Vol.4 No.2 2011

Research paper : Demonstration of optical communication network for ultra high-definition image transmission (J. Kurumida et al.)−117−Synthesiology - English edition Vol.4 No.2 (2011) Shu NamikiLeader, Optical Signal Processing System Research Team, Network Photonics Research Center, AIST. He received the master’s degree from the Graduate School of Science and Engineering, Waseda University in 1988. Joined the Furukawa Electric Co., Ltd. in 1988. Engaged in research and product development of the semiconductor optical device, mode-locking laser, light amplifier, nonlinear fiber optics, and optical transmission. Visiting researcher at Massachusetts Institute of Technology, USA from 1994-1997. Joined AIST in 2005. Has coauthored over 200 publications, and served as member of several international conference programs, as well as member of International Organization for Standardization/International Electrotechnical Commission (ISO/IEC). Vice-chairman of the Editorial Board, IEICE Transaction B (Communications) of the Institute of Electronics, Information and Communication Engineers. Associate editor, Optics Express, Optical Society of America from 2005. Currently, advisory editor, Optics Express and deputy chief editor of IEICE Society. Doctor of Science. Fellow of the Optical Society of America. In this paper, considered the direction of the demo experiment and the outline of the elemental technology to be combined.Discussions with Reviewers1 Background of the paperComment (Naoto Kobayashi, Center for Research Strategy, Waseda University)The main theme of this paper is that a demonstration experiment was conducted to realize the dynamic optical path network. Yet I think there is lack of explanation on what is a dynamic optical path network, and how it can realize low-power optical communication (also why that’s not possible with packet communication). I think you should describe these to help the understanding of readers outside of the field. Answer (Junya Kurumida)I think you indicated an important point in the description. To clarify the optical path network, I added the following section in paragraph of chapter 2: “… a new network called the ‘optical path network’ that directly links the users with 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’.” Also, as the reason for the realization of low-power optical communication, I added in chapter 2: “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.”To make the point clear for the readers, I added the following sentence in chapter 1 and the issues will be discussed in the following chapter: “On the other hand, there is a major problem in the sustainable development of such advanced communication service. It will be explained in the following chapter.”Comment (Hiroshi Tateishi, New Energy and Industrial Technology Development Organization)I understand that the point of this paper is the demonstration of the low power consumption by using only optical components in the high-capacity network, the seamless mutual connection technology of heterogeneous networks and the implementation of the super high-capacity content distribution based on these technologies, in one model experiment. However, I cannot understand where the breakthrough point was, or how things were solved. Please organize and present the background and the outline of the research in an understandable manner. The press release* for this experiment on the AIST website is much clearer. After doing this, please describe the important points from the perspective of R&D. You have described what you have done in detail, but you did not explain “why they had to be done” or “what were the problems and how they were solved”. Please consider these and write with a stance that you are trying to get some third-party people to understand.Answer (Junya Kurumida)Thank you very much for your important indication. I added the segment “…the new network technology that overcomes the limitations of power consumption and communication capacity of the devices that configured the current network” in the outline, and added the sentence “With the background of increased demand in communication mainly for the Internet, the energy savings in optical communication is an immediate issue”. in the beginning of “1 Introduction” to clarify the background and outline of the research.To solidify the perspective from R&D, I added the description about establishing the 43 Gb/s path communication, that is the highlight of this demo and is the fastest optical modulation signal at 105 km transmission distance, to the “5.2 Video distribution experiment”. The three viewpoints of the scenario explained in chapter 3 were organized as A, B and C and were explained correspondingly in chapter 6.*http://www.aist.go.jp/aist_j/press_release/pr2010/pr20100824_2/pr20100824_2.html2 Demo experiment system and its significanceComment (Naoto Kobayashi)I think the elemental technologies are explained well. However, the part on the achievement of the demo experiment system and the significance of the successful research are expressed weakly, and the significance of this major accomplishment may not be communicated to the readers. Therefore I think you should do the following:1. You should clearly show how the scenario shown in chapter 3 was realized in the demo experiment, as the result shown in chapter 3, “(1) to configure a network with coexisting communication elemental technologies such as 1 Gb/s and 10 Gb/s, (2) to configure the network using the already laid optical fiber, and (3) to work on these further to achieve low power consumption”.2. Since it is highly significant that the elemental technologies were integrated to create a system, I think you should tell the difficulties of the integration and how you were able to overcome them in more detail.Comment (Hiroshi Tateishi)In subchapter 5.1, you describe in detail the distance of the intermediate optical fiber, but you do not explain what that length means for the experiment, so I don’t know how to interpret the information. Do you wish to say that in practice, implementing this distance is sufficient for the purpose of demonstration, or did it simply end up this way and there’s not much technological meaning? Whichever the reason, when you give specific figures, the readers become curious about the meaning behind them.Answer (Junya Kurumida)Thank you very much for indicating the improvement points for the paper.


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