Abstract: A dispersion compensating optical fiber for use in a high data rate telecommunications span or link. The dispersion compensating optical fiber in accordance with the invention provides excellent compensation of total dispersion over a range of wavelengths (e.g., 1527–1567 nm), thus minimizing signal distortion in wavelength division multiplexed systems. The dispersion compensating fiber has a refractive index profile with a central core segment having an inner peak with ?i%, an outer peak with ?1%, and a trough with a ?t% less than both ?i% and ?1%, a moat segment with a ?2%, and a ring segment with a ?3%. Preferably, ?t% and ?3% are greater than ?2%. Also disclosed is an optical transmission span having residual dispersion less than +/?25 ps/km for 100 km of transmission fiber over a wavelength band of 1527–1567 nm.

Abstract: An aluminum titanate-based ceramic article having a composition comprising u (Al2O3—TiO2)+v (R)+w (3Al2O3—2SiO2)+x (Al2O3)+y (SiO2)+z (1.1SrO-1.5Al2O3-13.6SiO2—TiO2)+a (Fe2O3—TiO2)+b (MgO-2TiO2), where, R is SrO—Al2O3-2SiO2 or 11.2SrO-10.9Al2O3-24.1SiO2—TiO2, where u, v, w, x, y, z, a and b are weight fractions of each component such that (u+v+w+x+y+z+a+b=1), and 0.5<u?0.95, 0.01<v?0.5, 0.01<w?0.5, 0?x?0.5, 0?y?0.1, 0?z?0.5, 0<a?0.3, and 0?b?0.3. A method of forming the ceramic article is provided. The ceramic article is useful in automotive emissions control systems, such as diesel exhaust filtration.

Abstract: An extrusion apparatus which satisfactorily adjusts differences in skin-body flow rates at multiple locations around the die, and allows for the external manipulation of the interior components controlling batch flow, during the production without having to stop manufacturing operations to effect the necessary changes thereat.

Abstract: A dispersion compensation fiber for a moderate dispersion, low slope transmission fiber and transmission system including same. The dispersion compensating fiber has a refractive index profile having a central core with a core delta (?1), a moat surrounding the central core having a moat delta (?2), and a ring surrounding the moat having a positive ring delta (?3). The fiber's refractive index profile is selected to provide total dispersion less than ?80 at 1550 nm and less than ?90 ps/nm/km at 1600 nm, dispersion slope less than ?0.18 ps/nm2/km at 1550 and less than ?0.10 ps/nm2/km at 1600 nm/kappa between 250 and 450 at 1550 nm, and a kappa ratio (defined as kappa at 1600 nm/kappa at 1550 nm) of greater than 1.35.

Abstract: A dispersion compensating optical fiber includes a segmented core having a central core segment, a moat segment and a ring segment. The refractive index profile is selected to provide a total dispersion at 1550 nm of between ?114 and ?143 ps/nm/km, and a kappa, defined as the total dispersion at 1550 nm divided by the dispersion slope at 1550 nm, of between 96 and 150 nm. Optical transmission systems including the present invention dispersion compensating optical fiber optically coupled to a moderate dispersion single mode transmission fiber having dispersion at 1550 nm of between 5 and 14 ps/nm/km are also disclosed. Example transmission systems preferably exhibit residual dispersion over the C+L wavelength band (1525 to 1625 nm) of less than +/?20 ps/nm per 100 km of the moderate dispersion transmission fiber and less than +/?10 ps/nm per 100 km of the moderate dispersion transmission fiber over the C band (1525 to 1565 nm).

