Abstract: A fiber (106) having low polarization mode dispersion is made by heating the end of a preform (100) with a furnace (101). The fiber is drawn from the heated end. The fiber passes between two rollers (102, 104). As the fiber passes therebetween, the angular tilt of each of the rollers is changed so that a spin is imparted to the fiber.

Abstract: Optical fiber is provided with a periodically reversing spin while the fiber is pulled through a melt zone. A cooled region of the fiber downstream from the melt zone passes between a pair of opposed elements. The opposed elements are moved so that surface regions engaging the fiber move in opposite lateral directions relative to one another, thus spinning the fiber about its axis. The lateral movement of the engaged surface portions is periodically reversed to reverse the spin direction. The opposed elements may include belts or rollers, which can be tilted to orientations oblique to the longitudinal direction of the fiber.

Abstract: Disclosed is a single mode optical waveguide fiber having a core region refractive index profile designed to provide a highly non-linear refractive index. The core index profile of the highly non-linear waveguide is an &agr;-profile which has pre-selected values of relative refractive-index and core diameter so as to retain the advantageous optical waveguide properties of low attenuation, properly placed zero dispersion and cut off wavelengths, low, positive total dispersion over a pre-selected wavelength range, and low dispersion slope.

Abstract: Optical fiber is provided with a periodically reversing spin while the fiber is pulled through a melt zone. A cooled region of the fiber downstream from the melt zone passes between a pair of opposed elements. The opposed elements are moved so that surface regions engaging the fiber move in opposite lateral directions relative to one another, thus spinning the fiber about its axis. The lateral movement of the engaged surface portions is periodically reversed to reverse the spin direction. The opposed elements may include belts or rollers, which can be tilted to orientations oblique to the longitudinal direction of the fiber.

Abstract: Optical fiber is provided with a periodically reversing spin while the fiber is pulled through a melt zone. A cooled region of the fiber downstream from the melt zone passes between a pair of opposed elements. The opposed elements are moved so that surface regions engaging the fiber move in opposite lateral directions relative to one another, thus spinning the fiber about its axis. The lateral movement of the engaged surface portions is periodically reversed to reverse the spin direction. The opposed elements may include belts or rollers, which can be tilted to orientations oblique to the longitudinal direction of the fiber.

Abstract: A single-mode elliptical core optical fiber (15) suitable for the transmission of solitons has a core aspect ratio that changes along the length of the fiber to provide a fiber dispersion that monotonically decreases along the fiber from one end thereof to the other. The fiber preform (30) is drawn from a draw blank (10) having a glass core (11) surrounded by cladding glass (12) and having apertures (13) that are diametrically opposed with respect to the core (11). The cross-sectional area of the void space within the apertures (13) varies with respect to the longitudinal distance along the apertures.

Abstract: Disclosed is a method of making a polarization retaining single-mode optical fiber. Longitudinal grooves are formed on opposite sides of a cylindrically-shaped core perform having a glass core surrounded by cladding glass. The core preform is inserted into a glass tube, the tube is shrunk onto the core preform, and the interface between the core preform and the tube is fused to form a solid preform having longitudinal apertures on opposite sides of the core. An etchant gas is flowed through the apertures to enlarge the apertures into holes having a substantially round cross-section. Inserted into each aperture is a stress rod formed of glass having a coefficient of expansion different from that of the cladding glass. The resultant draw blank is drawn to form a single-mode optical fiber having a core that is subjected to a stress-induced birefringence.

Abstract: Disclosed is a method of making a polarization retaining single-mode optical fiber. There is initially formed a draw blank having diametrically opposed longitudinal apertures in the cladding glass parallel to the core glass region. The draw blank is drawn into a fiber under such conditions that the apertures close as the fiber is being drawn. The flow of surrounding glass, including the core glass region, toward the collapsing apertures, causes the core to assume an elliptical shape. The apertures are of such cross-sectional area and spacing from the core that the core develops the desired aspect ratio.

Abstract: The disclosed fiber optic filter structure includes an optical fiber having a single-mode core surrounded by cladding material, and at least one light-attenuating light path in the cladding material uniformly spaced from the single-mode core. The propagation constants of the single-mode core and the light path are different at wavelengths except for at least one wavelength .lambda..sub.4. The spacing between the single-mode core and the light path are sufficiently small that light within a first band of wavelengths centered around .lambda..sub.f couples between the single-mode core and the light path. At least a portion of the light within the first band of wavelengths is absorbed in the light path. In that embodiment in which the single-mode core is a fiber amplifier gain core, the filtering function of the light path modifies the fiber amplifier gain spectrum.

