Abstract: A dispersion slope compensating optical waveguide, such as a fiber, having a high negative dispersion slope is provided. The optical waveguide comprises a core region and an clad layer. The core region further comprises a first region and a second region surrounding the first region. The width of the second region is sufficient to confine electromagnetic radiation within a selected wavelength range to substantially only the core region. Thus, bending loss in the waveguide is substantially reduced. The negative dispersion slope of the dispersion slope compensating optical waveguide can be used in conjunction with a dispersion compensating optical waveguide as a dual optical waveguide to compensate both the dispersion and dispersion slope of a transmission waveguide. An optical span and an optical transmission system incorporating the dual optical waveguide is also provided.

Abstract: An apparatus for proof testing an optical waveguide fiber includes a first capstan defining a first outer diameter and a continuous first capstan belt under tension and in contact with the first outer diameter of the first capstan. The contact between the first capstan belt and the first capstan defining a first arc of contact, and the first capstan belt defining a first width, a first thickness and a first length. The apparatus further includes a second capstan defining a second outer diameter and a continuous second capstan belt under tension and in contact with the outer diameter of the second capstan. The contact between the second capstan belt and the second capstan defining a second arc of contact, second capstan belt defining a second width, second thickness and a second belt length. The first arc of contact being equal to or greater than about 105° and the second arc of contact being at least 20° greater than the first arc of contact.

Abstract: Disclosed is a dispersion compensating and dispersion slope compensating single mode optical waveguide fiber. The refractive index profiles of waveguide fibers in accord with the invention are disclosed and described. These index profiles provide a waveguide fiber having negative total dispersion and negative total dispersion slope so that a standard waveguide fiber is compensated over an extended wavelength range. A telecommunications link using the fiber in accord with the invention is also disclosed and described. A standard fiber to compensating fiber length ratio in the range of 1:1 to 3:1 is shown to give optimum link performance with respect to limiting non-linear dispersion effects.

Abstract: A method and apparatus for measuring the pulse width of a narrow optical pulse, particularly in a multi-mode optical fiber. A spectrograph and streak camera are combined to record optical intensity data in a 2-dimensional array resolving both wavelength and temporal dependence of the optical pulse. The data is analyzed to calculate the chromatic dispersion and then to remove it. For example, the data in different wavelength windows are time shifted relative to each other by the amount of the chromatic dispersion so that all windows have approximately the same temporal dependence. The correction may numerically establish time offsets producing the maximum cross-correlation between wavelength windows. The corrected data may then be summed over optical wavelength, and the corrected time-dependent data is further analyzed to establish optical pulse width and impulse response of the fiber. Thereby, a laser diode with relatively large spectral width can characterize a high-bandwidth fiber.

Abstract: The present invention provides an optical fiber, comprising a core having an alpha parameter in the range of approximately 2 to approximately 8, a maximum index percent difference between the core and a cladding in the range of approximately 0.3% to approximately 0.5% and a core diameter in the range of approximately 6.0 to approximately 16.0 &mgr;m and a cladding. The optical fiber has a bandwidth of at least approximately 0.6 GHz.km at 850 nm, and is configured for multimode operation at a wavelength less than 1300 nm and single mode operation at a wavelength of at least approximately 1300 nm. The fiber also has significantly reduced intermodal noise. The present invention also includes a method of designing such a fiber, a fiber optic system provided such a fiber and a method of operating a fiber optic system with such a fiber.

Abstract: Disclosed is an optical waveguide fiber preform and an optical waveguide fiber drawn therefrom, in which the density and thus the effective refractive index of the clad layer is caused to change in a pre-selected way axially along the waveguide preform and the associated waveguide fiber. The axial change in density of the clad layer is due to the fraction of the clad volume that is air or a glass of a composition different from that of the base clad glass. The axially variation in clad index changes the signal mode power distribution, thereby changing key waveguide fiber parameters such as magnitude and sign of dispersion, cut off wavelength and zero dispersion wavelength. The invention includes methods of making the structures having an axially varying clad layer. The invention relates to preforms and associated waveguide fibers which guide light due to difference in refractive index between core and clad.

Abstract: Disclosed is a photonic band-gap crystal waveguide having the physical dimension of the photonic crystal lattice and the size of the defect selected to provide for optimum mode power confinement to the defect. The defect has a boundary which has a characteristic numerical value associated with it. The ratio of this numerical value to the pitch of the photonic crystal is selected to avoid surface modes found to exist in certain configurations of the photonic band-gap crystal waveguide. Embodiments in accord with the invention having circular and hexagonal defect cross sections are disclosed and described. A method of making the photonic band-gap crystal waveguide is also disclosed and described.

Abstract: Disclosed is a single mode waveguide fiber and a method of making a single mode or multimode waveguide fiber which has an azimuthally and radially asymmetric core. This asymmetry provides additional degrees of freedom for use in forming a waveguide having particular performance characteristics.