Abstract: A Dispersion Compensation (DC) fiber for low slope transmission fiber (such as a NZDSF) and transmission line including same. The DC fiber has a refractive index profile having a central core with a core delta (?1) value less than 1.8%, a moat surrounding the central core having a moat delta (?2) value greater than ?0.9%, and a ring surrounding the moat having a positive ring delta (?3). The DC fiber's refractive index profile is selected to provide total dispersion less than ?40 and greater than ?87 ps/nm/km, and kappa of greater than 165 and less than 270 nm, all at 1550 nm. The DC fiber, when used in a transmission line, may provide low average residual dispersion across the C, L, and C+L when such lines include transmission fibers with a total dispersion between 4 and 10 ps/nm/km and a dispersion slope less than 0.045 ps/nm2/km at 1550 nm.

Abstract: A DCF adapted to compensate for dispersion and slope of a length of SMF in the C-band window that includes a core surrounded by a cladding layer of refractive index ?c. The core includes at least three radially adjacent segments, a central core segment having a positive ?1, a moat segment having a negative refractive index ?2, and a ring segment having a positive refractive index ?3, wherein ?1>?3>?c>?2. The DCF exhibits a negative Dispersion Slope (DS), where ?0.29 (ps/nm2·km) at 1546 nm, a dispersion (D), where ?100<D<?120 (ps.nm·km) at 1546 nm, and a ? value (D/DS) at 1546 nm that is preferably between 250 and 387 nm. The DCF preferably has a cutoff wavelength (?c) less than 1500 nm, attenuation at 1550 nm of less than 0.6 dB/km, and a bend loss of less than 0.01 dB/m on a 40 mm mandrel at 1550 nm. A transmission link including the combination of a SMF and a DCF having a dispersion (D), where ?100<D<?120, is also disclosed.

Abstract: A method and system for determining strain impressed on an optical fiber at a possibly indeterminate temperature. The fiber (14) is formed with at least two sensors having different strain and temperature characteristics, preferably a Bragg Fabry-Perot sensor having a Fabry-Perot cavity (16) formed between two like Bragg gratings (10, 12) and another Bragg grating 18 of a different pitch written into the Fabry-Perot cavity. Many such pairs can be written if the Bragg gratings reflect in different bands. The fiber is irradiated with broadband light, and the reflection is spectrally separated to produce separate spectra for all sensors. Wavelength shifts from two types of sensors can be correlated with strain and temperature according to predetermined variations of the shifts with known strain and temperature changes.

Abstract: A dispersion compensating optical fiber that includes a segmented core having a central core segment, a moat segment, and a ring segment wherein the ring segment is preferably offset from the moat outer radius, r2, by a ring offset, Xo, greater than 0.4 ?m. The refractive index profile is selected to provide a total dispersion at 1550 nm of between about ?120 and ?145 ps/nm/km, and a total dispersion slope at 1550 nm of between about ?0.36 and ?0.56 ps/nm2/km. The refractive index profile is preferably further selected to provide a kappa, defined as the total dispersion at 1550 nm divided by the dispersion slope at 1550 nm, of between about 250 and 320 nm. Optical transmission systems including the present invention dispersion compensating optical fiber which have residual dispersion less than +/?15 ps/nm per 100 km of standard single mode transmission fiber are also disclosed.

Abstract: A DCF for compensating for the accumulated dispersion of a length of SMF in the C+L band window that includes a core surrounded by a cladding layer of refractive index ?c. The core includes at least three radially adjacent segments; a central core segment having a positive ?1, a moat segment having a negative refractive index ?2, and a ring segment having a positive refractive index ?3, wherein ?1>?3>?c>?2. The DCF exhibits a negative dispersion slope of between ?0.29 and ?0.43 ps/nm2/km at 1575 nm, and a total dispersion less than ?96 and greater than ?108 ps/nm/km at 1575 nm. A transmission link including the combination of a SMF and the present invention DCF is also disclosed.

Abstract: Disclosed is a total dispersion and total dispersion slope compensating optical waveguide fiber. The refractive index profile of the compensating waveguide fiber includes a core region having a central segment and two surrounding annular segments. In an embodiment of the compensating waveguide fiber, a first clad layer adjacent the core region has a refractive index lower than that of a second clad layer adjacent the first clad layer. The optical waveguide fiber in accord with the invention has negative total dispersion and negative total dispersion slope over the operating window of the fiber to be compensated. The invention includes a compensated optical waveguide fiber span which includes a high performance waveguide fiber and a compensating waveguide fiber in accord with the invention.

