Abstract: A method of adjusting the operation of bimodal optical networks in terms of propagation constants of guided modes in integrated optical devices, allowing a considerable number of out of tolerance devices to be recovered by depositing on the surface where the optical guides are manufactured, once the normal fabrication process is completed, a further layer of transparent material of suitable size and refractive index.

Abstract: Spherical products of a heat-softened material are produced by supplying a molten heat-softened material into a C-shaped channel-like spinner with an open upper surface and a large number of orifices formed in its circumferential wall, at a rate of 0.020 kg/hr or lower per a single orifice of the spinner; rotating the spinner at a high speed to form cone-like fine streams of the molten material from the orifices by means of a centrifugal force; and flowing streams of a hot gas so as to traverse the fine streams of molten material to thereby heat the same resulting in reducing the viscosity of the molten material and to break the fine streams by the hot gas streams.

Abstract: A method of etching the surface of a substrate in a closed environment including the steps of contacting the surface of the substrate with a molecular chlorine etching gas, allowing a passivation layer to form on the surface of the substrate with atomic layer precision, and photochemically removing at least a portion of the passivation layer by irradiating the portion without destruction of the layer of material immediately underlying the passivation layer.

Abstract: A coating apparatus in which a series of substrates are conveyed along a predetermined path for receiving coating solution in which coating is carried out stably and coatings of uniform thickness are formed. A solution supplying unit is arranged above the path of the substrates. A flexible, elastic solid curtain member made of a water-impermeable material is attached to an outlet of said solution supplying unit, a front edge of which elastically contacts the substrates as they pass beneath the solution supplying unit so that coating solution flowing out of said solution supplying unit is applied to the substrates from the curtain member. A vertically movable solution receiver is positioned below the front edge of the curtain member with the solution receiver contacting the front edge of the curtain member when no substrate is located between the curtain member and the solution receiver so as to allow the coating solution to smoothly flow down the solution receiver.

Abstract: A method for fabricating a high efficiency optical coupler by matching the emerging light exit pupil from a coupler opening to the acceptance shape of a couple optical fiber. An excimer laser forms the coupler opening in an optical fiber by removing cladding from the optical core surface. The coupler opening has an elliptical shape resulting in an emerging light exit cone, and that exit cone matches an acceptance cone of a circular coupler optical fiber.

Abstract: Polarization-retaining optical fibres are manufactured according to the PCVD method, in which on the inside of a glass tube and, simultaneously on at least two glass rods which are arranged inside the glass tube such that their longitudinal axes run parallel to the longitudinal axis of the glass tube, glass is deposited in layers and the glass rods are removed from the glass tube upon completion of the glass deposition process. Alternatively, a single glass rod, the radial dimensions of which in two mutually perpendicular directions are in a ratio unequal to one, i.e. elliptical, is arranged in a glass tube such that its longitudinal axis coincides with the longitudinal axis of the glass tube.

Abstract: This invention relates to a sintering furnace for the production of a quartz preform which can be used for carrying out dehydration, fluorine-addition and/or sintering of a porous quartz soot preform prepared by a flame hydrolysis method such as a VAD method or a OVD method, and in particular, to such a furnace in which joints in a long furnace muffle so long that fabricating it as open body is impossible can be maintained fully gas-tight, so that it is possible to prevent H.sub.2 O, O.sub.2 and other impurities in the air from entering the muffle from outside, and corrosive and poisonous gases in the muffle are prevented from leakage to outside the muffle.

Abstract: A method is provided for making a hermetically sealed package for a power semiconductor wafer having substantially entirely silicon materials selected to have coefficients of thermal expansion closely matching that of the power semiconductor wafer. A semiconductor wafer such as a power diode includes a layer of silicon material having first and second device regions on respective sides. An electrically conductive cap and base of silicon are disposed in electrical contact with the first and second regions of the semiconductor device, respectively. An electrically insulative sidewall of silicon glass material surrounds the semiconductor wafer, is spaced from an edge thereof, and is bonded to the cap and base for hermetically sealing the package.

Abstract: An article for use in producing silica optical fibers doped with a metal de obtained by synthesis from low pressure vapor reactants is made from an outer supporting tube extending along a longitudinal axis and having first and second longitudinally opposite ends and an inner surface on which silica and a dopant formed by a reaction between vapor-state reactants can be deposited over a longitudinally extending silica-deposition zone. Respective first and second joints engage the ends of the supporting tube and each have a fixed part and a rotating part. Each rotating part supports the respective end for rotation relative to the respective fixed part about the axis. At least one of the reactants is introduced into the supporting tube through the first joint and depleted gases are discharged through the second joint.

Abstract: An optical waveguide preform is fabricated by inserting a rod inside a tube and collapsing the tube. The inner diameter of the tube is adjusted before inserting the rod to provide a predetermined gap width between the inner surface of the tube and the outer surface of the rod. The gap width is selected as a function of the cross sectional area of the tube in order to minimize core eccentricity in the finished waveguide.

Abstract: A buried wave guide device is produced by immersing a phosphate glass containing exchangeable ions in a molten salt. Ions are exchanged from the phosphate glass to give a wave guide whose refractive index increases sharply from a first surface to a maximum at a depth below the first surface then decreases gradually in the direction of the opposite surface.

