Due to the tremendous growth of traffic volume caused by both exponential increase of number of Internet users and continual emergence of new bandwidth demanding applications, high capacity networks are required in order to satisfactorily handle the extremely large amount of traffic. Hence, optical fiber communication is the key technology for the network infrastructure. This book addresses design and analysis of access and core networks targeting important research problems, which need to be tackled for the effective realization of next-generation optical networks. We hope that this book will give the researchers and engineers who work on optical networks an overview of the current trends and contribute to a deeper understanding of problems related to next-generation optical access and wide-area networks, which have tremendous potential to increase network capacity and support the rapidly growing bandwidth demand.