Abstract: A method of encapsulating microelectronic devices. A jet of gas is directed to an area of the device which is to remain free from encapsulating material. Polymerizable encapsulating material is then applied to the device. The material flows around the region upon which the jet impinges. The material is then cured.

Abstract: A single-mode optical waveguide is constructed in a manner such that the core thereof is subjected to a stress-induced birefringence. A single-mode optical fiber preform is formed by a CVD process. A pair of longitudinally extending holes is formed on opposite sides of the core, spaced slighty therefrom. A stress rod having a TCE different from that of the cladding portion of the preform is inserted into each hole. The space between the holes and the rods is evacuated. The resultant composite structure is drawn into an optical fiber. A similar method is used to form a fiber having multiple light conducting cores, this method differing in that the rods which are inserted into the holes are formed of a glass having a refractive index greater than that of the cladding portion of the preform.

Abstract: Disclosed is an optical fiber for operating single polarization, single-mode at wavelength .lambda.. The fiber core is surrounded by cladding having the refractive index lower than the average refractive index of the core. The core is characterized in that it comprises a plurality of transparent laminae, each having a refractive index different from that of the adjacent laminae. The thickness of each laminae is equal to or less than wavelength .lambda..

Abstract: Optical fibers are coated under pressure to reduce the amount of bubbles entrapped in the coating and provide good coating concentricities. The fiber is drawn axially thru a thin-walled, cylindrical flow distribution sleeve which is located between a guide die and a sizing die. The sleeve contains a plurality of evenly distributed holes the number and size of which is such that radial flow of liquid toward the fiber is maintained over the entire length of the sleeve which is less than 1.27 cm.

Abstract: A process for manufacturing a preform from which is drawn an optical fiber, the core of which comprises layers of different glass composition. In one embodiment, the known CVD process for making preforms is modified by halting rotation of the substrate tube while the tube is asymmetrically heated by a source that traverses the length of the tube. A vapor mixture flowing through the tube reacts only near that region of the inner surface of the tube that is being heated. This forms a longitudinal strip of glass particles. The flow of reactants stops, the tube is rotated, and it is traversed by heating means which heats the tube to a temperature sufficiently high to fuse the glass particles and forming a longitudinal strip of glassy material.

Abstract: Disclosed is an optical waveguide fiber coating system having means for cooling the hot fiber prior to the time that the fiber enters the coating apparatus. The cooling means comprises an elongated coolant tube through which the fiber passes. Cool dry helium is flowed into that end of the coolant tube into which the fiber enters. In a preferred embodiment, the coolant tube is surrounding by a chamber containing a liquified gas. The helium is cooled by flowing through a coil submerged in the liquified gas prior to being flowed into the tube. An iris diaphragm located at the fiber input end of the coolant tube prevents the entry of moist, warm air into that tube.

Abstract: Various CVD processes are known whereby glass particles are flowed toward or over a substrate on which they are to be deposited. Because the substrate is cooler than the stream in which the particles are flowing, the thermophoretic force directs the particles toward the substrate. In accordance with the invention a beam of laser light is propagated over the surface in the vicinity of the stream of particles. The particles and/or a component within the stream absorbs the laser energy to induce within the stream of particles a temperature gradient whereby temperature increases with increased distance from the substrate surface.

Abstract: A plurality of photo sensitive devices arranged in vertical orientation monitors the sag of a loop of optical fiber extending between a feed capstan and a take-up spool. Each detector is connected to a respective switching circuit which, when activated by the presence of the fiber adjacent to its associated detector, generates a unique voltage. The switching circuits are connected to a motor control circuit by a sample and hold circuit which supplies to the motor control circuit a voltage proportional to the voltage generated by the most recently activated switching circuit. The speed of the motor driving the take-up spool is thus adjusted to cause the fiber catenary to return to a predetermined position.

Abstract: A process for manufacturing a preform from which is drawn an optical fiber, the core of which comprises layers of different glass composition. Layers of glass soot are deposited on the flat, longitudinally extending sides of a thin, elongated mandrel. Adjacent soot coatings have different refractive indices. A preliminary coating of cladding glass soot is deposited on the laminated soot structure. The resultant composite body is consolidated and stretched to form a rod or core structure upon which the final coating of cladding soot is deposited. The resultant composite body is consolidated and drawn into an optical fiber. In a modification of the this method, the mandrel is removed after the planar soot coatings and preliminary coating of cladding soot are deposited thereon. The resultant soot body is consolidated and processed as described previously.

Abstract: Porous glass optical fiber preforms are conventionally formed by depositing many layers of glass soot on a mandrel, removing the mandrel, and heating the porous preform to form a consolidated glass article. To prevent the formation of a devitrified layer at the aperture-forming surface during the consolidation step, the rate of soot deposition is initially reduced so that a stratum of fine soot is initially deposited on the mandrel. The stratum is initially discontinuous, but after a plurality passes of the soot-producing burner, it becomes continuous. Thereafter, the formation of the remainder of the soot preform continues in a conventional manner.

