Sumitomo Electric Industries, Limited

Nippon Telegraph and Telephone Public Corporation

Nippon Telephone and Telegraph Corporation

Sumitomo Electric Ind., Inc.

Shiro Kurosaki

Kunio Fujiwara

Satoshi Shiraishi

Minoru Watanabe

Takao Edahiro

Yuichi Usui

Tsuneo Nakahara

Masao Hoshikawa

Gotaro Tanaka

Nobuo Inagaki

Hideo Kakuzen

Shigeo Murai

Takeo Edahiro

An optical transmission fiber comprising (1) a core of high refractive index composed of SiO.sub.2 -based glass containing at least one of GeO.sub.2, As.sub.2 O.sub.3, Sb.sub.2 O.sub.5, SnO.sub.2, TiO.sub.2, PbO and Bi.sub.2 O.sub.3, (2) a clad of low refractive index composed of SiO.sub.2 -based glass containing at least one of F, F/B.sub.2 O.sub.3 and F/P.sub.2 O.sub.5, and (3) an outermost jacket layer composed of SiO.sub.2 and/or SiO.sub.2 -based glass containing at least one of Al.sub.2 O.sub.3, TiO.sub.2, ZrO.sub.2 and HfO.sub.2.

Optical transmission fiber and process for producing the same

An optical transmission fiber comprising (1) a core of high refractive index composed of SiO.sub.2 -based glass containing at least one of GeO.sub.2, As.sub.2 O.sub.3, Sb.sub.2 O.sub.5, SnO.sub.2, TiO.sub.2, PbO and Bi.sub.2 O.sub.3, (2) a clad of low refractive index composed of SiO.sub.2 -based glass containing at least one of B.sub.2 O.sub.3, F, F/B.sub.2 O.sub.3 and F/P.sub.2 O.sub.5, and (3) an outermost jacket layer composed of SiO.sub.2 and/or SiO.sub.2 -based glass containing at least one of Al.sub.2 O.sub.3, TiO.sub.2, ZrO.sub.2 and HfO.sub.2.

A process for producing an optical glass product having a predetermined distribution of refractive index in the interior of the product is disclosed. The process comprises the steps of:

Process for producing optical glass product

The present invention relates to a process for the production of an optical glass article, which comprises immersing a gelled body containing a compound capable of being converted into a dopant for increasing the refractive index of the glass, in a leaching liquor selected from the group consisting of water, aqueous solutions of weak acids, aqueous solutions of alkali metal salts, ketones and alcohols, leaching at least a part of the compound as ions out of the gelled body, optionally immersing the gelled body in an organic solvent, drying the body in a predetermined atmosphere, decomposing the compound, heating and firing the body at a high temperature and then heating and sintering it at a higher temperature.

Process for the production of an optical glass article

The present invention relates to a method of producing an optical waveguide by melt-drawing a transparent glass rod which has been produced by collapsing a doped porous glass rod. The glass rod is doped with refractive index enhancing dopant materials by depositing said material on the surface of the micro-pores wherein a waveguide having higher mechanical strength and lower transmission loss is obtained upon drawing said glass rod to a fiber. The drawing is performed at a temperature very close to the melting point of the outermost portion of the rod without causing any overmelting and resultant bubbling in the core portion. The drawing process is facilitated by matching the viscosity and softening characteristics of the outer, lower refractive-index portion of the rod to that of the central higher-refractive-index portion.

Method of producing optical waveguide

A process for producing a glass perform for optical transmission fibers, which includes supplying a gaseous silicon compound, ammonia or a gaseous nitrogen compound, and an oxygen-containing gas as starting gases into a high temperature zone to produce fine particles of SiOxNy glass and depositing the fine particles in the form of a soot or a transparent glass on a starting member to produce nitrogen-doped silica glass.

Process for preparing glass preform for optical fiber

This invention relates to a process for the production of an optical glass article, which comprises neutralizing an aqueous solution containing silicic acid to form a porous gelled body, removing soluble materials from the porous gelled body to form a porous glass body, stuffing the porous glass body with a solution containing at least one compound capable of being converted into an oxide dopant for changing the refractive index of the glass body, selected from the group consisting of CsNO.sub.3, RbNO.sub.3 and TlNO.sub.3, unstuffing the glass body with a solvent or solution having a suitable composition at a suitable temperature to leach the compound out of the outside glass body and to give a predetermined concentration distribution in the micropores of the glass body, optionally immersing the unstuffed body in an organic solvent, precipitating the compound in the micropores, drying the glass body in a predetermined atmosphere to decompose the compound, further heating at a higher temperature, and then firing at a temperature sufficiently high to completely decompose the compound and to completely burn the organic materials, but lower than the melting point of silica.

A method for producing an optical waveguide by melt-drawing a transparent glass rod which has been produced by collapsing a porous glass rod after being doped with a dopant material by depositing said material on the surface of the micro pores in order to enhance the refractive index of the collapsed glass rod, wherein a waveguide having higher mechanical strength and lower transmission is attained by drawing said glass rod at a temperature very close to the melting point of the outermost portion of the fiber without causing any overmelting or bubbling in the core portion, said drawing being facilitates by matching the viscosity and characteristics of the outermost lower-refractive-index portion to those of the central higher-refractive-index portion.

A process for producing an optical transmission fiber is provided which comprises feeding highly pure halides, hydrides or organic compounds of Si and B by way of carrier gas on the outer surface of a fused silica rod or a fused silica pipe, or inner surface of a fused silica pipe, oxidizing them and depositing the products to form a pure fused silica layer or a doped fused silica layer containing B.sub.2 O.sub.3, melting the pipe and the deposited layer followed by a spinning. The SiO.sub.2 layer can alternatively contain fluorine instead of B.sub.2 O.sub.3. A further SiO.sub.2 layer can be deposited thereon to improve the spinning processability and lower the index of refraction of the B.sub.2 O.sub.3 containing layer.

Process for producing optical transmission fiber

A process for producing a glass member includes subjecting a silicon, boron, phosphorous or aluminum compound or both a silicon, boron, phosphorous or aluminum compound and a dopant compound to vapor phase reaction to form a fine powder of fused silica, borate, phosphate or alumina or doped fused silica, borate, phosphate or alumina. Then the powder is partially sintered to form a porous glass body which subsequently is immersed in a solution containing a dopant compound thereby depositing the dopant compound on the surfaces of the pores in the glass body. Thereafter, the porous glass body is dried before the pores are collapsed to form the glass member.

Process for producing glass member

A method of manufacturing glass rod for optical waveguides is proposed. In this method, several gaseous mixtures or powdery mixtures of materials for glass forming are reacted at a high temperature and deposited on the top or end of a rotating glass rod which is initially deposited on a rotating base plate and grown in the form of a rod of a fixed powdery or vitreous state. It is possible to obtain the glass rod having a predetermined radial distribution of index of refraction.

Method of manufacturing glass for optical waveguide

A method of manufacturing an O-ring type optical waveguide wherein a layer of fused silica is formed on the smooth cylindrical surface of an elongated member of fused silica and thereafter a thin layer of doped fused silica having an index of refraction greater than that of said fused silica is formed over said layer of fused silica. A second layer of fused silica is then formed over the layer of doped fused silica and the composite structure is heated to its drawing temperatures and drawn to reduce the cross sectioned area thereof to form an optical waveguide having a cylindrical layer of higher refractive index interposed between a core and an outer cylindrical layer of lesser refractive index.

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Kanagawa, Japan

Shiro Kurosaki