Mitsubishi Cable Industries, Ltd.

Hiroyuki Tanaka

Atsushi Utsumi

Takeshi Satake

Tamotsu Kaide

Toshihiro Zushi

Nobusada Nagae

Toshikazu Gozen

Shigeru Nakahara

Tetsuya Takeda

Masaaki Morisawa

Toshiya Suzuki

A method for producing a silica glass optical fiber, which comprises coating carbon on the optical fiber with the use of the remaining heat of not less than 800.degree. C. possessed by the optical fiber just after heat wire drawing, for thermal decomposition of a carbon coat-forming gas comprised of one or more members selected from the group of halogenated hydrocarbons, hydrocarbons, and halogen molecules, which has 5 to 15 hydrogen atoms per 10 halogen atoms, and a reaction apparatus for coating carbon, wherein the area of the outer end of an exhaust region is greater than the transverse sectional area of a coating region, and the outer end is outwardly opened. The production method and the reaction apparatus therefor of the present invention are advantageous in that the optical fiber thus obtained has superior properties in terms of resistance to water, resistance to hydrogen, and mechanical strength, specifically tensile strength, that sedimentation of the soot component in the reaction apparatus can be prevented, that the flow of the material gas can be made smooth, that a uniform carbon coat can be formed on the surface of the optical fiber, and that long-term operation of carbon coating apparatus can be made possible.

Method for producing silica glass optical fiber with carbon coating

The present invention relates to an energy transmission optical fiber which is a medium for transmitting high-energy beams within an ultraviolet range such as laser beams. Since an optical fiber according to the present invention comprises a core formed of pure silica and a clad having a graded index type distribution of refractive index and said clad is disposed on an interface between the core and the clad where many structural defects are generated, the transmission loss is not increased even after the transmission of high-energy beams for a long time. In addition, since the optical fiber according to the present invention comprises the core formed of pure silica having a high melting point, the high-energy beams can be transmitted without generating a melting fracture in the core.

Energy transmission optical fiber

Growing community of inventors

Itami, Japan

Hiroyuki Tanaka