mechanism to connect the node to the circulating fiber paths of the network.
According to one aspect of the invention, an add/drop node used in an optical network having two fiber paths for carrying light corresponding to a plurality of channels in opposite directions comprises a pair of add/drop modules that correspond to one of the plurality of channels. Each of the add/drop modules includes an add device that is configured to add light to one of the fiber paths, and a drop device configured to deflect a portion of the light from another one of the fibers paths. The pair of add/drop modules have identical construction. The above arrangement advantageously provides a simple approach for connecting the components of an add/drop node.
According to another aspect of the invention, an optical communication system comprises a plurality of fiber paths that carry optical signals corresponding to a plurality of channels in opposite directions. A plurality of add/drop nodes are coupled to the fiber paths. Each of the add/drop nodes includes a pair of add/drop modules that corresponds to one of the plurality of channels. Further, each of the add/drop modules includes an add device that is configured to add light to one of the fiber paths, and a drop device that is configured to deflect a portion of the light from another one of the fibers paths. The pair of add/drop modules have identical construction. The above approach simplifies scaling of the add/drop node.
According to yet another aspect of the invention, an add/drop node used in an optical network having two fiber paths for carrying light corresponding to a plurality of channels in opposite directions comprises a pair of add/drop modules that correspond to one of the plurality of channels. Each of the add/drop modules includes a means for adding light to one of the fiber paths, and a means for deflecting a portion of the light from another one of the fibers paths. The pair of add/drop modules have identical construction. The above arrangement advantageously permits ease of expanding the capabilities of the add/drop node.
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Zhao, Y. et al. “A novel bi-directional add/drop module for single fiber bi-directional self-healing wavelength division multiplexed ring networks.” In: Optical Fiber Communications Conference, 1999. vol. 1, Feb. 21-26, 1999, pp. 183-185.
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Bonnedal Dag
Egnell Lars
Hulten Ola
Johansson Bengt
Linden Fredrik
Cisco Systems (Sweden) Aktiebolag
Ritter Lang & Kaplan LLP
Ullah Akm Enayet
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