초록 ▼

For making a preform for production of optical fiber, the preform including fused silica, particulate material is deposited on the inside wall of a glass tube while the tube is reciprocated through a microwave cavity for production of a plasma in the tube. Oxygen and a reactant gas containing silica

For making a preform for production of optical fiber, the preform including fused silica, particulate material is deposited on the inside wall of a glass tube while the tube is reciprocated through a microwave cavity for production of a plasma in the tube. Oxygen and a reactant gas containing silica are passed through the tube. Dopant material can be added to the gas mixture and the concentration of the dopant varied to vary the refractive index. After the deposit of a sufficient thickness of particulate material, it is fused. The material can be caused to fuse on to the inner wall of the tube or to shrink away from the inner wall and removed from the tube. When the material is fused onto the wall of the tube it can then be collapsed, then either drawn to a fiber or placed in a further tube and drawn to a fiber. When the fused material shrinks from the tube wall, then it is collapsed to a solid rod, placed in a tube and then drawn to a fiber.

대표청구항 ▼

A method of manufacturing an optical fiber preform, comprising: providing a glass tube; positioning said tube in a microwave cavity; feeding a carrier gas through said tube; applying a microwave field to said cavity to produce a plasma in said tube at a position in said cavity, the power supplied be

A method of manufacturing an optical fiber preform, comprising: providing a glass tube; positioning said tube in a microwave cavity; feeding a carrier gas through said tube; applying a microwave field to said cavity to produce a plasma in said tube at a position in said cavity, the power supplied being sufficient to maintain a temperature on the inner wall of said tube below about 500°C.; feeding a reactant gas containing silica in a vaporous form through said tube; reciprocating said tube through said cavity for a predetermined plurality of times to build up a deposit of particulate silica on the inner wall of said tube; heating said tube to provide a temperature on the inner wall of said tube of about 1500°C. to 1700°C.; and traversing the tube through said cavity to fuse said deposit to form a fused layer of silica.