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Summary form only given. We discuss progress and prospects of network device technologies for ubiquitous communication systems in the 21st century. Broadband and mobile/wireless networks will remove various bottlenecks which block the way to the ubiquitous information society. After a brief overview of the direction toward ubiquitous information technologies, we discuss the technology roadmap with emphasis on broadband photonic network systems as well as access networks. The discussion shows that nano-scale network device technologies will play a key role in the realization of high-performance or low-cost network devices. Nano-scale network devices are based upon various innovative technologies including quantum dots, photonic crystals, and nano-scale controlled interfaces of various emerging materials such as III-nitrides and organic semiconductors.