Vol.4 No.2 2011
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Research paper : Demonstration of optical communication network for ultra high-definition image transmission (J. Kurumida et al.)−109−Synthesiology - English edition Vol.4 No.2 (2011) application software has become available, and a click on the computer (including mobile terminals) connected to the Internet can trigger transmission and reception of high-capacity data. Video information services are provided through the Internet, and the major issue now is how to realize a network while considering the power efficiency to deal with the increased communication traffic. Particularly, the configuration of the optical network consisting of the optical fiber communication technology that is capable of supporting high-capacity data communication is emphasized. The followings are the reasons for the demand based on the social background. Until now, the measures for increased Internet traffic included the parallel installation of communication devices or shifting to equipment with higher communication speed. However, the increased installation of the conventional communication equipment that employed high-speed electric signal processing linearly increased the power consumption as the communication speed increased (power issue). Also, as the connection technology of the optical subscriber lines advanced and optical fibers reached the homes, there has been increasing difficulty in efficiently concentrating the diversified broadband services to the communication node (base station) (communication capacity and network configuration issues). To solve these issues, the important point is how the optical communication lines are developed and configured into a true optical network.The Network Photonics Research Center, AIST proposes a new network called the “optical path network” that directly links the users with the optical path, and engages in R&D to solve the above issues. Particularly, the network where the optical network is switched flexibly to actively maintain the optical path in response to the high-capacity information request is called the “dynamic optical path network”.Specifically, we engage in the technological developments for transmission/reception of the video images, silicon optical path switch, and dispersion compensation, to create an optical network that realizes the broadband service based on the appropriate management and control of each device and device group. Figure 1 shows the conceptual diagram. To utilize the optical switch in the network, a mechanism for controlling the optical switch according to the network application is necessary. That is to say, a mechanism is needed where the mutual connections are made between the HD video server and display, teleconference systems are handled, and these are appropriately managed according to the optical path and storage information. Moreover, vertical integration (collaboration) is essential to introduce the silicon optical path switch and wavelength resource management technologies, and to consolidate and realize the technologies that are developed individually, from device level to application level. These efforts will enable the high-speed data communication without going through multiple electric signal processing, and a network that handles large-capacity information at low power can be configured. In this paper, we mainly describe how the elemental technologies were built up into a system, and how the demonstration experiment was conducted.When the issues manifested in the network are solved by step-by-step approach, it will provide great advantage socially and economically. This may become a communication infrastructure for various services, including the information provision for automobiles and robots (including remote operation), as well as teleconferencing and remote sensing. Such new communication infrastructure will generate new social values in terms of applications software. For example, teleconferencing in which three-dimensional images are shared will decrease the movement of people or business trips, and highly realistic HD video service will decrease the necessity for people to actually go to a certain place. High-speed high-capacity communication infrastructure may provide the basic technology that supports tele-existence, tele-presence, and tele-immersion.3 Scenario of the demonstration experimentIn general, communication network is considered to be a social infrastructure equivalent to electricity, gas, and water. Usually, a new optical fiber network will not be installed from scratch in a city, except in areas where there is no existing network. Therefore, the new network must be implemented step by step by combining the existing and the new technologies. It is necessary to consider the incorporation of the super HD videos into the network for the future. Therefore, we shall discuss the issue from three perspectives. A) To incorporate the distribution of the super HD videos into the demo experiment, we think of a network configured by the coexistence of the super HD video distribution technology (bitrate < 43 Gb/s) and the elemental communication technologies for 1 Gb/s or 10 Gb/s that are already in commercial networks. There are two reasons for doing this. First is to demonstrate that the different communication rates can be handled simultaneously on the network, with focus on the super HD video distribution technology. Second is to demonstrate that it is possible to manage them on the network, to determine the services according to the request, and to actually switch the network for smooth distribution. Next, B) the configuration using the actual field optical fiber is considered. There are also two Fig. 1 Conceptual diagram of the dynamic optical path networkStorage network integrated resource managementSilicon optical path switchWavelength resource managementData storageVideo cameraVideo conference displayHD video serverHD video displayTunable dispersion compensatorTunable dispersion compensatorDynamic optical path networkVertical integrationSilicon photonicsOptical path conditioning technologyNetwork application interface technology

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