Milestones:Invention and development of vapor-phase axial deposition (VAD) method for mass production of high-quality optical fiber for telecommunication
Vapor-phase Axial Deposition Method for Mass Production of High-quality Optical Fiber, 1977-1983
In 1977, Dr. Tatsuo Izawa of Nippon Telegraph and Telephone Corp. (NTT) invented the vapor-phase axial deposition (VAD) method suitable for the mass production of optical fiber. NTT, Furukawa Electric, Sumitomo Electric, and Fujikura collaboratively investigated the fabrication process. The technology successfully shifted from research and development to commercialization. The VAD method contributed greatly to the construction of optical-fiber networks.
Street address(es) and GPS coordinates of the Milestone Plaque Sites
35.4407279, 139.314173, NTT Atsugi R&D Center, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-0198 Japan.
Details of the physical location of the plaque
The plaque will be placed near the reception area at the floor entrance hall. It will be displayed in a transparent hard case.
How the intended plaque site is protected/secured
NTT’s receptionists are always near the plaque. The plaque will be placed near the reception area at the floor entrance hall. All visitors have free access to this hall.
Historical significance of the work
From 1975 to 1983, NTT and three Japanese electric wire and cable manufacturers (Furukawa Electric, Sumitomo Electric, and Fujikura) worked collaboratively on the research and development of optical fiber for telecommunication. Then in 1977, NTT researcher Dr. Tatsuo Izawa invented the vapor-phase axial deposition (VAD) method for fabricating optical fiber preforms that were highly suitable for the mass production of optical fiber. The invention of the VAD method and the collaborative work to improve the process undertaken by NTT and the three electric wire and cable manufacturers established the basis for the low-cost mass production of high-quality low-loss optical fiber. The VAD method is currently the most used optical fiber fabrication method and accounts for more than 50% of the optical fiber used for telecommunications. The VAD method has contributed to the building of optical telecommunication networks that support our advanced information and communication society.
Features that set this work apart from similar achievements
With the VAD method, the porous glass preform is fabricated by the deposition of fine glass material via flame hydrolysis onto the end surface of a starting silica glass rod used as a seed. The starting rod is pulled upward, and the porous preform is grown in the axial direction. The porous glass is successively consolidated into a transparent glass preform for the fiber drawing process by arranging the melting zone region at the upper position in the axial direction. By contrast, other glass preform fabrication methods such as modified chemical vapor deposition (MCVD) and outside vapor deposition (OVD) require a collapsing process before they can prepare a transparent glass preform for fiber drawing. The fact that the VAD method does not need a collapsing process enables the continuous fabrication of a glass preform, which is preferable for the low cost mass production of optical fiber.
<Journal articles and conference papers>  T. Izawa, S. Kobayashi, S. Sudo, and F. Hanawa, “Continuous fabrication of high silica fiber preform”, Int. Conf. Integrated Optics and Optical Fiber Commun., 375, 1977.  T. Izawa, N. Shibata, and A. Takeda, “Optical attenuation in pure and doped fused silica in the IR wavelength region,” Applied Phys. Lett. Vol.31, No.1, pp.33-35, 1977.  T. Izawa, S. Sudo, and F. Hanawa, “Continuous Fabrication Process for High-Silica Fiber Preforms,” IECE of Japan, Vol.E-62, No.11, 1980.  F. Hanawa, S. Sudo, M. Kawachi, and M.Nakahara, “Fabrication of Completely OH-FREE V.A.D Fibre,” Electon. Lett., Vol. 16, No. 18, pp.699-700, 1980.  T. Izawa and N. Inagaki, “Materials and Processes for Fiber Preform Fabrication—Vapor-Phase Axial Deposition,” Proc. IEEE, Vol.68, No.10, pp.1184-1187, 1980.  T.Edahiro, S.Takahashi, K.Yoshida, M.Yoshida, and T.Shioda, “Long single-mode fiber made by vapor-phase axial deposition,” Proc. IOOC’1981, TUC2, pp.50-51, 1981.  M.Nakahara, N.Ingaki, K.Yoshida, M.Yoshida, O.Fukuda, “Fabrication of 100-km graded-index fiber from a continuously consolidated VAD perform,” Proc. IOOC’1981, WD4, pp.100-101, 1981.  M. Kawachi, M. Yasu, S. Tomaru, T. Edahiro, and S. Sakaguchi, “Wholly synthesized VAD single-mode fibre,” Electron. Lett., Vol. 18, No. 18, pp. 328-330, 1982.
<Patent>  T. Izawa, T. Miyashita and F. Hanawa, “ Continuous optical fiber preform fabrication method”, US Patent 4062665(Filed date: April. 5, Issued date: December 13, 1977)