Abstract: A single mode optical waveguide having reduced polarization mode dispersion and a method for making such a waveguide is disclosed. Perturbations are introduced into the waveguide core to couple power between the two polarization modes. A model calculation shows that the perturbation length may be of the order of the correlation length. The inventive waveguide is robust in that polarization mode dispersion is reduced even if perturbations are impressed on the fiber after manufacture.

Abstract: Optical waveguide core compositions comprising a core containing two dopants in a silica based glass, wherein one of the dopants is titania. The core composition serves to suppress the presence of Ti.sup.-3 and to preserve refractive index profile shape throughout the preform manufacturing process.

Abstract: A single mode optical waveguide fiber having a segmented core designed to provide a large effective area for light transmission. The large effective area reduces waveguide fiber non-linearities. The inventive waveguide is thus suited for transmission of high power signals over long distances. Embodiments of the inventive single mode waveguide including five core segments are given. The large effective area is achieved with essentially no degradation in optical or mechanical performance of the waveguide.

Abstract: A method and apparatus for writing a Bragg grating in a photosensitive optical waveguide is disclosed. The novel method comprises an interferometer having precisely adjustable light collecting and directing components. A phase mask illuminated with ultraviolet light is used as the interferometer light source. The adjustability of the interferometer allows the writing of Bragg gratings for filtering wavelengths in the range 1275 nm to 1575 nm while adjusting the appropriate interferometer elements by only +/-0.75.degree. each.

Abstract: A device for assembling ends of optical fibers into a sheet. Each of the ends is stripped of any resilient coating and has a flat terminal face. A grooved substrate is supported on a cradle means. An adhesive dispensing means deposites adhesive into the grooves. A gripping means grips the optical fibers to form the ends into a sheet and positions each of the optical fibers into the grooves of the substrate. A portion of each of the optical fibers, including the ends, extends beyond an edge of the substrate. A means holds a plate, having a flat surface, against the substrate where the plate covers the grooves to hold the optical fibers in the grooves and where the plate bonds to the substrate. The flat surface extends beyond the edge of the substrate to cover the portion of each of the optical fibers extending beyond the edge of the substrate.

Abstract: An adhesive product ?9! in the liquid state is deposited in a plurality of parallel, rectilinear, and equidistant grooves ?6i! formed in a flat surface of a substrate ?5!; each of the stripped ends ?1i! of the fibers in the sheet is introduced into a corresponding groove ?6i!, and the ends of the fibers are held in the grooves with the aid of a plate ?13! affixed to these grooves. In accordance with the invention, because the adhesive product ?9! is still in the liquid state, the entire collection of the ends ?1i! of the fibers extending from the grooves ?6i! is pressed against a facing flat portion ?13'! of the plate ?13! extending from the substrate ?5!, and this pressure is maintained until the adhesive product ?9! hardens and the plate ?13! is glued.

Abstract: A single mode optical waveguide having large effective area is disclosed. The large effective area is achieved by using a segmented core profile design which includes at least one segment, or a part of one segment, having a refractive index less than the minimum refractive index of the clad layer. The large effective area serves to reduce or eliminate detrimental non-linear optical waveguide effects which limit regenerator spacing and bit rate. The large effective area is achieved while maintaining bend resistance at least as good as that of standard step index single mode waveguide fiber.

Abstract: A symmetric, dispersion-managed fiber optic cable in accordance with the present invention includes a first and a second optical fiber. The first optical fiber is a conventional single mode fiber (SMF) type fiber and has a first effective area and a positive dispersion characteristic at a predetermined operating wavelength range. The first optical fiber is split into two segments each having substantially the same length. The second optical fiber has a second effective area and a negative dispersion characteristic at the operating wavelength range. Typically, second optical fiber is a DSF or an NZD fiber, both with negative dispersion and a small effective area. The second optical fiber is coupled between the two segments of the first fiber to create a fiber optic cable with an average total dispersion at the operating wavelength range which is substantially zero. The fiber optic cable may be incorporated into an optical fiber transmission system with an optical terminal and at least one repeater.

Abstract: A single mode optical waveguide fiber having a positive total dispersion is disclosed. The novel waveguide fiber has a core region comprising three distinct segments. Studies of this novel waveguide, wherein properties are calculated as various ones of the core region parameters are changed, show that the waveguide satisfies the requirements of a fiber in a high bit rate, long regenerator spacing system. The novel waveguide design is relatively simple to manufacture and maintains its functional properties at tight tolerances when the core region parameters are varied over a prescribed range. This high performance waveguide limits self phase modulation and four wave mixing, facilitates wavelength division multiplexing, and is compatible with optical amplifiers.

Abstract: A radiation resistant optical waveguide fiber doped with fluorine or drawn with low tension in the fiber. The fluorine doping is substantially constant across the core and a portion of the clad adjacent the core. The concentration of the fluorine is in the range of about 0.3 to 3.0 weight percent. The draw tension is less than or equal to about 5 grams (40 dynes/cm.sup.2) to achieve optimum radiation resistance. A synergy is found when fluorine and low draw tension are applied to a fiber. Improvement in radiation resistance is largely independent of fiber type and geometry. Further improvement in radiation resistance is found when germanium is doped in a portion of the clad adjacent the core.

