Abstract: A granular body, from which an article having a nonuniform refractive index may be formed, has grains of two substances which have different refractive indicies in a geometric distribution in the granular body corresponding to the geometric distribution of the substances required for the nonuniform refractive index of the article and a way of shape-stabilizing the granular body. A method of making the granular body comprises controllably feeding the grains into the geometric distribution in the granular body and shape-stabilizing it. Preferably the granular body is compressed into a porous compact which holds itself together and is treated with a gas to achieve desired optic properties in the article.

Abstract: A process for producing a single-crystal substrate of silicon carbide comprises growing a single-crystal film of .alpha.-silicon carbide on a single-crystal film of .beta.-silicon carbide as a growth substrate, thereby obtaining a high quality single-crystal substrate of .alpha.-silicon carbide having a large area, which is producible on a commercial scale.

Abstract: In order to provide a substrate such as an optical preform rod (24) which is suitable for insertion into a tube and which has a transverse cross section that is substantially circular and disposed concentrically about a longitudinal axis of the substrate substantially along its entire length, a force-applying member such as a graphite roller (52) is moved incrementally toward an axis of rotation (35) about which the preform rod is turned rotatably. Movement is discontinued when there is an indication that the force-applying member has been in continuous engagement with the preform rod for at least a predetermined portion of the periphery of the rod. In a preferred embodiment, the engagement of the force-applying member and the preform rod is discontinued after a predetermined time whereafter the force-applying member again is moved toward the axis of rotation.

Abstract: This specification discloses a mold for use for press-molding an optical element, characterized in that at least the molding surface of a mold base material is coated with an a-C:H film containing 5-40 atom % of hydrogen therein and having a film density of 1.5 g/cm.sup.3 or more. Other mold coating films also disclosed are a hydrogenated amorphous carbon film with an intermediate carbide layer between the film and the molding surface, and a hard carbon film containing 0-5 atom % of hydrogen therein and having a spin density of 1.times.10.sup.18 spin/cm.sup.3 or less and a film densisy of 1.5 g/cm.sup.3 or more.

Abstract: The present invention relates to a novel dry-etching method for patterning a metallic film, whose surface is provided with an oxidized film, into an optional configuration by the use of the oxidized film. After drawing etching patterns of the metallic film by irradiating energy beam to the oxidized film formed on the surface of the metallic film, the dry-etching method according to the present invention causes the metallic film to expose itself to either radicals of reactive gas or to etching gas, and then selectively removes the area of metallic film in correspondence to the beam irradiated area of the oxidized film by applying chemical etching, thus eventually allowing the metallic film to be patterned into an optional configuration, without incuring physical damage to the etching face of the metallic film.

Abstract: A method for producing a .lambda./4 shift type diffraction grating by producing a diffraction grating pattern on a substrate with a material capable of being selectively etched relative to the substrate, depositing a resist to bury the diffraction grating pattern, removing a portion of the resist to expose at least a portion of the surface of the diffraction grating pattern, removing the diffraction grating pattern on a first portion of the substrate, etching the first portion of the substrate using the remaining resist pattern as a mask, and etching a second portion of the substrate adjacent to the first portion using the remaining diffraction grating pattern on the second portion of the substrate, thereby producing a .lambda./4 shift type diffraction grating having a .lambda./4 phase shift region at the junction of the first and second portions of the substrate.

Abstract: A refractive index profile in a glass article is easily controlled by heating a solid or hollow cylindrical glass soot preform in an atmosphere comprising a fluorine-containing compound under such conditions that a partial pressure of the fluorine-containing compound is changed as the heating proceeds so as to control a fluorine concentration in a radial direction of the optical glass article.

