Optimal design of optical WDM networks

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Optical networks are widely used in backbone computer networks. Due to the rapid increase of the totalvolume of internet traffic, it is very important to reduce the capital cost of setting up new networks and the operating cost of the networks by making optimum use of network resources. This investigation will use modern Operations Research techniques and develop algorithms that will a) reduce the cost of deploying optical networks, b) improve the efficient use of the network in handling the requests from users for data communication, and c) improve the resiliency of such networks. One problem with all-optical wavelength division multiplexed networks is the fact that the quality of optical signals degrade when the fiber length increases. It has become important, in the next generation networks, to develop methods to recover signal quality in a cost-effective manner. The cost of deploying an optical network is significantly reduced if an efficient strategy is used to minimize the number of "regenerating" nodes which can restore the quality of optical signals. The efficiency of a WDM network is improved if more requests for data communication can be handled with existing resources. Using advanced Operations Research tools, our research will improve the state of the art, both in terms of reducing the number of regenerating nodes used and in improving the efficiency of the network. Each optical fiber in such a network carries an enormous amount of data, so that the failure of a single fiber in a network, even for short durations, has significant economic impact. We will develop schemes that are relatively inexpensive and still guarantee fault-tolerant operations. Orthogonal Frequency-Division Multiplexing (OFDM) is being investigated to make more efficient use of the network bandwidth. The proposed research will develop algorithms to enable more requests for data communication to be considered.Three problems will be considered - i) if all the requests for data communication are known in advance how to handle them in the most efficient manner, ii) if the requests are to be handled dynamically how to handle them best and iii) how to incorporate fault tolerance in an OFDM network.