Japanese Telecom operator NTT along with world’s leading optical fiber and cable suppliers such as Fujikura, Furukawa and Sumitomo has been honored by IEEE for their milestone achievement and contribution to the optical communication networks by developing an innovative preform manufacturing method called VAD (Vapor Axial Deposition). The prestigious IEEE Milestone award has been handed over to the representatives of the companies in a function held at Tokyo on 21 May. Nippon Telegraph and Telephone Corporation (NTT, Chiyoda-ku, Tokyo, President and CEO: Hiroo Unoura), Furukawa Electric Co., Ltd. (Furukawa Electric, Chiyoda-ku, Tokyo, President: Mitsuyoshi Shibata), Sumitomo Electric Industries, Ltd. (Sumitomo Electric, Chuo-ku, Osaka, President: Masayoshi Matsumoto), and Fujikura Ltd. (Fujikura, Koto-ku, Tokyo, President and CEO, Yoichi Nagahama) received the prestigious IEEE Milestone award in Electrical Engineering and Computing from the Institute of Electrical and Electronics Engineers (IEEE) in recognition for achieving the vapor-phase axial deposition (VAD) method.
VAD is an excellent technique for the mass production of high-quality optical fiber, which is the heart of an optical fiber cable. The collaborative research and development the team undertook contributed to a worldwide acceleration of deployment of fiber optic communication networks. During 1970s there was an increased interest and enthusiasm among young scientists to do research on glass optical fiber hoping that it will provide future optical transmission medium for long distance communication. In Japan, the telecom service provider NTT and the manufacturers Fujikura, Furukawa and Sumitomo jointly established a research and development team. The team started working together with the target of developing silica-glass optical fiber for mass production. In 1977, they achieved a significant result by developing the Vapor-Phase Axial Deposition (VAD) method, which proved to be highly suitable and practical for mass production of optical fibers.
More than 60% of the optical fibers produced worldwide belongs to VAD method today. VAD method greatly contributes to the construction of optical telecommunication networks worldwide.
The invention of the VAD method by the Japanese team and their collaborative efforts to improve the fabrication processes established the basis for the low-cost mass production of high-quality optical fiber. Thus the optical fibers produced by these manufacturers are based on the same method called VAD. NTT in Japanese telecom market ensure compatibility of their network by using optical fiber cables from these leading fiber and cable suppliers. Optical fibers drawn out of the same preform manufacturing method would ensure greater compatibility and integrity required for the long-term reliability and error-free transmission over optical networks.
While selecting optical fibers for your network, it is important to ensure the compatibility of optical fibers for reliability of the communication signals. While it is always better to use optical fibers from a single manufacturer, there may be some unforeseen situations where you will be forced to use optical fiber cables from different suppliers. In that case too, you have the choice ensure that base preform manufacturing method used by optical fiber manufacturers are same.
What is VAD Method?
In simple words, VAD or Vapor-Phase Axial Deposition is one of the most popular optical preform manufacturing methods. Optical fiber for communication is fabricated by drawing a fine thread of fiber from a glass cylinder called a preform. The preform shall be heated to draw fiber. Ability for mass production and the characteristic of low attenuation are two important criteria that makes a preform manufacturing method widely acceptable to manufacturers. The development of a method for manufacturing large optical fiber glass preforms quickly was a key issue for manufacturers when going for mass production of optical fiber.
In VAD method, a porous glass preform is fabricated by the deposition of fine glass material (SiO2-GeO2) onto the end surface of a silica glass rod via flame hydrolysis. The glass rod is used as a seed from which to form an inner deposition part whose outer part is covered with SiO2 glass fine particles by flame hydrolysis. The starting glass rod is pulled upward in the axial direction and the porous preform is grown in the same direction. This process allows the growth of a long and large-diameter porous preform. The porous preform is then heated to create a transparent fiber preform. Optical fiber is obtained by drawing the fiber preform. Other glass preform fabrication methods include modified chemical vapor deposition (MCVD), outside-vapor deposition (OVD) and Plasma Chemical Vapor Deposition (PCVD).