Abstract: Viaholes are dry-etched into glass fiber reinforced plastic sheets according to a predetermined hole pattern, leaving the glass fiber meshing practically unaffected.The method is used, for instance, to fabricate plastic sheets with unilaterally or bilaterally applied conductor patterns and viaconnectors that are conductively linked to the conductor patterns, and to fabricate multilayer board laminates obtained by several plastic sheets carrying the conductor pattern being alternately packaged, if required, with untreated copper sheets, and by the package thus obtained being subsequently laminated. Such boards and/or plastic sheets bilaterally provided with conductor patterns may be used as connector boards for, say, multilayer ceramic modules carrying semiconductor chips.

Abstract: A process for manufacturing an optical fiber includes the steps of heating and drawing material from a hot optical fiber preform; depositing a conductive coating (especially carbon) on the moving optical fiber; putting a heat curable liquid material on the moving optical fiber; and curing the heat curable liquid material by inductively heating the conductive coating on the moving optical fiber in an electromagnetic field. Heat induced into the conductive coating by energy from the field is conducted from the conductive coating to the heat curable material. The optical fiber continuously moves through the steps of the process without any physical contact.

Abstract: An apparatus for wet etching of thin films with which etching rate differences as between various regions of a respective thin film down to only 5% can be achieved. The apparatus includes a housing (10) providing a liquid treatment chamber in which at least one rotational-symmetrical basket (12; 14) is arranged for accommodating semiconductor slices (16) having the thin films to be etched. The basket (12, 14) rests on two rollers (18, 20; 22), one of which is driven. Longitudinally above the basket (12; 14), flat jet nozzles (24) are arranged in such a manner that the jets of etching solution sprayed out of the nozzles form a homogeneous flat jet (26). The flat jet (26) is directed laterally in the direction of the axis of symmetry of the basket (12; 14). With this apparatus, overflow conditions on the surfaces of the slices (16) to be processed are obtained which are so uniform that the apparatus is suitable for use in the wet etching of aluminium layers in device fabrication.

Abstract: A fiber optic coupler is formed by assembling a coupler preform having two concentric glass tubes having a gap between them. The shape and/or size of the inner tube relative to the shape and/or size of the outer tube is such that a plurality of output optical fibers can be equally spaced in the gap. An input optical fiber is disposed in an aperture in the inner tube. The input and output fibers extend through the midregion of the resultant coupler preform. The midregion is heated to collapse it about the fibers, and the central portion of the midregion is stretched to reduce the diameter over a predetermined length.

Abstract: A tool consists of an array of field-emitting nanostructure probe tip extensions on the end of a metal probe. The probe is tapered to a long, narrow, flat end with typical dimensions of 1 cm.times.1 .mu.m. The probe tip extensions typically extend approximately 100 .ANG. beyond the probe surface and their ends are shaped to act as independent field-emission tips, each at an exact atomic location. These ends are a single crystal plane terminating in a single crystal unit plane cell having a central atom with a lower work function than the atoms surrounding the central atom. The nanostructures are spaced in a prescribed, repeating pattern with typical spacings on the order of 400 .ANG.. The probe voltage, current and position, as well as CVD or etching gas pressures, are sequentially adjusted to fabricate nanostructures on a nearby substrate, which is typically 10-30 .ANG. below the termination points of the probe tip extensions.

Abstract: A parallel plate reactor having a grounded grid disposed between an RF powered electrode and a grounded electrode upon which a substrate is disposed. A method of utilizing the above apparatus consists of etching the substrate using a composition of 30-100% NF.sub.3 (nitrogen trifluoride) at 25 SCCM (standard cubic centimeter per minute) and 0-70% He (helium) at 75 SCCM to etch a layer of PECVD (plasma enchanced chemcial vapor deposition) Si.sub.3 N.sub.4 (silicon nitride). The etching takes place at 200 mtorr to 5 torr pressure and 50-400 watts RF power.

Abstract: A new, simplified method of fabricating optically transparent fluoride glasses containing ZrF.sub.4 and/or HfF.sub.4 has been developed which relies on a high vacuum pre-treatment for surface dehydration, melting in a rigorously inert argon atmosphere, and incorporation of a nonvolatile metallic oxidant in the melt such as InF.sub.3 and SnF.sub.4. Previous method for making these glasses have relied on either addition of ammonium bifluoride into the batch materials, or melting in an oxidizing atmosphere (so-called reactive atmosphere processing or RAP); both of these latter techniques have significant drawbacks.

