Cognitive optical networks enabled by coherent technologies and filterless concepts

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Recent developments in coherent modem performance and digital signal processing (DSP) technologies have stimulated the exploration of novel agile network architectures. The applicant's group has proposed a passive wide area network (WAN) solution, called the filterless optical network, as a cost-effective and reliable alternative to active optical switching network solutions. The proposed optical network architecture is based on the premise that the need for agility can be provided by wavelength tuning at the transmitter and wavelength discrimination by the coherent receiver, in much the same way as agility is achieved in radio networks. Filterless coherent networks essentially offer a passive broadcast medium in which passive non-filtered optical splitters and combiners are used at some nodes for interconnecting the fiber links. The proposed research program builds on both the theoretical research on filterless optical networking and the advanced optical layer test bed developed by the applicant’s group. The program is aimed at proposing novel approaches for coherent optical network design and control, based on filterless and cognitive concepts, and at demonstrating, both theoretically and experimentally, the applicability of these concepts in real-world applications and the impact on cost, performance and energy consumption. In the first phase, the project will explore cognitive optical networking concepts for the design and for the control plane of filterless networks as a potential means to better route traffic and assign resources through quality of transmission, network status and energy consumption awareness. The impairments that are specific to coherent transmission in a branch-tree filterless architecture will be measured and integrated in our filterless design and control plane tools. In the second phase, the project will concentrate on the design of candidate cognitive flexible optical network architectures. A small scale filterless network will be assembled. Specific experiments will be designed for validating these novel networking concepts and evaluating the dynamic performance and benefits of using cognition, in terms of resource utilization, impairment awareness and signal quality evaluation.The originality of the proposed research project lies in the filterless optical networking concept itself, which is looking increasingly like a very serious candidate architecture for future high capacity optical networks, and also because novel cognitive network architectures, enabled by coherent technologies and energy efficient design practices, will be explored from both the theoretical and experimental perspectives, thereby allowing the use of the available bandwidth in new ways, maximizing network flexibility. Some additional innovations are: new design methods and a control plane based on flexible and cognitive optical networking concepts; new design tools and a simulator adapted to coherent networks; cost-effective multicast architectures for content-delivery networks; and new applications, particularly given that filterless networks are likely to exhibit lower line cost and latency, higher reliability, smaller footprint and less node equipment complexity than optical switching networks based on conventional active photonic switching and optical dispersion compensation elements. The proposed research program will be realized in an expected time frame of 5 years. In total, 3 Ph.D. students and 4 Master's students will be involved in the research program.