Vol.4 No.2 2011

Research paper : Demonstration of optical communication network for ultra high-definition image transmission (J. Kurumida et al.)−112−Synthesiology - English edition Vol.4 No.2 (2011) optical amplifier method that can be used as the wavelength conversion technology, but HNLF was employed since the non-dependency on the modulation format would be useful in the future. In the demonstration, the wavelength conversion from the C-band to the L-bandTerm 5 was incorporated. 4.3.7 High-speed autonomous-control optical tunable dispersion compensator (Furukawa Electric and AIST)Furukawa Electric Co., Ltd. and AIST proposed and demonstrated the tunable dispersion compensator that combines the wavelength dependent dispersion medium and the wavelength conversion by parametric process, called the optical parametric tunable dispersion compensator (P-TDC)[11]. By using the four wavelength mixing (FWM) of the HNLF[12] that has low dispersion slope with the principle of phase maintaining wavelength conversion, we achieved a gridless broadband function surpassing 1 THz that could not be achieved by the conventional tunable dispersion compensation technology. Projecting that the optical path will be dynamically switched in the future optical network, the high-speed tuning response of microsecond order is realized[13]. For the transmission experiment, this technology was applied to the field fiber of 105 km line through which the Super Hi-Vision signals are transmitted at 43 Gb/s. 4.4 Terminal equipment4.4.1 SHV transceivers (NHK)The Japan Broadcasting Association (Nippon Hoso Kyokai = NHK) leads the development of the device that enables the transmission and reception of uncompressed Super Hi-Vision (SHV) in the 24 Gb/s dual green method by the 43 Gb/s optical signal[14]. The network was configured via the 105 km field fiber. The long distance transmission was achieved by the high-speed autonomous control tunable dispersion compensation technology described in section 4.3.7. 4.4.2 Content archive server, delivery server, and displayThe content archive server is the computer in which the image contents are stored, and this archive/delivery server functions by the command (section 4.1.1) of the network storage resource manager of the optical path network. The display was configured by devices that were readily available using the SHV monitor. 4.5 ContentsThe contents we used were the SHV videos (NHK) and Hi-Vision videos. The former was SHV videos with 33 million pixels/frame, and these were about four times larger both horizontally and vertically than the regular Hi-Vision videos. With the cooperation of NHK, two SHV videos were set in the demonstration system, ready to be transmitted.For the regular Hi-Vision (or HD), we purchased a general-use HD video camera and shot our own contents. The videos were set in the delivery server. 5 Demonstration experimentImportance of demo experiment for communication technologies is basically to demonstrate that it is possible to deliver information from point A to point B, including the switching technology. The important factors of the experiment include the site where the transmitting/receiving terminals are located, construction of the experimental system based on the plan, and then to execute the transmission and switching of the actual video information. Considering these factors, we configured the demo experiment as shown in Fig. 3. The elemental technologies described in chapter 4 are also shown in the diagram. In this chapter, we describe how the elemental technologies described in the previous chapter were incorporated into the experiment.Figure 3 shows the configuration where the two networks are mutually connected. The blue area on the left side is the NICT’s Optical Packet and Circuit Integrated Network, and the green area on the right is the AIST’s optical path network. NHK’s SHV transceiver technology is set in the middle. This topologyTerm 7 was the result of discussing the points of mutual connection. The blue connection line indicates the optical fiber. The switch request method of the networks was predetermined. The network in the black dotted line on the right of the diagram were located entirely in Akihabara, and the line went to NICT’s Optical Packet and Circuit Integrated Network via Otemachi, Koganei and then back to Otemachi, with connecting points NICT-EAST and NICT-WEST. After the control environment of the network was set up, and the stage progressed to the video distribution experiment (subchapter 5.2).5.1 Site of the experiment and construction of the experimental systemAlthough it seemed that the demo experiment could be executed anywhere, we decided the site as we narrowed down the available filed optical fiber. Since it was necessary to use the R&D testbed network (JGN2plus) as mentioned in subchapter 4.2, we considered the appropriate terminal station. The east terminal of the JGN2plus was located in Otemachi (Chiyoda-ku, Tokyo). Therefore, we reached the conclusion that we could create the network relatively easily by connecting with the AIST Akihabara (Soto-Kanda, Chiyoda-ku Tokyo) through the commercial optical fiber. Although it was also possible to connect to the AIST headquarters in Tsukuba, Ibaraki, the more convenient AIST Akihabara was selected since there was no extension of the R&D testbed network to Tsukuba, and we wanted to conduct the demo experiment during the symposium. The distance between Otemachi and Akihabara was 1~2 km by line of sight, but the optical fiber actually used was 9.8 km. This was because the usable laid optical fiber traveled up to a certain floor of the building and then went into the underground common utility hole. After the optical fiber line between Otemachi and Akihabara was


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