Semi-filterless optical network: a cost-efficient passive wide area network solution with effective resource utilization

By utilizing advanced optical coherent transmission and electrical compensation technologies, two novel passive wide area network (WAN) solutions, filterless and semi-filterless optical networks, are able to eliminate the usage of the expensive active photonic reconfigurable components by interconnecting the nodes with passive optical power splitters/combiners and using tunable transceivers. Therefore, they have a potential to be more cost-effective and energy-efficient as well as more reliable than the networks based on active optical switching. In comparison with the filterless approach, the semi-filterless optical network can improve resource utilization by introducing passive wavelength filters at some selected nodes. This paper proposes a semi-filterless optical network design tool for filter placement and wavelength assignment and validates it on a number of network topologies. Performance evaluation confirm that the proper design of semi-filterless optical networks can offer significant reduction of the number of wavelengths needed to support a certain traffic demand compared to filterless networks while keeping all the advantages of the passive WAN solution.