Sumitomo Electric Industries, Limited

Nippon Telegraph and Telephone Public Corporation

Nippon Telegraph and Telephone Corporation

Masaaki Yoshida

Toru Yamanishi

Katsuyuki Tsuneishi

Gotaro Tanaka

Takao Edahiro

Toru Kuwahara

Hideo Kakuzen

Yuji Kameo

Masao Yuto

Naoya Uchida

Masaaki Kawase

Mitsuhiko Noda

Chihaya Tanaka

Shigeki Endo

Masao Watanabe

Shigeru Kisanuki

Kimio Tohma

Mikio Takeshima

An apparatus is provided for the production of a porous preform of SiO.sub.2 used in the manufacture of optical fiber wherein damage to the preform caused by falling clusters of SiO.sub.2 or GeO.sub.2 formed on the wall of the deposition chamber is eliminated. In accordance with the invention, a conductive shielding member is provided inside the wall defining the deposition chamber. This shielding member eliminates an electrostatic field produced on the wall by charging, therefore preventing the adherence of fine particles thereto.

Apparatus for producing porous preforms for optical fibers

A glass fiber for optical transmission comprising a glass fiber having provided thereon a first coating layer of a hardened resin and a second fluorine-containing resin layer formed by extrusion molding is disclosed. At least one of the first and second layers contains an adsorbable solid powder which is capable of adsorbing fluorine gas and/or hydrofluoric acid generated from the fluorine-containing resin during the extrusion molding. The glass fiber has an improved mechanical strength without adversely affecting transmission properties of the glass fiber.

Glass fiber for optical transmission

A method and apparatus for coating optical transmission glass fibers with a resinous composition. A vessel is provided through which a glass fiber is drawn. While it is being drawn through the vessel, the fiber is spun, and a resin coating is applied. In order to maintain the air pressure within the vessel fairly constant, an exhaust vent is provided through which excess particles of the resinous composition may escape. Turbulence is thus substantially reduced preventing the fiber from swinging and allowing the particles to be sprayed smoothly. Further, the particles may be electrically charged so that they are both attracted to the optical fiber and repel one another during flight. The invention employs both of these features to produce a uniform coat on an optical transmission glass fiber.

Method for coating optical transmission glass fibers

A process for producing high-purity silica glass wherein glass-forming chlorides, hydrogen gas, oxygen and an inert gas are supplied from a glass burner, the chlorides are decomposed by flame oxidation to form fine grains of glass which are deposited on a starting member and the glass deposit is sintered to provide a transparent vitreous substance, the volume ratio of oxygen gas to the sum of the chlorides and hydrogen gas being greater than about 0.6, preferably greater than about 1.0, and less than about 20.

Process for producing high-purity silica glass

A glass fiber for use in optical transmission which comprises a first layer containing an organopolysiloxane having a refractive index higher than that of the glass which forms the outermost layer of the glass fiber, a second layer comprising an organopolysiloxane which is the same or different than the organopolysiloxane in the first layer, and a thermoplastic resin coated on the second layer in a thickness less than about 100 microns.

Coated glass fibers for optical transmission

In a glass fiber for optical transmission comprising a primary coat, a thermoplastic resin coat, and a buffer coat between the primary coat and the thermoplastic resin coat, the improvement which comprises said thermoplastic resin being a polyamide having a modulus of elasticity of about 2,000 to 8,000 kg/cm.sup.2 at a temperature in the range of 20 to 23.degree. C.

A method for the treatment of rubber and plastic wastes, comprising in series the steps of

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Kanagawa, Japan

Masaaki Yoshida