August 2011 Vol. 9 No. 8

Front-line Researchers

• Yutaka Miyamoto, Senior Distinguished Researcher, NTT Network Innovation Laboratories

  

  Toward Well-timed Application of Advanced Technology

  Abstract
  Ultrahigh-capacity digital coherent optical transmission technology for communication networks of the broadband era builds upon past results and successful implementations in the optical communications field. With this technology, Senior Distinguished Researcher Yutaka Miyamoto aims to achieve transmission in excess of 100 Tbit/s over one strand of optical fiber. We asked him about his past experiences in this field and the key transitions that he has seen in optical communications.

Feature Articles: Ultrahigh-speed Ultrahigh-capacity Optical Transport Network

• Ultrahigh-speed Ultrahigh-capacity Transport Network Technology for Cost-effective Core and Metro Networks

  

  Abstract
  This article introduces cost-effective highly functional ultrahigh-speed ultrahigh-capacity optical transport network technologies that use optical paths to provide safe and secure diverse services cost-effectively.

• Ultrahigh-capacity Digital Coherent Optical Transmission Technology

  

  Abstract
  In this article, we introduce the current progress in ultrahigh-capacity digital coherent optical transmission technology that will support future broadband networks. It enables great improvements in optical transmission performance through the use of ultrahigh-speed digital signal processing and will lead to capacities exceeding 10 Tbit/s per optical fiber.

• Photonic Network Node Technology for Transparent Path Accommodation

  

  Abstract
  In this article, we introduce research and development trends related to optical-electrical hybrid nodes. Meeting the demands for higher channel capacities, by for example wavelength division multiplexing at 100 Gbit/s per wavelength, will require not only optical switching of optical paths at photonic nodes, but also sub-lambda (electrical path) technology for multiplexing/demultiplexing and switching 1–10 Gbit/s medium-sized electrical paths.

• Highly Efficient Photonic Networking Technology

  

  Abstract
  This article introduces a networking management control technology that achieves highly efficient photonic networking by having λ paths (wavelength paths) and sub λ paths function cooperatively to increase the efficiency of user traffic accommodation.

• International Standardization and Implementation Technologies for Optical Transport Networks

  

  Abstract
  This article introduces recent trends in international standardization related to optical transport networks and NTT's standardization activities. We also present standardization activities related to optical transmission with 100 Gbit/s per wavelength, which have drawn attention recently. Furthermore, as an example of applying the standardization results up to now to devices, we introduce two types of large-scale integrated circuits for optical transmission equipment.

• Innovative Future Optical Transport Network Technologies

  

  Abstract
  This article introduces two initiatives by NTT–innovative optical transmission technology and elastic optical path networks–as ways to achieve rapid enhancement of the optical network in order to meet the demand for a thousand-fold increase in information volume and to fully utilize the potential of existing optical fiber.

Feature Articles: Latest Trends of Multimedia Broadcasting Technologies for Mobile Terminals

• Service and Technology Overview of Multimedia Broadcasting for Mobile Terminals

  

  Abstract
  This article briefly explains the multimedia broadcasting service for mobile terminals planned to start in Japan in spring 2012, after the frequency band currently used for terrestrial analog broadcasting became available in July 2011, and the technology that will support it. This service is based on the ISDB-Tmm (integrated services digital broadcasting, terrestrial mobile multimedia) system. Part of the system will use technology from NTT's research and development.

• Metadata Technologies in Multimedia Broadcasting for Mobile Terminals

  

  Abstract
  In this article, we explain metadata technologies with a focus on the use of metadata in multimedia broadcasting, which is a new type of broadcasting media service for mobile terminals that uses the new technical standard for broadcasting, ISDB-Tmm (integrated services digital broadcasting, terrestrial mobile multimedia), and offers both realtime and storage-based broadcasting services.

