Network structure has been evolved under leading by Telecommunications Company - network provider -'s vision until in the middle of 1990's when main traffic is for voice. This type of evolution is considerably changed after that time. This is because of activation of Internet which occupies most traffic and to meet the need of Internet user becomes major incentive for network evolution. Namely, user can drive network development. It is noted that Telecommunications Company's revenue got damage from Internet which is data because data traffic doesn't compensate the cost what network provider invested earlier for network building. This is because data traffic has a bursty character, which is completely different from voice traffic. Consequently, network providers have to find efficient network structure that will not only creating revenue but guaranteeing service quality. Optical Internet is considered as best solution to meet both of these and it is absolutely correct. Optical Internet is the combination of IP and optical network with efficiency. Optical network is one of key part for actualization of Optical Internet. Hence, as future network infra, optical network based on optic technology, which provides efficient bandwidth allocation and actively convertible wavelength use using WDM is urgently required.
