June 2017 Vol. 15 No. 6

Feature Articles: State-of-the-art Space Division Multiplexing Technologies for Future High-capacity Optical Transport Networks

• Space Division Multiplexing Optical Transmission Technology to Support the Evolution of High-capacity Optical Transport Networks

  

  Abstract
  This article describes high-capacity space division multiplexing (SDM) optical transmission technology to support the evolution of broadband networks. A new spatial degree of freedom is introduced in optical transmission systems, optical node equipment, and optical fibers to overcome the physical limits of today’s single-mode fiber based systems. Future SDM-based optical networks will achieve high capacities of over 1 Pbit/s in a single strand of fiber, a 100-fold increase in capacity, and node throughputs of more than 10 Pbit/s.

• Dense Space Division Multiplexing (DSDM) Long Distance Optical Fiber Transmission Technology

  

  Abstract
  Multi-core and multi-mode space division multiplexing (SDM) technology is being studied as an optical transmission technology targeted for the next generation high-capacity optical communication network. In this article, we describe the latest trends in optical transmission using SDM technology. We introduce the world’s most advanced ultra-high-capacity long distance optical transmission realized by dense space division multiplexing (DSDM) with a spatial multiplicity above 30, which was achieved in joint global academic and industrial research collaborations.

• Dense Space Division Multiplexing (DSDM) Photonic-node Platform Technology

  

  Abstract
  Optical infrastructure networks transporting high-volume traffic have been built using photonic node technologies such as optical signal transmission, optical signal wavelength multiplexing and demultiplexing, and reconfigurable optical add/drop multiplexers. This article gives an overview of photonic nodes using dense space division multiplexing technology and their potential for implementing high-capacity optical networks.

• Optical Amplification Technologies for Space Division Multiplexing

  

  Abstract
  Technologies that enable simultaneous optical amplification of spatially multiplexed optical signals are essential for a long-haul space division multiplexing (SDM) transmission system that employs a multi-core fiber and/or few-mode fiber. This article introduces optical amplification technologies that make it possible to construct a multi-core erbium-doped fiber amplifier (EDFA) and a few-mode EDFA for SDM transmission.

• Research and Development of Next Generation Optical Fiber Using Multiple Spatial Channels

  

  Abstract
  The capacity of conventional single-mode fiber (SMF) that is widely used in the existing optical communication network is expected to be limited to around 100 Tbit/s. Therefore, next generation optical fiber such as multi-core and/or multi-mode fiber has been investigated in order to overcome the limited capacity of SMF and to utilize multiple spatial channels to realize space division multiplexing (SDM). We introduce in this article the recent progress achieved in SDM fiber.

• Multi-core Fiber Connector Technology for Low-loss Physical-contact Connection

  

  Abstract
  The NTT laboratories have been researching and developing connection technology for multi-core fiber, which is expected to be the transmission medium in future high-capacity transmission systems. In this article, we introduce a multi-core fiber connector that achieves physical-contact connection with low loss, and a pluggable fan-in/fan-out device connecting multi-core fiber and single-core fiber.

Global Standardization Activities

• Activity Report of ITU-T Focus Group on IMT-2020

  

  Abstract
  In 2015, the ITU-T (International Telecommunication Union - Telecommunication Standardization Sector) established the Focus Group on IMT (International Mobile Telecommunication)-2020 (FG IMT-2020) to study the non-radio part of IMT-2020. The FG worked until December 2016 and produced key concepts such as the network slice and network softwarization components constituting the IMT-2020 system. This article presents the activities of FG IMT-2020.

Practical Field Information about Telecommunication Technologies

• Case Studies of Wireless LAN Problems

  

  Abstract
  This article describes cases studies of problems occurring in wireless LANs (local area networks). This is the fortieth article in a series on telecommunication technologies. This contribution is from the EMC Engineering Group, Technical Assistance and Support Center, Maintenance and Service Operations Department, Network Business Headquarters, NTT EAST.

Information

• Event Report: Science Plaza 2016 at NTT Basic Research Laboratories

  

  Abstract
  Science Plaza 2016, an open-house event hosted by NTT Basic Research Laboratories, was held at NTT Atsugi R&D Center on November 23, 2016. Under the banner “Frontier Science: Open Door to the Future,” Science Plaza was aimed at disseminating our latest research accomplishments to various groups of people inside and outside of NTT as well as gathering diverse opinions. This event was held jointly with NTT Device Innovation Center, NTT Device Technology Laboratories, and NTT Communication Science Laboratories.

Short Reports

• One-petabit-per-second Fiber Transmission over a Record Distance of 200 km―Paving the Way to Realizing 1000-km Inline Optical Amplified Transmission Systems within C Band Only

External Awards/Papers Published in Technical Journals and Conference Proceedings

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