Abstract: A single mode optical waveguide is fabricated in a manner such that the core thereof is subjected to a stress-induced birefringence. This characteristic is accomplished by introducing into the cladding region of the fiber on opposite sides of the core longitudinally extending regions of glass having a thermal coefficient of expansion different from that of the remainder of the cladding. A number of novel techniques are disclosed for forming such a fiber.

Abstract: A monolithic capacitor chip having improved conductive terminations. The capacitor comprises a conventional body formed of stacked, alternately arranged layers of dielectric material and metallic electrode material, alternate electrodes extending to opposite endfaces of the body, and a noncompliant metalized layer on each of the opposite endfaces electrically contacting the electrodes extending thereto. In accordance with this invention each of the noncompliant metalized layers is provided with a compliant coating of an alloy preferably comprising more than 90% lead. A metallic layer is disposed over the surface of each of the compliant coatings, the melting point of the metallic layers being greater than that of the compliant coating. The metallic layer preferably consists of a layer of copper or nickel plating, the surface of which is plated with an oxidation resistant metal such as tin, gold, or the like.

Abstract: A glass optical waveguide preform is formed by depositing first and second coatings of glass soot on a mandrel. The characteristics of the first coating are such that it can ultimately form the core of an optical fiber. The core-clad diameter ratio of the preform is greater than that necessary to provide the desired core-clad diameter ratio of the resultant fiber. The mandrel is removed and the porous preform is consolidated. The preform aperture is etched, rinsed and dried. One end of the preform is heated and pinched to close the aperture. The aperture is evacuated, and the remaining end of the preform is heated, the corresponding end of the aperture being caused to close. An intermediate fiber is drawn from the resultant consolidated preform, the entire aperture being closed during drawing due to the low pressure within the aperture. The intermediate fiber is severed into sections, each of which functions as a mandrel for the deposition of a further coating of cladding soot.

Abstract: A plurality of controlled devices are connected to a controller in such a manner that the first device is connected by a cable to the controller, the second device is connected by a cable to the first device and so on. Interconnection means at each controlled device, which connects the cable from the previous device to the cable connected to the next device, automatically assigns a unit address to each device depending upon the position of that device in the chain of devices. Thus, if four devices are connected in a chain to the controller, their addresses are 1, 2, 3 and 4, beginning with the first unit connected to the controller and ending with the last unit in the chain of devices.

Abstract: Disclosed is an optical waveguide fiber coating system having means for cooling the hot fiber prior to the time that the fiber enters the coating apparatus. The cooling means comprises an elongated tube through which the fiber passes. Cool dry helium is flowed from a porous member or an annular slot surrounding said fiber so that it has a flow component directed radially inwardly toward said fiber and a flow component which is directed longitudinally toward the opposite end of the tube.

Abstract: A portion of a collimated light beam is directed at an article, and the resultant shadow-containing beam is reflected by a mirror onto a linear photodiode array. A second portion of the collimated beam is initially reflected by the mirror toward the article. The resultant shadow-containing beam impinges upon a second portion of the diode array. The positions of the two shadows on the array are indicative of the X and Y positions of the article. The scanned output from the array is processed to generate two binary signals representative of the X and Y positions.

Abstract: A single mode optical waveguide is constructed in a manner such that the core thereof is subjected to a stress-induced birefringence. The fiber comprises an oblong core surrounded by an oblong inner cladding layer. An outer layer of stress cladding glass, which has a circular outer surface, surrounds the inner cladding layer. The TCE of the stress cladding glass is different from that of the inner cladding glass.

Abstract: Solid glass articles are made by the flame hydrolysis technique. A thin stratum of low viscosity glass soot is applied to the surface of a mandrel. First and second coatings of glass soot are deposited on the surface of the thin stratum to form a porous preform. The refractive index of the soot particles of the first coating is greater than that of the soot of the second coating, and the soot of the first coating has a viscosity lower than that of the second coating. The mandrel is removed, and the soot preform is subjected to a high temperature whereby it is consolidated to form a dense glass blank. The glass surface tension and the relative viscosities of the inner and outer portions of the preform cause the aperture to close during the consolidation process. The thin stratum, which preferably includes P.sub.2 O.sub.5, smoothes over the damage caused by removing the mandrel and reduces or even eliminates seed formation at the axis of the resultant glass blank.

Abstract: Disclosed are a method and apparatus for improving the fatigue characteristics of a glass optical waveguide fiber. After the fiber is drawn and before it is provided with a protective coating it is heated to a temperature within the annealing temperature range. A filtered gas may be flowed over the fiber during the step of heating.

Abstract: A method of making a glass optical fiber having a core surrounded by cladding containing diametrically opposed regions of different TCE than the cladding. Three manufacturing techniques are disclosed. (1) A first glass rod having core and cladding glass is placed centrally in a glass tube. Rods of glass having a TCE different from that of the cladding glass are put on opposite sides of the first rod. Rods of cladding glass are placed in the interstices. (2) A soot preform is deposited on a rotating mandrel. In one embodiment, mandrel rotation is halted to deposit one longitudinally extending region and then rotated 180.degree. to deposit the other such region. In a modified embodiment the mandrel continuously rotates and the deposition burner is continuously supplied with reactant gas for forming a base glass and is also provided with pulses of a reactant gas for modifying the base glass to form the diametrically opposed regions.