Abstract: A burner and a method for producing an inorganic soot such as silica comprising a plurality of substantially planar layers having multiple openings therethrough formed by a micromachining process. The openings are in fluid communication with a precursor inlet and a gas inlet to permit the gas and the precursor to flow through and exit the burner. The burner produces a flame from a combustible gas in which the precursor undergoes a chemical reaction to form the soot.

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 higher order mode stripping optical fiber having a core surrounded and a cladding layer surrounded by a coupling coating having a higher refractive index than the higher order mode effective index and wherein the cladding-coating interface between the cladding and the coupling coating is located at a radius <55 microns. The measured cutoff wavelength of the fiber is preferably >1500 nm. Such fibers are particularly effective at attenuating unwanted higher order modes and are useful in Dispersion Compensating modules (DCM's). Modules and systems utilizing the higher order mode stripping fiber are also described.

Abstract: The present invention relates to a dispersion compensating optical fiber (“DC fiber”) having a segmented core of at least three segments and having a negative total dispersion and negative dispersion slope in the L-band. The index profile of the segmented core is selected to provide an optical fiber having properties suitable for a high performance communication system operating in the L-band wavelength band, i.e., between about 1570 nm to 1620 nm. The DC fiber according to the invention exhibits total dispersion at 1595 nm of between −70 and −225 ps/km/nm and dispersion slope more negative than −0.7 ps/km/nm2. The DC fiber may be optically connected to a non-zero dispersion shifted fiber in the system to compensate for dispersion and dispersion slope thereof.

Abstract: A method for the pregobbing of an optical fiber preform to provide pre-optimized tip taper and system for drawing optical fiber therefrom. The downtime of an optical fiber drawing apparatus can be considerably shortened, by providing preforms that have a pre-optimized tip shape. Pre-optimized tips are provided which are melted off at the tip by an induction heater of a heating furnace. Preferably, the pregobbing furnace has substantially the same temperature profile as the draw furnace. Therefore, because the tip of the preform is optimized and unusable glass has been removed, throughput of the draw apparatus is advantageously increased. Moreover, the shape of the tip of the preform is optimized in that it has been exposed to the same temperature profile as it would have seen had the draw tip been formed in the draw furnace.

Abstract: A DCF adapted to compensate for dispersion and slope of a length of SMF in the C-band window that includes a core surrounded by a cladding layer of refractive index &Dgr;c. The core includes at least three radially adjacent segments, a central core segment having a positive &Dgr;1, a moat segment having a negative refractive index &Dgr;2, and a ring segment having a positive refractive index &Dgr;3, wherein &Dgr;1>&Dgr;3 >&Dgr;c>&Dgr;2. The DCF exhibits a negative Dispersion Slope (DS), where −0.29 (ps/nm2·km) at 1546 nm, a dispersion (D), where −100<D<−120 (ps.nm·km) at 1546 nm, and a &kgr; value (D/DS) at 1546 nm that is preferably between 250 and 387 nm. The DCF preferably has a cutoff wavelength (&lgr;c) less than 1500 nm, attenuation at 1550 nm of less than 0.6 dB/km, and a bend loss of less than 0.01 dB/m on a 40 mm mandrel at 1550 nm.

Abstract: A method of protecting a silica-containing article used in the manufacture of an optical fiber includes the step of applying to the silica-containing article a protective layer that facilitates removal of particulates that deposit on the protective layer and that ablates during or can be removed before subsequent processing of the silica-containing article. An intermediate product used in the manufacture of an optical fiber and protected against break-inducing particulates includes a silica-containing article, and a protective layer that facilitates removal of particulates that have deposited on the protective layer and that can be ablated during or removed before subsequent processing of the intermediate product.