The Furukawa Electric Co., Ltd.

Tsuguo Sato

Takeshi Yagi

Kazuaki Yoshida

Takayuki Morikawa

Masato Oku

Noritsugu Enomoto

Hiroshi Hihara

Kenichi Komura

The present invention provides a method of manufacturing a porous preform for an optical fiber, including the steps of removing impure particles from silica powder while being stirred in an alkaline liquid phase, and obtaining the porous preform for an optical fiber by applying the powder forming method to the silica powder used as a main raw material. The present invention further has a method of manufacturing a porous preform for an optical fiber, including the step of preparing a forming material by adding fine particles having a particle diameter satisfying the following formula (I) to the silica powder, and obtaining the porous preform by applying the powder forming method to the forming material: ##EQU1## wherein d: diameter of fine particles, and D: diameter of silica powder.

Method of manufacturing a porous preform for an optical fiber

The present invention provides a method of manufacturing an optical fiber preform having the steps of disposing a rod member made of a silica-based material within a cavity of a mold, followed by loading a molding material within the mold cavity, and applying pressure to the mold from the outside to form a porous layer on the surface of the rod member and, thus, to obtain a porous preform, wherein at least one end portion of the rod member extends outside the mold cavity in the step of applying pressure to the mold. The particular method permits manufacturing a high quality porous preform free from splits or cracks, making it possible to obtain a high quality optical fiber preform free from residual bubbles.

Method of manufacturing optical fiber preform

The method of manufacturing a silica glass preform comprises the steps of inserting a rod-like member mainly containing a ductile material, into a forming space of a mold, charging the remaining space of the forming space with a forming material containing silica glass powder or doped silica glass powder, compressing the mold charged with the forming material from outside such as to form a porous glass body of the forming material around the rod-like member, removing the rod-like member from the porous glass body, inserting a glass rod into the hole formed after removal of the rod-like member, purifying said porous glass body in which the glass rod is inserted, and consolidating said porous glass body purified in the above purifying step.

Method of manufacturing a silica glass preform

A method for splicing optical fibers is provided which is applied to an optical fiber using, as the material of a clad layer, hexafluoroalkyl methacrylate, a residuum of which after pryolysis due to a thermogravimetric analysis is 10% or less by weight. The method comprises a step of removing a protective layer and a cushioning layer at an end portion of the optical fiber, to expose the clad layer, a step of positioning two optical fibers, the end portions of which have been treated, such that the end faces of cores of the two optical fibers are opposed and close to each other, and a step of heating the end portions of the two optical fibers by electrical discharge, to remove the exposed clad layer by pyrolysis and fusion bond the opposed end faces of the cores to each other.

Growing community of inventors

Tokyo, Japan

Tsuguo Sato