Abstract: Disclosed is a family of dispersion compensating optical fibers that are adapted for use with conventional single-mode transmission fibers that are optimized for zero dispersion operation at a wavelength in the range from 1290 nm to 1330 nm to form a transmission link suitable for low dispersion operation in the 1520-1565 nm wavelength window. The dispersion compensating fibers are capable of providing a dispersion more negative than -20 ps/nm-km and attenuation less than 1 dB/km at wavelengths in the 1520-1565 nm region. Certain of the dispersion compensating fibers also exhibit a dispersion versus wavelength relationship having a negative slope in the 1520-1565 nm region, to compensate for the dispersion versus wavelength slope of the transmission fiber. The dispersion compensating fiber can be advantageously combined with a fiber amplifier to form a compensator that is adapted to overcome attenuation introduced into the system by the dispersion compensating fiber.

Abstract: A vapor deposition method for making preforms from which optical waveguide fibers are drawn wherein at least a first precursor compound is oxidized at one oxidation site and at least a second precursor compound, which is different from the first precursor compound, is oxidized at a second oxidation site. The method is particularly applicable in cases where the first and second precursor compounds are chemically incompatible with one another or where the flow rate of the second precursor compound is substantially lower than the flow rate of the first precursor compound.

Abstract: An optical waveguide fiber with a fatigue resistant TiO.sub.2 -SiO.sub.2 outer cladding including a cylindrical outermost layer with TiO.sub.2 concentration greater than 10.5 wt. % and thickness less than 3 .mu.m. The fiber may include a two layer outer cladding with higher TiO.sub.2 concentration in the outer layer. The outer cladding may include a plurality of inhomogeneities dispersed in a TiO.sub.2 -SiO.sub.2 matrix.

Abstract: An optical fiber is drawn from a draw blank that is situated in a furnace muffle. An end of the blank is heated to a temperature sufficient to permit a fiber to be drawn therefrom. During the fiber drawing operation, the blank is subjected to a gas containing an amount of hydrogen sufficient to reduce the number of defects in the fiber. The resultant fiber therefore experiences little or no latent attenuation increase when it is later subjected to a hydrogen containing atmosphere.

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 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.

Abstract: A single mode optical waveguide is fabricated in a manner such that the core thereof is subjected to a stress-induced birefringence. A hollow intermediate product is formed by depositing layers of cladding and core glass on the inner surface of a substrate tube. Opposite sides of the intermediate product are heated to cause it to collapse into a solid preform foreproduct having an oblong cross-section. A layer of flame hydrolysis-produced soot having a circular outer surface is deposited on the preform foreproduct and is consolidated to form a dense glass cladding layer thereon. The TCE of the outer cladding layer is different from that of the preform foreproduct on which it is deposited so that when the resultant preform is drawn into a fiber, a stress-induced birefringence exists in the core.

Abstract: A process for making a tubular optical waveguide preform for a high-numerical-aperture optical waveguide which comprises an inner compression layer for enhanced preform strength, and a soot preform produced in accordance with the process, are described.

Abstract: A method for delivering vaporous source materials to an oxidizing reaction flame or the like. Each constituent is maintained in liquified form in an enclosed container that is provided with a heater for raising the temperature of the liquid to a value sufficient to provide a predetermined vapor pressure within the reservoir. The resultant vapors are transferred by means of individually controlled metering means and appropriate conduits to the reaction device. Oxygen may be added to the vapor conveying conduit or directly to the vapor utilization device.

Abstract: A substantially continuous method of and apparatus for forming an article suitable for an optical waveguide preform wherein the starting member is continuously removed is disclosed. The preform is formed by providing a starting member or bait and applying the particulate material to the exterior surface of the starting member to form a coating thereon. The coating is longitudinally translated while simultaneously additional particulate material is applied to the coating to form a preform body with the preform body thereafter being longitudinally translated. While longitudinally translating the preform body and applying additional particulate material to the end thereof, the starting member is continuously removed from the preform body leaving a longitudinal aperture remaining in the preform body. The particulate material may be applied by one or more burners, the output of which may be controlled to provide a predetermined desired cross sectional composition variation of the resulting preform body.

Abstract: A method of making solid glass articles by the flame hydrolysis technique. First and second layers of glass soot produced by a flame hydrolysis are deposited on the outside surface of a mandrel to form a porous preform. The refractive index of the soot particles of the first layer is greater than that of the soot of the second layer, and the soot of the first layer has a viscosity lower than that of the second layer. 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 resultant blank may be heated and drawn into a filament, or it may be sliced into optical windows, lenses or the like.CROSS-REFERENCE TO RELATED APPLICATIONThis is a continuation of application Ser. No. 922,559, filed July 7, 1978, which is a continuation-in-part application of U.S.

Abstract: A system for delivering a siliceous matrix material and selected dopants to an oxidizing reaction flame or the like. Each constituent is maintained in liquified form and transferred by means of an individually controlled metering pump to a nebulizing stage then passed to a burner or the like from which the materials are converted into appropriate soots. The soots are then applied to a starting member which is subsequently subjected to heat to fuse it into a drawing blank.

Abstract: A system for delivering a siliceous matrix material and selected dopants to an oxidizing reaction flame or the like. Each constituent is maintained in liquified form and transferred by means of an individually controlled metering pump to a nebulizing stage then passed to a burner or the like from which the materials are converted into appropriate soots. The soots are then applied to a starting member which is subsequently subjected to heat to fuse it into a drawing blank.

Abstract: A method of forming an optical waveguide by forming a first layer of glass having a predetermined refractive index on the outside peripheral wall surface of a substantially cylindrical mandrel. Thereafter, a second layer of glass is applied to the surface of the first layer, the second layer having a refractive index less than that of the first layer. The mandrel is removed from the assembly and the resultant cylindrical, hollow assembly is heated and drawn to reduce the cross-sectional area thereof, thereby forming an intermediate fiber. At least a portion of the intermediate fiber is disposed within a hollow glass cylinder having a refractive index similar to that of the second layer of glass of the intermediate fiber.