Abstract: A tradeoff between crosstalk and channel bandwidth in dense wavelength demultiplexers is achieved by varying mode fields of input and output waveguides. Funnels are formed between inner and outer ends of the input and output waveguides to increase mode field radii, which results in decreased crosstalk attenuation but larger bandwidth channels.

Abstract: An apparatus is provided for applying a tensile force along the longitudinal axis of a cane assembly during the deposition of soot thereon to produce an optical fiber preform. Fiber drawn from such a preform exhibits improved core/clad concentricity. The tensile force may be applied at one or both ends of the cane assembly, with application at both ends being preferred. The tensile force may be varied during the deposition of soot. The cane assembly may be annealed prior to beginning the deposition of soot thereon.

Abstract: A novel optical waveguide fiber having low total dispersion slope, relatively large mode field diameter, larger effective area, and a relatively simple core profile design is disclosed. The core refractive index profile comprises three segments. The adjustability of the height, width and location of the three core index profile segments, provides sufficient flexibility to meet a specification which calls for a dispersion shifted waveguide fiber capable of limiting four photon mixing or self phase modulation. The novel waveguide is characterized by a mode field diameter .gtoreq.7.5 microns and a total dispersion slope .ltoreq.0.070 ps/nm.sup.2 -km.

Abstract: An M.times.O multiplex/demultiplex device is disclosed. An M.times.N coupler is connected to an N.times.O coupler by phase shifting means. The phase shifting means provide N paths between the couplers, each path having an optical path length different from every other optical path length. The coupling region of the M.times.N coupler must provide for substantially uniform division of light power among the coupler branches when M are the launch ports. Similarly, the coupling region of the N.times.O coupler must provide for substantially uniform division of light power among the coupler branches when O are the launch ports. A preferred embodiment includes two fused waveguide fiber couplers with dissimilar waveguide fibers used as the phase shifting means.

Abstract: The present invention relates to an optical system for providing uniform illumination of a light valve. The light source is an extended source generally emitting a non-uniform spatial distribution of light power. Source light is focused into the entrance end of a light transmitting tunnel having reflecting interior wall surfaces and having cross sectional and length dimensions chosen to deliver, at the exit end of the tunnel, light which is substantially uniform in power distribution over the surface area of the exit end. This is caused by multiple reflections from the tunnel walls. The exiting light is advantageously used to illuminate uniformly a light valve. The tunnel may be tapered to alter the exit angular aperture. The tunnel may be hollow or filled with a transparent material. In addition, the tunnel may be segmented and folded to provide a joint which conforms tunnel geometry to given spatial limitations between source and valve.

Abstract: A single mode optical waveguide fiber designed for high data rate, or WDM systems or systems incorporating optical amplifiers. The optical waveguide has a compound core having a central region and at least one annular region surrounding the central region. A distinguishing feature of the waveguide core is that the minimum refractive index of the central core region is less than the minimum index of the adjacent annular region. A relatively simple profile design has the characteristics of ease in manufacturing together with, flexibility in tailoring D.sub.w to yield a preselected zero dispersion wavelength, dispersion magnitude over a target wavelength range, and dispersion slope. The simplicity of profile gives reduced polarization mode dispersion.

Abstract: A planar optical waveguide comprises a substrate 1, a waveguide core layer 2, at least one planar optical element, wherein said planar optical element comprises at least one optically functional interface 3 which is adjacent to a cavity 4, and an overclad layer 5. The cavity enhances the optical characteristics of the planar optical element because of the substantial difference in the refractive index of the cavity as compared to the refractive index of said waveguide core layer.

Abstract: Disclosed is a single mode optical waveguide fiber having periodic perturbations in the core to provide a birefringence which mixes the polarization modes of launched light. In addition, perturbations are introduced into the core which serve to manage total dispersion. The total dispersion of pre-selected segments of the waveguide are caused to change sign so that the sum of products, total dispersion times length, algebraically add to a pre-selected value. The two distinct core perturbation types serve to control both polarization mode dispersion and total dispersion. Methods for making the subject waveguide are also discussed.

Abstract: Polymeric compositions having a polymeric component and an inorganic filler which undergoes a crystal (phase) inversion within the operating temperature range of the composition are provided. The present invention relates to a method for reducing the water sensitivity of particles of a crystallized phosphate glass. The particles are composed of P.sub.2 O.sub.5 and one or more cations selected from the group consisting of magnesium, cobalt, arsenic, zinc, iron, aluminum, and zirconium. The method includes nitriding the particles.

Abstract: An image projection system wherein light provided from a source passes through a prism and is then incident on an array of reflecting elements which are individually adjustable between a first and second position. Light reflected from each element re-enters the prism. Light from elements in the first position pass through the prism and into a lens. Light from elements in the second position travel through the prism, but do not enter the lens. The principal plane of the lens and the plane in which the elements are located are each parallel to the adjacent surface of the prism.