Abstract: Disclosed is a multiple core optical waveguide fiber having a negative total dispersion and negative total dispersion slope tailored to compensate the total dispersion of a typical high performance transmission fiber over a selected wavelength range. Also disclosed is a method of making the multiple core optical waveguide fiber and a compensated link using the multiple core fiber. The simplicity of the refractive index profiles of the constituent cores provides ease of manufacture of the multiple core structure.

Abstract: Disclosed is a dispersion compensating and dispersion slope compensating single mode optical waveguide fiber. The refractive index profiles of waveguide fibers in accord with the invention are disclosed and described. These index profiles provide a waveguide fiber having negative total dispersion and negative total dispersion slope so that a standard waveguide fiber is compensated over an extended wavelength range. A telecommunications link using the fiber in accord with the invention is also disclosed and described. A standard fiber to compensating fiber length ratio in the range of 1:1 to 3:1 is shown to give optimum link performance with respect to limiting non-linear dispersion effects.

Abstract: An optical waveguide fiber having a thin carbon coat over the clad glass layer is disclosed. The carbon coated waveguide shows superior dynamic fatigue resistance, improved adhesion of a polymer overcoat in environmental testing, excellent attenuation stability in environmental testing, and easy colorability.

Abstract: Disclosed is a dispersion shifted optical waveguide fiber having low but non-zero dispersion over an extended wavelength window that includes wavelengths, from 1470 nm to 1625 nm. Waveguide fiber core refractive index profiles exhibit the desired dispersion performance while maintaining resistance to pin array and lateral load bending at least equivalent to standard waveguide fiber. Attenuation over the operating wavelength range is low and zero dispersion wavelength is typically less than 1450 nm.

Abstract: Disclosed is a telecommunications system link that includes plurality of spans each having a transmission fiber and a compensating fiber. The compensating fiber is selected to completely compensate dispersion slope while only partially compensating total dispersion. This configuration compensates dispersion over an operating wavelength range while at the same time providing a transmission path having non-zero dispersion.

Abstract: Disclosed is a single mode optical waveguide fiber having a segmented core in which the central segment is a void. The shape and radial extent of the core segments are selected to provide a low dispersion slope together with large effective area and good bend resistance. Embodiments of the refractive index profiles in accord with the invention are shown having two or three annular segments surrounding the central void. The presence of the void provides the benefits of a negative relative index located centrally in the core region without the process difficulties associated with the use of dopants that decrease the refractive index of the waveguide fiber.

Abstract: A single mode optical waveguide fiber having a relatively large effective area and a low dispersion slope has a segmented core having a central segment, a first annular segment, and a second annular segment. Each segment has a relative refractive index percent, and an inner and outer radius. The relative refractive index percent and the radii of each core segment are chosen from the following ranges: the relative index of the central segment within the range of about 0.53% to about 0.9%; the relative index of the first annular segment within the range of about −0.2% to about 0.15%; the relative index of the second annular segment within the range of about 0.1% to about 0.4%; the outer radius of the central segment within the range of about 3.1 &mgr;m and about 5.0 &mgr;m; and the center radius of the third annular segment within the range of about 6.18 &mgr;m and about 7.7 &mgr;m.

Abstract: Disclosed is a method of making a photonic crystal preform which provides improved properties of the photonic band-gap crystal waveguide fiber drawn therefrom. The photonic crystal preform defect is formed using materials having a particular shape or composition so that the defect walls are preferentially etched away to provide a photonic band-gap crystal waveguide fiber having a smooth walled defect.

Abstract: Dispersion managed fibers which preferably have a central core region, a moat region, and a ring region are provided. The central core region preferably has an alpha profile with an alpha value preferably less than about 2.3. The moat region preferably includes four sub-regions, namely, a first sub-region (11) in which the index of refraction decreases, a second sub-region (12) in which the index of refraction increases substantially linearly, a fourth sub-region (14) in which the index of refraction again increases substantially linearly, and a third sub-region (13) which serves as a transition region which smoothly connects the third and fourth substantially linear sub-regions.

Abstract: Disclosed is a single mode optical waveguide having a segmented core of at least two segments. The relative refractive index, the index profile and the radial dimensions of the core segments are selected to provide an optical waveguide fiber having properties suitable for a high performance telecommunication system operating in the wavelength window of about 1530 nm to 1570 nm. Embodiments of the invention having two, three and four segments are described.

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 Dw 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: Disclosed is a method of making a photonic crystal using a combination of extruding and drawing techniques. The method is contemplated as being capable of producing both two and three dimensional crystals due to the maturity and diversity of extruding and drawing technology. The method allows the drawing of relatively large photonic crystals and is flexible enough to provide a periodic array of channels or filaments as the crystal features. After the extruding step or steps and before the step of heating and drawing, a plurality of elongated extruded bodies can be bundled and drawn as a unit.