• Access Control in Multimedia Broadcasting for Mobile Terminals

  

  Abstract
  This article explains access control technology and content protection technology that will serve as content security measures when multimedia broadcasting is provided as a pay service. High-quality audio-visual streaming services based on ISDB-Tmm (integrated services digital broadcasting, terrestrial mobile multimedia) are planned for 2012. They are expected to include realtime services and storage-based services.

• Storage-based Broadcasting in Multimedia Broadcasting for Mobile Terminals

  

  Abstract
  This article outlines the technology behind storage-based broadcasting, which is provided in addition to realtime broadcasting in multimedia broadcasting for mobile terminals. It can deliver large files of multimedia content to users in an efficient manner via broadcast systems.

Regular Articles

• Ultralow-energy All-optical Switches Based on Photonic Crystal Nanocavities

  

  Abstract
  Photonic crystal cavities having a wavelength-sized volume exhibit a strong light-matter interaction, which makes possible all-optical switches operating with ultralow energy consumption. Using the combination of an extremely small photonic crystal nanocavity and strong carrier-induced nonlinearity in InGaAsP, we have successfully demonstrated low-energy switching in the attojoule range for the first time. This switching energy is more than two orders of magnitude lower than that of previously reported optical switches. The ultrasmall cavity also contributes to fast carrier diffusion and hence a fast switching response of 20 ps at minimum. These all-optical switches with their small size and low-energy, fast-response operation may open up the possibility of a dense photonic network on a chip.

• Hyper Multi-point Satellite Communications System and Field Trial Results

  

  Abstract
  This article presents our newly developed hyper multi-point data-gathering satellite communications system for enhancing the frequency utilization of satellite transponders and the results of field trials for evaluating its feasibility using the Japanese Engineering Test Satellite VIII. We have developed a prototype system that can collect various types of sensor data with high frequency utilization efficiency from a large number of data-sensing stations scattered over a wide area in a unified manner. The experimental results show that this system successfully collected sensor data having different characteristics such as frequency and data size simultaneously and efficiently.

• Polarization-tracking-free Satellite Communications System Using Adaptive Polarization Division Multiplexing

  

  Abstract
  We have developed a novel Ku-band broadband mobile satellite communications system called the adaptive polarization division multiplexing (APDM) system. It eliminates the need for a polarization-tracking device in earth stations and improves the spectrum utilization efficiency. This article overviews the concept of the APDM system and describes the technologies that make the system possible. Experiments have shown that the system can provide practical polarization-tracking-free Ku-band broadband mobile satellite communications.

• UMS: Software to Automate Operators' Actions

  

  Abstract
  We have developed a unified management support system (UMS), which is software that reduces the workload on operators and operating costs by automating operations. UMS makes it extremely easy for an operator who is not a computer expert to record and replay actions taken on systems. Since most modern systems are extremely complex, UMS can improve system operation efficiency. This article describes the features and technologies of UMS and gives usage examples.

Global Standardization Activities

• ITU-T Kaleidoscope Academic Conference 2010––Participation Report

  

  Abstract
  Kaleidoscope 2010, the third academic conference hosted by ITU-T (International Telecommunication Union, Telecommunication Standardization Sector), took place in Pune, India, on December 13–15, 2010. Its theme was "Beyond the Internet?––Innovations for future networks and services". Selected papers contributed from the world's universities, industries, and academic institutions, including NTT, were presented and discussed.

Practical Field Information about Telecommunication Technologies

• Corrosion Fractures in Wire Grips

  

  Abstract
  This article describes corrosion fractures in wire grips and introduces countermeasures to this problem. It is the sixth in a bimonthly series on the theme of practical field information about telecommunication technologies. This month's contribution is from the Materials Engineering Group, Technical Assistance and Support Center, Maintenance and Service Operation Department, Network Business Headquarters.

External Awards/Papers Published in Technical Journals and Conference Proceedings

• External Awards/Papers Published in Technical Journals and Conference Proceedings