Abstract: A sacificial fiber method to fabricate straight, curved, or coiled tubes as small as 1 micron (0.000004 inches) in diameter with wall thicknesses starting at less than 0.01 microns. These tubes can be made from many of the materials that can be applied to a surface of carbon, glass, or other tube forming fibers and then made to withstand the environment used to remove the fiber. A monolithic piece can be formed where the tubes are channels or holes.

Abstract: The method of producing a hermetic stable structural bond between quartz crystals includes providing first and second quartz crystals and depositing thin films of borosilicate glass and silicon on portions of the first and second crystals, respectively. The portions of the first and second crystals are then juxtaposed in a surface contact relationship and heated to a temperature for a period sufficient to cause the glass and silicon films to become electrically conductive. An electrical potential is then applied across the first and second crystals for creating an electrostatic field between the adjoining surfaces and causing the juxtaposed portions to be attracted into an intimate contact and form a bond for joining the adjoining surfaces of the crystals.

Abstract: A fiber optic coupler is formed by providing a glass tube having a longitudinal aperture. Glass optical fibers, each having a core, cladding and coating are disposed within the longitudinal aperture, the fibers extending beyond each end of the tube. The coating is removed from that portion of the fibers in the midregion of the tube but remains on that portion of the fibers extending into the ends of the apertures. The aperture is formed by a plurality of flattened walls, the dimensions and orientations of which are such that the cross-section of the aperture in the central region of the tube is symmetrical with respect to a plane passing through the longitudinal axis of the tube. At any cross-section of the aperture that is adjacent the coated regions of the fibers, each fiber coating contacts two walls of the aperture. The fibers are held taut to effect a tension, and the midregion of the tube is heated, collapsed about the fibers, and drawn to reduce the diameter thereof over a predetermined length.

Abstract: A metal film (12) for providing internal electrodes (22) is formed on a back film (11) made of a material such as polyethylene terephthalate by a thin film forming method such as vapor deposition or sputtering. A ceramic green sheet (14) is prepared. Then the metal film (12) is transferred onto the green sheet from the back film (11). In order to form the metal film (12) to be transferred into prescribed patterns, the metal film (12) may be partially removed from the back film (11) to leave only specific parts which are correlative with the prescribed patterns. Alternatively, only specific parts, which are correlative with the prescribed patterns, of the back film (11) may be pressed against the ceramic green sheet (14). A plurality of such ceramic green sheets (14), onto which the parts of the metal films (120 are transferred, have been stacked with each other.

Abstract: A process for producing porous glass, which comprises preparing a reaction solution containing a metal alkoxide or its oligomer and an organic polymer, hydrolyzing and polymerizing the metal alkoxide or its oligomer in the solution to obtain a gel, and calcining the gel to obtain porous glass, wherein the organic polymer has compatibility with the solution of the metal alkoxide or its oligomer, undergoes phase separation during the hydrolysis-polymerization step and is substantially free from formation of precipitates.

Abstract: An apparatus for the implementation of plasma etching processes providing a process chamber, an upper electrode, and a lower electrode. The upper electrode comprises an anode member, movable with respect to the process chamber, and provides a gas shower for delivering a highly reactive gas, such as a gas containing fluorine or chlorine, into the process chamber. The lower electrode provides a surface for holding a substrate to be etched, the lower electrode being supplied with a high-frequency negative voltage and cooled by an outside source. The process chamber is shaped to press the substrate to the lower electrode when the process chamber is lowered upon the substrate in preparation for operation. The process chamber presses the substrate around a continuous periphery of the substrate. The process chamber is provided with exhaust gas export holes which can be progressively aligned with matching holes in a perforated disk rotatably mounted to an outside surface of the process chamber.