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September 1, 2021

Nippon Telegraph and Telephone Corporation

"100km VAD Single-Mode Optical Fiber" that contributed to the realization of the optical communication era
Registered in the National Museum of Nature and Science
[MIRAI Technology Heritage]

Nippon Telegraph and Telephone Corporation (Headquarters: Chiyoda-ku, Tokyo, President: Jun Sawada, hereinafter "NTT") that its"100km VAD Single-Mode Optical Fiber," a star entry in "NTT History Center of Technologies," has as, of September 1st 2021, has been designated by National Museum of Nature and Science as an "Essential Historical Materials for Science and Technology (short form: MIRAI Technology Heritage)."*1 As the first technology to demonstrate the validity of the industrial-scale production of long, low-loss single-mode optical fiber, the vapor-phase axial deposition (VAD) method*2 is of critical importance in terms of realizing the optical communication era.
※ Registration certificate and commemorative plaque award ceremony will be held at the National Science Museum on September 14, 2021.

1.Details of 100km VAD Single-Mode Optical Fiber

Current optical fibers that support most optical fiber communication, have a two-layer structure consisting of a core in the center through, which light passes, surrounded by a cladding.
 The most common approach to producing optical fiber starts with quartz glass as the raw material.
 Very fine particles of core and cladding are produced by flame hydrolysis. A columnar porous two-layer structure (base material) is formed continuously and fused at high temperature to make it transparent.
 Optical fiber is created by heating and stretching this base material.
 In the early 1970s, NTT began researching optical fiber manufacturing technology, as research and development activities began around the world in the latter half of the 1960s had shown the feasibility of glass optical fibers as a transmission medium for communications.
 Concurrently with the MCVD method and OVD method*3 devised in the United States, NTT launched a joint research project with Furukawa Electric Co., Ltd., Sumitomo Electric Industries, Ltd., and Fujikura Ltd. to improve the MCVD method so that is was suitable for mass production and unique to Japan.
 In 1977, at the international conference "IOOC'77"*4, the VAD method was announced as a truly innovative optical fiber manufacturing method unique to Japan with excellent mass productivity; it was evaluated very highly.
 Further research and development activities conducted after 1977 yielded the establishment of an optical fiber mass production process based on the VAD method.
 The result was a practical manufacturing method for ultra-low loss optical fiber*5.
 The VAD method has several additional benefits such as easy enhancement and low loss of the optical fiber base material.
 It has become possible to manufacture optical fibers with extremely low transmission loss in long continuous lengths of 100 km or more without connection or seams.
 VAD has greatly contributed to the mass production of optical fibers with the attendant economy of scale.

100km long VAD single mode optical fiber 100km long VAD single mode optical fiber

Reference: What is NTT History Center of Technologies?

The NTT HISTORY CENTER OF TECHNOLOGIES exhibits in timeline fashion a collection of historical assets of the NTT group, accumulated as the result of the group's development of telecommunications technologies with particular focus on the half-century since the foundation of the Nippon Telegraph and Telephone Public Corporation.
 It introduces more than 1,500 technical historical materials in two parts: "Tracing the History" and "Exploring the technologies".
 So far, the following technical historical materials have been registered with the "MIRAI technology Heritage".
 The NTT History Center of Technologies is open to the public for free visits. For details, please check the NTT History Center of Technologies website(http://www.hct.ecl.ntt.co.jp/Open other window).

  • Registered in 2010 (No. 00060) (1) Maritime Mobile Telephone System NS-1 JAA-333
    (2) Wireless Telephones (Wireless Telephones introduced at the World Exposition held in Osaka in 1970.)
    (3) Car Telephone TZ803A

  • Registered in 2011 (No. 00084) (1) 4 GHz Band Microwave Traveling-Wave Tube
  • Registered in 2011 (No. 00087) (1) Pocket Bell B Type RC11 2 variants
  • Registered in 2012 (No. 00105) (1) D10 Electronic Switching System
  • Registered in 2014 (No. 00142) (1) Radio pager transmitting equipment (Transmitter TC-11, Transmitter TC-15, Encoder CE-15)
  • Registered in 2016 (No. 00224) (1) D60 Digital Switching System
  • Registered in 2017 (No. 00232) (1) C400 Switching System
  • Registered in 2018 (No. 00250) (1) Magneto Switching System
  • Registered in 2019 (No. 00274) (1) Apparatus for Production of Optical Fiber Base Material Using the VAD Method
  • Registered in 2019 (No. 00275) (1) F-32M-1 Terminal Repeater Equipment

Glossary / Supplement

  1. Essential Historical Materials for Science and Technology (short form: MIRAI technology Heritage): From 2008, the National Museum of Nature and Science has been publicizing the important achievements in the history of science and technology development. With the twin goals of "History of Science and Technology Materials" and "National Life," which are important for passing on to the next generation, the economy, society, it offers a registration system for Essential Historical Materials for Science and Technology (short form: MIRAI technology Heritage) in order to preserve and promulgate "science and technology history materials that have significantly influenced the state of culture"
  2. VAD(Vapor-phase Axial Deposition):
    Advanced method for manufacturing the glass preforms (base material) that are the basis of optical fiber
  3. MCVD(Modified Chemical Vapor Deposition)・OVD(Outside Vapor Deposition)
  4. IOOC'77: International Conference on Optical IC / Fiber held in Tokyo in 1977
    (International Conference on Integrated Optics and Optical Fiber Communication, 1977)
  5. Ultra low loss:As of 1980, succeeded in developing single-mode optical fiber with ultra-low loss of 0.2 dB / km at 1.55 μm by the VAD method.

Contact Information

Nippon Telegraph and Telephone Corporation
Information Network Laboratory Group
Planning Department, Public Relations Section
E-mail:inlg-pr-pb-ml@hco.ntt.co.jp

Information is current as of the date of issue of the individual press release.
Please be advised that information may be outdated after that point.