Abstract: The present invention relates to a mold for producing glass articles comprising a glass-made mold base, an intermediate layer formed by a silicon carbide and/or silicon nitride film, and an uppermost layer formed by a carbon film. Since the mold for producing glass articles exhibits an excellent bonding between the glass-made mold base and the uppermost layer formed by the carbon film, peeling of the uppermost layer can be prevented. Therefore, the function of the uppermost layer as an adhesion-prevention layer against the glass to be molded can be exhibited for a long time, causing an economic advantage since the life of the mold can be lengthened. In addition, since the maximum surface roughness of the working surface of the mold can be reduced and the surface shape accuracy can be maintained, a molded glass article exhibits excellent surface accuracy without optical defects.

Abstract: A method for manufacturing a glass container by the steps of (a) providing a plunger with two portions, one portion having a sprayed metal coating of self-fluxing alloy and the second portion having a ceramic coating, (b) forming a lubrication carbon layer on surfaces of molds including a blank mold and a neck ring by periodically injecting flames of at least one kind of gaseous hydrocarbon having a carbon to hydrogen ratio more than 0.75, (c) supplying a gobbet of glass to the blank mold; (d) producing the parison from the gobbet of glass, using the plunger, the blank mold and the neck ring; and (e) blow-forming the parison to a glass container of a final configuration.

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 means such as a graphite roller (52) is adapted to be moved incrementally toward an axis of rotation (35) about which the preform rod is turned rototably. Movement is discontinued when there is an indication that the force-applying means 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 means and the preform rod is discontinued after a predetermined time, whereafter the force-applying means again is moved toward the axis of rotation.

Abstract: A transport device for boards having a sensitive surface, especially for wet-coated circuit boards, comprises, within a common housing, a lacquering station and, arranged above the latter, a drying region. For transporting the boards (2) through the drying region holders (3) are provided which comprise at least two bars (30) each having rows (31,32) of prongs extending from a bar (30) in a "V" shape and arranged in the form of a rake. The free ends of the prongs of the one bar point towards the free ends of the prongs of the other bar. The bottom ends of the holders (3) are open. For supporting the bottom ends (2b) of a board (2) that is being transported in a holder (3), the transport device is equipped with a supporting device (12) that is movable synchronously with the holders (3).

Abstract: A transport device (1) for boards (2) or board-shaped workpieces, especially those having a sensitive surface, preferably for circuit boards which are coated with plastics material, for example UV-hardenable plastics material, with lacquer or the like and then dried, is constructed as a circulating coating system. The device (1) has holders (3) for taking hold of the boards (2) at the edges (2a) thereof when they are being handled, and advancing means, advantageously in the form of chains, for transporting those holders (3). The holder (3) has two parallel bars (10) on each of which there are provided two rows (11, 12) of prongs (13) arranged in the form of a rake, the prongs (13) of the one row (11) of a bar (10) forming an acute angle with those of the second row (12) of that bar (10) and the two rows (11, 12) accordingly being arranged with respect to each other in a "V" shape when viewed in cross-section.

Abstract: A method of production of mono- or multimodal lightwave guides from special substrate glasses of the glass system SiO.sub.2 -B.sub.2 O.sub.3 -Al.sub.2 O.sub.3 - K.sub.2 O-F.sup.-, with partial exchange of the Li.sup.+, Na.sup.+, and/or K.sup.+ ions present in the glass against Cs.sup.+ ions, the substrate glasses having the following compositions (in mol.-%): SiO.sub.2 45-72, B.sub.2 O.sub.3 8-25, Al.sub.2 O.sub.3 1-25, Li.sub.2 O 0-1, Na.sub.2 O 0-2, K.sub.2 O 6-18, MO 0-1 (MO= MgO, CaO, SrO, BaO, ZnO, PbO), in which a portion of the O.sup.- ions present in the glass are replaced by 1-15 mol % F.sup.- ions.

Abstract: A phototreating method comprises the steps of introducing a photoreactive gas into a chamber housing a workpiece, emitting first light substantially perpendicularly to a surface of the workpiece, and emitting second light substantially perpendicularly to the surface of the workpiece simultaneously with or after radiation of the first light. The surface of the workpiece is coated utilizing a photochemical reaction of the photoreactive gas caused by radiation of the first light and the second light.

Abstract: A gob of glass sucked from a glass metal and held in a suction mold (7) is further processed by preshaping the glass in the mold by a punch (4) having a projection (9) for forming in a recess or cavity (14) in the gob in the opening in the mold, and a plate-like surface (10) for forming a plate shaped bead (5) around the opening. This results in a large contact surface against which a blowpipe (1') with a transverse attachment plate (6) having a working surface flush with the end of the bore (3) of the blowpipe is pressed to attach the plate (6) to the bead (5). With this arrangement, the bore cannot become blocked with glass during the pressing operation.

Abstract: The present invention providesa process for the dehydrating and purifying treatment by heating a porous glass preform for an optical fiber by passing the porous glass preform through a muffle tube having a SiC layer at least on its inner surface at a high temperature under an atmosphere containing an inert gas and a silicon halogenide gas;a process for the fluorine-doping treatment by heating a porous glass preform for an optical fiber by passing a porous glass preform through a muffle tube having a SiC layer at least on its inner surface at a high temperature under an atmosphere containing a fluorine compound gas and an inert gas; anda process for the vitrifying treatment by heating a porous glass preform for an opticla fiber by passing the preform, which has been previously dehydrated and purified, through a muffle tube having a SiC layer at least on its inner surface at a high temperature under an atmosphere gas.