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Use of Non-Narrowband AWGs for Reducing the Size Requirement of an Electronic Switch

IP.com Disclosure Number: IPCOM000182015D
Publication Date: 2009-Apr-22
Document File: 5 page(s) / 766K

Publishing Venue

The IP.com Prior Art Database

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Prior Art Publishing GmbH: CONTACT

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Use of Non-Narrowband AWGs for Reducing the Size Requirement of an Electronic Switch

Idea: Matthieu Clouqueur, Thomas Engel, Sander Jansen

In the field of optical WDM networks (Wavelength Division Multiplexing), the increasing amount of demands that optical transport networks will have to serve in the next years command that efficient traffic grooming techniques are developed. The goal is to achieve the best possible utilization levels of the high transmission capacity provided by each optical channel (currently up to 40 Gb/sec and soon 100 Gb/sec). With traffic grooming, illustrated in Figure 1, the traffic arriving from multiple directions and/or being locally added at the considered node may be combined and transmitted together within a single wavelength instead of using a separate wavelength for services arriving from each direction.

In order to be aggregated, arriving optical signals are converted to electric signals upon entering the intermediate node. In a next step they are packed together by an electronic switch into payload containers of a higher order before they are encapsulated to an optical signal.

The problem tackled in the following is about defining a new architecture for the grooming node that allows the highest flexibility in assigning wavelengths to the connections that are aggregated at intermediate nodes. The usual trade-off is realized by larger electronic switches providing a larger choice of wavelength paths that may be aggregated at intermediate nodes, but that implicates costs growing rapidly with the number of ports.

Using an electronic switch for performing grooming of client signals inside optical connections, the optical output ports of the electronic switch have to be connected to optical multiplexers that produce the composite optical signals transmitted through the optical fibers. The cabling between the electronic switch and the optical multiplexers can either be done every time a new connection is provisioned, or in advance. The advantage of cabling in advance is that a technician does not need to be sent to the node to install patch cables each time a new connection is provisioned, thus allowing significant operational cost savings. The current pressure imposed on network operators to reduce their operational costs is to send technicians realizing the cabling in remote locations upon each new service provisioning is no longer considered as an option. Therefore, pre-cabling is assumed to be the preferred option.

Current optical multiplexers are designed to expect a given fixed wavelength on each input port as illustrated in Figure 2. That causes the pre-cabling approach to suffer from a serious disadvantage: being, in that case, limited to a very small set of possible wavelength choices when looking for a wavelength for a new connection, because there are only as many waveleng...