Abstract: This invention relates to a method of drawing twist-free optical fibers; it is particularly useful for drawing polarization retaining single-mode optical fibers having azimuthal inhomogeneities. There is applied to the fiber, during the drawing thereof, a coating having a non-circular cross-section, the azimuthal inhomogeneity of the fiber being positioned in a substantially constant orientation with respect to the non-circular cross-section of the coating. In another embodiment, a plurality of fibers having azimuthal inhomogeneities are drawn from a plurality of preforms that are properly oriented in the draw furnace. The fibers are drawn through the same coater so that the azimuthal inhomogeneity of each fiber is oriented in a substantially constant relationship with respect to the azimuthal inhomogeneities of the remaining fibers in the coating.

Abstract: A method of making a polarization retaining single-mode (PRSM) optical fiber coupler. A section of coating is stripped from the central portion of two PRSM optical fibers. The fibers extend through the bore of a glass tube, the stripped portions being centered in the tube, and the coating portions extending into the ends of the bore. In one embodiment, each fiber is provided with a rectangularly shaped coating, and the two larger flattened sides of the coating are specifically oriented with respect to the major and minor axes of the PRSM fiber therein. The fiber coating can be disposed in only one orientation in the rectangularly-shaped tube bore, thereby properly orienting the two PRSM fibers with respect to each other. In another embodiment, the PRSM fibers are disposed within a single coating, the azimuthal inhomogenity of one fiber being aligned in the coating with respect to that of the remaining fibers.

Abstract: A coupler is disclosed for properly positioning the endface of an optical waveguide filament with respect to an optoelectronic device in a repeatable fashion. Three elongated rods of deformable material are disposed in mutually contacting relationship within a bore which terminates at the device. After a filament is inserted into the aperture between the rods so that its endface is disposed adjacent to the device, an elastomeric washer is caused to deform inwardly against the rods, thereby causing them to engage the filament. Since the ends of the rods adjacent to the device are secured in the bore, the filament may be replaced by other filaments, the endfaces of which will be precisely positioned with respect to the optoelectronic device.

Abstract: A coupler for coupling an optical signal progagating in any one of a plurality of optical waveguide filaments to all of the remaining filaments. The coupler comprises a plurality of optical waveguide filaments, the end portions of which are fused together to form a unitary structure in which the filament cores are separated by only the filament cladding material. The end of the unitary structure is planar and is perpendicular to the axes of filament cores at the ends thereof. The end of the unitary structure is coated with a light reflecting material.

Abstract: An optical fiber connector comprising a first resilient member having elongated grooves in the surface thereof into which fibers to be optically connected are disposed end-to-end. A second resilient member is urged against that portion of the fibers opposite the first member, thereby causing a slight deformation of the second member and the groove forming walls. The substantial equilibrium of forces applied to each pair of fibers by the resilient members causes their axes to become aligned. A longitudinal force applied to each fiber urges the endface thereof into contact with the endface of the fiber that is to be connected thereto.

Abstract: An optical fiber connector comprising a first resilient member having an elongated V-shaped groove in the surface thereof into which two fibers to be optically connected are disposed end-to-end. A second resilient member is urged against that portion of the fibers opposite the first member, thereby causing a slight deformation of the second member and the slot-forming walls. The substantial equilibrium of forces applied to the two fibers by the resilient members causes their axes to become aligned. The preferred embodiment is capable of connecting corresponding fibers of two bundles and also includes means for positioning the endfaces of the fibers of one bundle in virtual contact with the endfaces of the fibers of the other bundle.

Abstract: An apparatus for severing the ends of a plurality of parallel optical fibers so that the endfaces thereof are relatively flat, are substantially perpendicular to the fiber axes and are relatively coplanar. The fibers are bent over an arcuate surface and are slidably clamped between the flat surfaces of two pieces of rubbery material. The clamp is urged by a spring in such a direction that the fibers are in tension. After one fiber is scored and breaks, the clamp automatically slides along the remaining fibers until the clamping force on those fibers is sufficient to prevent further sliding. The fibers are individually severed in this manner.