Sumitomo Electric Industries, Limited

Other

Nippon Telegraph and Telephone Public Corporation

Shigeo Murai

Minoru Watanabe

Pedro B Macedo

Joseph H Simmons

Shiro Kurosaki

Shintaro Miyazawa

Yuichi Usui

The quality of a compound semiconductor crystal such as gallium arsenide used for an integrated circuit is upgraded by a method comprising optionally forming a protective film on the obverse surface and reverse surface of a substrate consisting of a compound semiconductor crystal, subjecting the substrate to a heat treatment in an inert atmosphere at a temperature of at least the same as the activating temperature after the ion implantation into the substrate and then optionally revmoving the protective film.

Method of homogenizing a compound semiconductor crystal prior to

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 method of producing a glass article having a graded refractive index profile of a parabolic nature is disclosed. The method comprises soaking a preform having a porous matrix with interconnected pores into a stuffing solution containing at least one index modifying dopant of predetermined solubility in the stuffing solution for a time interval to fill the pores with the dopant solution, precipitating the dopant into the porous matrix approximately uniformly throughout, soaking the preform into a solvent solution having a solubility for the dopant lower than the solubility of the dopant in the stuffing solution for a time interval sufficient to cause substantially all of the dopant to redissolve and for diffusion to take place out of the porous matrix in such a way that the dopant concentration decreases as a function of radial distance from the central axis, precipitating the dopant in the porous matrix by reducing the temperature of the preform to a level such that the dopant is precipitated out of solution, removing the solvent and where necessary decomposition products from the preform, and heating to consolidate the preform to produce a glass article having a graded refractive index profile of the parabolic nature.

Method of producing a glass article having a graded refractive index

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Kyoto, Japan

Shigeo Murai