Master Thesis - 2010

High speed and large capacity backbone network is required for high quality multimedia services. For the next generation networks, all optical WDM networks have been expected as one of promising solutions. In WDM networks, physical impairments make a serious impact on the performance of networks. Therefore, physical impairments are becoming one of main issues in researches for WDM networks. In general, WDM networks have many fibers between nodes. The effects of physical impairments depend on allocation of used wavelengths and equipped fibers. Thus, it is hopeful that selecting appropriate wavelengths and fibers can mitigate the effects of physical impairments.

In this thesis, physical impairments based path set-up method is proposed. The proposed method pays attention to Four Wave Mixing (FWM) as one of representative physical impairments. The proposed method can mitigate the effects of FWM on requesting path and existing connections. In particular, concerning wavelength assignment method, adaptive wavelength lists considering the number of transmission hops is proposed. Concerning fiber selection method, the effects of FWM on fibers which are along the requesting path, are approximately calculated by using simple formula. After that, fibers are selected in order to alleviate the effects of FWM on existing connections.

Finally, the effectiveness of the proposed method is evaluated through simulation experiments. In particular, the proposed method can reduce both call blocking probability and unsatisfied FWM probability for existing connections more than 90\% when traffic load is low.