Achievement Award
Research and development of ultra-high-capacity packet transport system
Akira NAKA，Etsushi YAMAZAKI，Shuto YAMAMOTO

Akira NAKA
Etsushi YAMAZAKI
Shuto YAMAMOTO		      
  It is vital to increase the capacity of infrastructure in order to accommodate the explosive increase in traffic demand due to the growth of broadband and mobile services and to do so economically. NTT has conducted research and developed high-capacity and low-power transmission systems that will constitute the new infrastructure.
  In recent years, IP-based services such as Ethernet and VoIP have become the mainstream, and as a consequence the traffic to be distributed in the network of telecommunication carriers has largely shifted from legacy to IP-based services. In order to efficiently accommodate the IP-based traffic, it is essential that the systems can handle IP packets. However, in conventional networks, different equipment for each layer is installed and operated. Therefore, network configuration is complex and management and operation also becomes complicated, which is a problem.
  Dr. Akira Naka and Mr. Shuto Yamamoto developed and disseminated the network concept of applying a layer integrated transport system that allows the expected increased demand from IP-based traffic in the future to be efficiently accommodated by implementing MPLS-TP processing in the transmission system. After they had completed each development process such as the integration and system tests, they constructed the network infrastructure to accommodate the diverse range of services responsible for the explosive traffic growth by installing a layer integration operation system. Because the system made possible remote wavelength switching by a colorless and directionless function.user traffic can be restore quickly and simply in the event of a serious disaster, and it achieved high network reliability along with a 100G-based packet hitless switching function.
  As a means for realizing large capacity, there is a method for improving spectral frequency efficiency by utilizing multi-level encoding. However, as multi-level encoding is susceptible to noise generated in optical fiber propagation, a problem arises in that the transmission distance is limited. Digital coherent optical transmission has solved this problem by correcting the signal using ultra high speed digital signal processing (DSP). The chromatic dispersion equalization by DSP in the system can also reduce unnecessary operational costs such as dispersion measurement and management at system installation.
  The elimination of chromatic dispersion compensation fibers has also contributed to low network latency as well as cost reduction.
  Mr. Etsushi Yamazaki researched and developed the high-performance transmission component of the 100G digital coherent optical transmission system. He quickly commercialized the 100G digital coherent system, bringing it into practical use, leading to subsequent research and development of cutting-edge optical device technology. He verified practical technologies that take into account the actual field environment as well as system maintenance and operation, allowing performance to mature to the point where the practical use of the system became possible.


Figure 1 Configuration of ultra large capacity layer integration transport system and key technology
  As described above, the award winners were responsible for the dissemination of the concept of a layer integrated transport system, and developed low cost and low power [consumption] ultra high capacity systems which consist of an optical cross connect with 8 Tbit/s (100 G x 80 wavelength) and 100 G based packet switches in an actual network infrastructure. The system can provide a range of high performance services and fully satisfy the future demands of network infrastructure.　
References
  1. （1）Optics Express 2011　/　 Fast optical channel recovery in field demonstration of 100-Gbit/s Ethernet over OTN using real-time DSP　/　 E. Yamazaki, S. Yamanaka, Y. Kisaka, T. Nakagawa, K. Murata, E. Yoshida, T. Sakano, M. Tomizawa, Y. Miyamoto, S. Matsuoka, J. Matsui, A. Shibayama, J. Abe, Y. Nakamura, H. Noguchi, K. Fukuchi, H. Onaka, K. Fukumitsu, K. Komaki, O. Takeuchi, Y. Sakamoto, H. Nakashima, T. Mizuochi, K. Kubo, Y. Miyata, H. Nishimoto, S. Hirano, and K. Onohara
  2. （2）OFC 2012　/　 Hybrid 40-Gb/s and 100-Gb/s PDM-QPSK DWDM Transmission Using Real-Time DSP in Field Testbed　/　 S. Yamamoto, T. Inui, H. Kawakami, S. Yamanaka, T. Kawai, T. Ono, K. Mori, M. Suzuki, A. Iwaki, T. Kataoka, M. Fukutoku, T. Nakagawa, T. Sakano, M. Tomizawa, Y. Miyamoto, S. Suzuki, K. Murata, T. Konanigawa, and A. Maeda
  3. （3）SPPCom 2013　/　 Evolution of 100Gb/s digital coherent signal processing moving to metro applications (invited)　/　 E. Yamazaki
  4. （4）IEEE Comm. Magazine　/　100-Gb/s Optical Transport Network and Beyond Employing Digital Signal Processing　/　Etsushi Yamazaki, Masahito Tomizawa, and Yuatka Miyamoto
  5. （5) OECC 2011 　/　PMD Tolerance of 100-Gbit/s Digital Coherent PDM-QPSK in DSF-Installed Field Testbed　/　 S. Yamamoto, S. Yamanaka, A. Matsuura, T. Kobayashi, A. Iwaki, M. Suzuki, T. Inui, T. Sakano, M. Tomizawa, Y. Miyamoto, T. Kotanigawa, and A. Maeda
  6. （6）OECC2010, PD2 (2010)　/　 8-Tb/s(80x127Gb/s) DP-QPSK L-band DWDM Transmission over 457-km Installed DSF Links with EDFA-only amplification　/　 T. Kobayashi, S. Yamanaka, H. Kawakami, S. Yamamoto, A. Sano, H. Kubota, A. Matsuura, E. Yamazaki, M. Ishikawa, K. Ishihara, T. Sakano, E. Yoshida, Y. Miyamoto, M. Tomizawa, and S. Matsuoka
  7. （7）IEICE English publication (2011)　/　PMD Design for High-Speed WDM Backbone Network Systems based on Field PMD Measurements　/　 T. Matsuda, T. Kawasaki, T. Kataoka, A. Naka, and K. Oda
  8. （8）IEICE General Conference (2012)　/　 Performance Evaluation of CD and CDC function of a path switching by OXC　/　T. Seki, F. Hamaoka, T. Matsuda, A. Naka, and K. Oda
 

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