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Optical Networks
Optical Network Technology
Optical communication technology is widely utilized for high capacity backbone network connecting large cities, and optical access networks that directly relates to customer services such as business and residential. Green platform research laboratories have been working on the optical communication technology research from early stage of this field, and made major breakthroughs as a leader in the world against high speed optical communication problems.
With a rapid growth of cloud computing and a wide spread of smartphones, network traffic is still continuously increasing explosively. Optical network as an important social network infrastructure is required to accommodate this explosive traffic demands without consuming too much energy and cost. To satisfy this requirement, the optical network should provide not only high capacity and long distance but also an immediate end-to-end connection after optical signal path switching. We are focusing on developing this “adaptive optical network” technology.
One of the main research items of the adaptive optical network is a cutting-edge R&D of optical modulation, multiplexing and transmission technology that carries signal beyond 100G bps. Among many items in this area, we are focusing on research and development of digital coherent optical transmission. The digital coherent technology enables optimum signal reception automatically when the signal distortion varies with a change of optical path. The optimum reception is attained by using digital signal processing of signal waveform, thus received information error is minimized. Our main activity is to develop effective processing algorithm against severe distortion which occurs in a long distance fiber transmission line.
We are also working on optical switching technology. The optical switching will enable signal path alteration without converting to electrical signal. Current optical network employs power inefficient electrical switching in which the optical signal is frequently converted to electrical then it is recovered to optical signal again after switching. Those signal conversions are useless if all the transmission data passes through the switching node. The optical switching is effective in such case but switching device development and wavelength conversion are current issues. We are working on a technology development to solve this problem for enabling energy efficient optical network.
