Abstract: There is provided a method for making hollow microspheres including heating a feed under conditions sufficient to convert at least a portion of the feed into hollow microspheres, where the heating is conducted under a vacuum. There is also provided hollow microspheres made using this method.

Abstract: Methods of making ceramic fibers and beads are disclosed.

Abstract: A method and apparatus is provided for estimating a speed-adapted channel. The method is operative to use a known transmit symbol of guide frequency field in each slot to derive a corresponding fading value of the guide frequency field in the estimation to decide feedback channel by linear interpolation at first; and accumulate and average them for eliminating noise and performing interpolation process for the channel fading value in an outgoing data field; then according to the moving speed of a mobile station, adjust the length of the channel fading of the guide frequency which takes part in the accumulation to adapt to influence caused by different channel fading. It realizes the objectives of making more subscribers to get better and necessary services and making use of the system's resource effectively and reasonably.

Abstract: Disclosed is a single mode optical waveguide fiber having a low cut off wavelength, and mode field diameter and bend resistance similar to step index single mode optical waveguide fiber designed for use at 1310 nm. By including a clad region of raised refractive index spaced apart from the core region of the single mode optical waveguide fiber, the cut off wavelength can be reduced to 850 nm. The single mode optical waveguide fiber in accord with the invention may also have a core region having a reduced refractive index on centerline surrounded by a region of higher refractive index and a clad region which is substantially uniform. The single mode optical waveguide fiber is thus ideally suited for use with the low cost, reliable VCSEL operating at 850 nm, a Fabry-Perot laser operating at 1310 nm, or a distributed feedback laser operating at 1550 nm thereby enabling low cost, easily installed, home access portions of the broadband telecommunications system.

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 method for manufacturing optical fiber with enhanced photosensitivity comprising the step of: forming a molten layer of glass and drawing a fiber from the molten layer of glass at a temperature of between about 1900° C. and 1995° C. Draw tension can be adjusted to attain the desired draw speed.

Abstract: An optical fiber for signal amplification comprises a core, doped with at least 15% phosphorus by weight and a rare earth ion sufficient to provide amplification of an optical signal. The fiber also comprises a clad layer surrounding the core with an inner portion and an outer portion. The refractive index of the inner portion of the clad layer is lower than that at the outer radius of the core region. This depressed inner clad portion serves to confine electromagnetic radiation within a selected wavelength range to substantially only the core.

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: The present invention provides an optical fiber suitable for the manufacture of optical fiber couplers and having low bend loss, low splice loss, and low attenuation. The optical fibers according to one aspect of the invention have bending loss of less than 0.5 dB at 1560 nm when wrapped 5 turns around a 20 mm mandrel; and an average fiber pull test loss of less than 0.1 dB in the wavelength range of 1530 nm to 1550 nm. The present invention also includes optical fiber components made from these optical fibers.

Abstract: A dispersion and dispersion slope compensating optical fiber includes a segmented core and a cladding layer wherein the refractive index profile is selected to provide a dispersion having a maximum deviation of less than 7 ps/nm-km over a wavelength band from 1550 nm to 1610 nm. According to a further embodiment of the invention, a dispersion compensating optical fiber is provided having a refractive index profile with a central core segment having a positive relative refractive index; a depressed moat segment on a periphery of the central core segment having a relative refractive index that is more negative than −1.2%; and an annular ring segment outward from the depressed moat segment having a relative refractive index that is greater than 1.2%.

Abstract: Disclosed is a dispersion compensating optical fiber that includes a refractive index profile selected to provide dispersion at 1550 nm of between −90 and −150 ps/nm/km; dispersion slope at 1550 nm of less than −1.5 ps/nm2/km; and kappa of between 40 and 95. The profile preferably has a core surrounded by a cladding layer of refractive index &Dgr;c, and at least three radially adjacent regions including a central core region having &Dgr;1, a moat region having a refractive index &Dgr;2, and an annular ring region having a refractive index &Dgr;3, wherein &Dgr;1>&Dgr;3>&Dgr;c>&Dgr;2.

