Vol.4 No.2 2011
Research paper : Demonstration of optical communication network for ultra high-definition image transmission (J. Kurumida et al.)−115−Synthesiology - English edition Vol.4 No.2 (2011) estimated to be about 13.4 kW including the optical amplifier. In the demo experiment, the power excluding the server was 1.5 kW with room for expandability to Tb/s. Since the power of some office appliances that could not be isolated from the measured power source circuit was included, the figure was slightly larger than the sum of the ratings of the device groups. However, it was found that basically, the energy saving effect on the value of the power consumption would be more significant as the high-capacity communication data were stuffed. Specifically, when the transmission rate per port becomes100 Gb/s as the silicon photonics optical switch is realized, it is estimated that power efficiency 1,000 times higher may be achieved. Considering the increased communication demand such as for HD video expected in the future, we believe sufficient decrease of power consumption was achieved, as we are able to slow down the increase of power consumption. The optical path network can contribute to the achievement of low power consumption of the communication network.There were several things that became clear for the first time after starting to build the optical path network. Viewing from the OSI modelTerm 8, which is the basis of network connection, the first point is that the cooperation between the layers became complex. This is a complex involvement, starting from the switching occurring at the physical layer to the moment of display as the cache of the browser stores some of the images. We spent time establishing the communication in each optical path, such as in the line that used the media converterTerm 9, because the linkage function corresponding to the converter function behaved differently from the command of the resource management device. In the demo experiment, the issues related to the inter-layer cooperation were solved one by one to bring the system to function. We believe we need an opportunity for more specific demo experiments and mutual connections including the standardization of connection, in order to maximize the potential of the optical path network. Such findings could not have been obtained without the “vertical integration (collaboration)” where the technologies from devices to applications were convened and executed.In the future, it will be necessary to enhance the inter-layer cooperation and to compensate the differences in the wavelength and performances of the transceiver devices in the optical path network. Such R&Ds will be continued as the optical path conditioning technology at the Network Photonics Research Center of AIST. 7 Conclusion:the significance of the demo experimentA new optical communication network that supports the high-definition high-capacity video era was demonstrated through the joint efforts of AIST, five IT related companies, NICT, and NHK Science and Technology Research Laboratories. It was highly significant that through the vertical integration (collaboration) that crossed the organizations, the potential of the new network was demonstrated in surpassing the limitations of the power consumption and communication capacity of the devices that configured the current network. We were able to realize some of the aspects of the new video information service by incorporating the elemental technologies for the newly developed optical communication, and we believe this was an important step in the evolution of the optical communication technology. AcknowledgementsIn conducting the demo experiment we wish to express gratitude to the major contributions of NICT and NHK. We thank the people of the collaborating companies, whose efforts led the demo experiment to success. We also thank the researchers of AIST who were in charge of the elemental technologies, led by Tomohiro Kudoh, group leader of the Information Technology Research Institute, AIST, who worked to install and start up the demo. We would also like to mention that this demo experiment would not have been possible without the guidance and support of Shingo Ichimura, vice-president, AIST and Hiroshi Ishikawa, director, Network Photonics Research Center, AIST. Fig. 6 Communication capacity and power consumption (including estimated values) in the demo configuration144 W1.2 kW (Rating)1.5 kW (Measurement)13.4 kWExperimental value1,000 times more efficientEstimate when silicon photonics optical switch is used entirelyDemo configuration (mixed 1, 10, and 43 Gb/s)Average 9 Gb/sEstimate when IP router is used1000100101.00.1Estimate when 1 Tb/s is used for all portsEstimate when 100 Gb/s is used for all portsDemo configurationTotal power consumption of network (kW)TerminologiesTerm 1. Term 2.Planar light wave circuit (PLC) optical switch: PLC often refers to the planar quartz waveguide. Cross bar switch: the switch with two switching state, the bar and cross states, when considering the connection port with two inputs and two outputs. This electric switching method was originally used in the telephone switchboard before digital switching became common. Recently, it refers to the internal switch element that dynamically selects the route when the data is exchanged between the CPU and the memory within a device.