PURPOSE: To provide the subject vessel capable of giving a smooth flowing of a gaseous starting material without depositing of a soot and continuously operating for a long time.
CONSTITUTION: In this reaction vessel, a carbon reaction chamber 6 of a reaction vessel 1 to which an optical fiber F is introduced consists of a coating area part 6a and an exhausting area part 6b. The radius Y of an outer end part 1b of the exhausting part 6b is set to be larger than a radius X of the coating part 6a and the outer end part 1b is opened to the outer direction, and a structure in which a gaseous starting material C thermally decomposed at the coating area part 6a is exhausted through an opened side of the exhausting area part 6b is provided. Thus, a smooth flowing of the gaseous starting material is given without depositing a soot component to the inside of the reaction vessel, a uniform carbon coating on the surface of the optical fiber and long time operation in the reaction vessel become available.
NAKAHARA SHIGERU
NAGAE NOBUSADA
MORISAWA MASAAKI
TANAKA HIROYUKI