Abstract: A optical fiber, for example a Dispersion Compensation (DC) fiber, for compensating dispersion of a transmission fiber (such as a NZDSF) and transmission line including same. The fiber has a refractive index profile having a first moat with a negative delta (&Dgr;2), and a second moat with a negative delta (&Dgr;4) wherein the fiber exhibits a negative total dispersion at 1550 nm, and kappa at 1550 nm of less than 75 nm. The DC fiber, when used in a transmission line, may provide low residual dispersion across the C band when such lines include transmission fibers with total dispersion between 2 and 6 ps/nm/km and dispersion slope less than 0.092 ps/nm2/km at 1550 nm.

Abstract: The present invention includes a method of making a preform for an enhanced photosensitive fiber comprising depositing successive layers of optical material the inside a tube using modified chemical vapor deposition, and collapsing the layers of optical material in a reducing atmosphere with a positive pressure. The present invention also includes a method of making an enhanced photosensitive fiber comprising making a preform using modified chemical vapor deposition wherein the preform is collapsed in a reducing atmosphere with a positive pressure and drawing the preform into a fiber.

Abstract: The present invention provides an optical fiber suitable for the manufacture of optical fiber couplers and having low bend loss, low splice loss, and low attenuation. The optical fibers according to one aspect of the invention have bending loss of less than 0.5 dB at 1560 nm when wrapped 5 turns around a 20 mm mandrel; and an average fiber pull test loss of less than 0.1 dB in the wavelength range of 1530 nm to 1550 nm. The present invention also includes optical fiber components made from these optical fibers.

Abstract: A dispersion compensating module, mode converter, coupler and dispersion compensated optical fiber therein. The dispersion compensating fiber has a plurality of core segments, the refractive index profile being selected to exhibit properties such that an LP02 mode at 1550 nm may be propagated a distance (generally 0.5-3.0 km), upon conversion to LP02, to compensate for dispersion of a length of transmission waveguide preferably greater than 25 km propagating in an LP01 mode. In another embodiment, the dispersion compensating module has a mode converter having a reflective fiber grating for converting a first to a second mode interconnected to a dispersion compensated fiber propagating in the second mode. The mode converter has a coupler adapted to operatively couple light propagating in a first mode from a first fiber into a second, and a reflective fiber grating operatively coupled to the second fiber; the grating being capable of converting light from the first into the second mode.

Abstract: A method and apparatus is provided for estimating a speed-adapted channel. The method is operative to use a known transmit symbol of guide frequency field in each slot to derive a corresponding fading value of the guide frequency field in the estimation to decide feedback channel by linear interpolation at first; and accumulate and average them for eliminating noise and performing interpolation process for the channel fading value in an outgoing data field; then according to the moving speed of a mobile station, adjust the length of the channel fading of the guide frequency which takes part in the accumulation to adapt to influence caused by different channel fading. It realizes the objectives of making more subscribers to get better and necessary services and making use of the system's resource effectively and reasonably.

Abstract: An optically active phosporus-silicate glass when pumped to directly excite Er ions, provides gain in 1565 nm to 1620 nm range and comprises in weight percent: SiO2 50 to 92%; Er2O3 0.01 to 2%; P2O5 greater than 5%; and Al2O3 0.0 to 0.3%.

Abstract: Disclosed is a dispersion compensating optical fiber that includes a refractive index profile selected to provide dispersion at 1550 nm of between −90 and −150 ps/nm/km; dispersion slope at 1550 nm of less than −1.5 ps/nm2/km; and kappa of between 40 and 95. The profile preferably has a core surrounded by a cladding layer of refractive index &Dgr;c, and at least three radially adjacent regions including a central core region having &Dgr;1, a moat region having a refractive index &Dgr;2, and an annular ring region having a refractive index &Dgr;3, wherein &Dgr;1>&Dgr;3>&Dgr;c>&Dgr;2.

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.