Method of manufacturing optical fiber cable covered with metal pipe, and

Abstract

An apparatus for manufacturing an optical fiber cable covered with a metal pipe forms a metal pipe by abutting two sides of a metal strip to be pulled, introduces an optical fiber or an optical fiber bundle into the metal pipe, and seals the opening of the metal pipe by laser welding. A squeeze shoe is arranged immediately before a welding position. The inner circumferential surface of the squeeze shoe is brought into contact with the metal pipe, and the section of this inner circumferential surface conforms to the outer circumferential surface of the metal pipe. The squeeze shoe is vertically divided into halves. Since the squeeze shoe is provided immediately before the welding position, the opening of the metal pipe can have a predetermined width and be welded. The opening width is adjusted in accordance with at least one of a diameter, thickness and composition of the metal strip and in accordance with at least one of a welding rate, laser beam power and laser beam focus shift amount of the laser welder. Thus, thermal damage to the optical fiber can be reliably prevented, and defective welding caused by a spatter can be prevented, so that a long-time continuous operation is enabled. An elongated optical fiber cable covered with a metal pipe can be manufactured.