Abstract: Impurities in an oxide superconducting layer or at a surface of the oxide superconducting layer at an intermediate layer side are reduced. A superconducting wire rod has a configuration that includes a metal substrate 10; an intermediate layer 20 formed on the metal substrate 10 and containing a rare-earth element that reacts with Ba; a reaction suppressing layer 28 formed on the intermediate layer 20 and mainly containing LaMnO3+?1, wherein ?1 represents an amount of non-stoichiometric oxygen; and an oxide superconducting layer 30 formed on the reaction suppressing layer 28 and mainly containing an oxide superconductor containing Ba.

Abstract: In a heating drawing, a base material glass plate is heated and softened in a heating furnace, and drawn to a desired thickness to form a glass strip. In the heating drawing, the base material glass plate is heated so that the base material glass plate has a U-shaped temperature distribution in a width direction. Such process can be realized through heating by a heating element which has a non-heating portion at a position opposite to a central portion of the base material glass plate in the width direction and a heating portion on both sides of the non-heating portion. Thus provided is a method of manufacturing a glass strip, the method includes heating and softening the base material glass plate, and drawing the base material glass plate to a desirable thickness to form a glass strip, and is capable of manufacturing a thin, rod-like glass strip with an excellent flatness.

Abstract: Methods of fabricating an optical fiber preform and a method of fabricating an optical fiber of the invention realize the fabrication of an optical fiber having desirable transmission characteristics in the entire wavelength rage of about 1.3 to 1.6 &mgr;m. The fabrication method comprises a porous core rod producing step of depositing a first cladding (3) having an outer diameter D so as to surround a core (2) having an outer diameter d to produce a porous core rod (1) of D/d≧4.0 by VAD. Then, the porous core rod (1) is dehydrated to reduce the OH group concentration to 0.8 ppb or less by weight ratio. The porous core rod (1) is formed to be transparent for a vitrified core rod (4) and is heated and stretched. Thereafter, a second cladding is obtained by depositing a second porous cladding (5) around the vitrified core rod (4) by VAD to be dehydrated, transparent and vitrified.

Abstract: The invention is directed to a photonic crystal defect structure for a vertical cavity surface emitting laser (VCSEL). In accordance with the invention, a set of holes is formed in a pattern with one or more missing holes forming a defect in the pattern of the photonic crystal, according to a proscribed depth, hole diameter, and pattern pitch which will insure operation in a single transverse mode.

Abstract: An optical switch includes at least one input optical semi-conductor waveguide. Two output optical semiconductor waveguides are connected at a branch point to the input optical waveguide, and diverge from the branch point with a preset angle .theta. (degree) between them. A refractive index controlling portion is located on at least one of the output optical waveguides and away from the branch point. The refractive index controlling portion effects a light mode cut-off by electromagnetically causing a reduction of the refractive index of the associated output optical waveguide.