Patents Assigned to Fitel USA Corp.
  • Patent number: 7946133
    Abstract: Methods for modifying preform core ovality during and subsequent to the formation of an optical fiber preform. After MCVD deposition forms the core rod, but prior to overcladding of the core rod, the code rod may be etched to change its ovality. In order to etch the core rod, the core rod may be mounted to lathe, rotated by at least two rotors, and subjected to a heat source. Additionally, one of the at least two rotors may be phase-shifted from another one of the at least two rotors after the core rod is mounted on the lathe.
    Type: Grant
    Filed: November 12, 2010
    Date of Patent: May 24, 2011
    Assignee: Fitel USA Corp.
    Inventors: James William Fleming, Siu-Ping Hong, Paul Francis Glodis, Thomas John Miller, Zhi Zhou, David Kalish, Shunhe Xiong
  • Publication number: 20110056245
    Abstract: Methods for modifying preform core ovality during and subsequent to the formation of an optical fiber preform. After MCVD deposition forms the core rod, but prior to overcladding of the core rod, the code rod may be etched to change its ovality. In order to etch the core rod, the core rod may be mounted to lathe, rotated by at least two rotors, and subjected to a heat source. Additionally, one of the at least two rotors may be phase-shifted from another one of the at least two rotors after the core rod is mounted on the lathe.
    Type: Application
    Filed: November 12, 2010
    Publication date: March 10, 2011
    Applicant: FITEL USA CORP.
    Inventors: James William Fleming, Siu-Ping Hong, Paul Francis Glodis, Thomas John Miller, Zhi Zhou, David Kalish, Shunhe Xiong
  • Patent number: 7546750
    Abstract: Embodiments of the invention include a method for making optical fiber having reduced aging or hydrogen aging loss over the life of the fiber and optical fiber systems including such optical fibers. Improved silicon-oxygen stoichiometry during one or more preform manufacturing steps reduces the amount of Si defects generated in the optical fiber preform. Also, deuterium exposure of optical fiber drawn from the preform reduces the likelihood of having atomic defects such as Si defects in the optical fiber that, over time, attract and bond with hydrogen atoms to form molecules that contribute to increased water absorption loss. The inventive method produces optical fibers with improved transmission characteristics, e.g., optical fibers made by methods according to embodiments of the invention have transmission loss at 1385 nanometers that is less than 0.33 dB/km and the aging loss increase thereafter is less than 0.04 dB/km.
    Type: Grant
    Filed: July 15, 2003
    Date of Patent: June 16, 2009
    Assignee: Fitel USA Corp.
    Inventors: Kai H. Chang, David Kalish, Thomas John Miller
  • Patent number: 7440664
    Abstract: A microstructured optical waveguide is formed to include a periodic sequence of “plugs” of optically active material within the inner cladding air tunnels. The plugs are utilized as a grating structure for generating resonant and periodic structures. The waveguide (in one embodiment, an optical fiber) is tunable by changing the spacing of the plugs (e.g., heating the structure, changing the pressure within the structure, etc.), or by modifying the initial spacing of the plugs during the formation of the microstructured optical waveguide (i.e., by modifying the “dipping frequency” of the waveguide into a reservoir of optically active material). In general, any number of different types of optically active material may be used to form the plugs, where two or more different materials may be used in the same structure, and introduced in an alternating fashion.
    Type: Grant
    Filed: April 8, 2003
    Date of Patent: October 21, 2008
    Assignee: Fitel USA Corp.
    Inventors: Benjamin J. Eggleton, Justin D. Ging, Arturo Hale, Charles Kerbage
  • Patent number: 7352939
    Abstract: A microbend-induced fiber grating is formed from a section of optical fiber configured to exhibit “splitting” between the resonant wavelengths supported by the TE and TM components of the LP1m mode and the resonant wavelength supported by the odd/even HE2m components of the LP1m mode. Since only the TE and TM components are polarization dependent, by splitting and shifting the resonant wavelengths for these modes away from a system-desired wavelength(s) supported by the odd/even HE modes, a polarization insensitive microbend-induced fiber grating can be formed. A fiber core configuration including a central core region, trench and ring is formed to exhibit a large radial gradient in core refractive index profile, with a significantly steep transition between the ring index and the trench index, to provide the desired splitting between the (undesired, polarization sensitive) TE/TM modes and the HE mode.
    Type: Grant
    Filed: December 27, 2006
    Date of Patent: April 1, 2008
    Assignee: Fitel USA Corp.
    Inventor: Siddharth Ramachandran
  • Patent number: 7340139
    Abstract: A microbend-induced fiber grating is formed from a section of optical fiber configured to exhibit “splitting” between the resonant wavelengths supported by the TE and TM components of the LP1m mode and the resonant wavelength supported by the odd/even HE2m components of the LP1m mode. Since only the TE and TM components are polarization dependent, by splitting and shifting the resonant wavelengths for these modes away from a system-desired wavelength(s) supported by the odd/even HE modes, a polarization insensitive microbend-induced fiber grating can be formed. A fiber core configuration including a central core region, trench and ring is formed to exhibit a large radial gradient in core refractive index profile, with a significantly steep transition between the ring index and the trench index, to provide the desired splitting between the (undesired, polarization sensitive) TE/TM modes and the HE mode.
    Type: Grant
    Filed: December 27, 2006
    Date of Patent: March 4, 2008
    Assignee: Fitel USA Corp.
    Inventor: Siddharth Ramachandran
  • Patent number: 7271916
    Abstract: A fiber characterization arrangement utilizes Fourier domain optical coherence tomography (FDOCT) to measure the cross-section of optical fibers, thus providing information sub-surface features, coating thickness/concentricity and stress-induced birefringence under tension. The FDOCT technique can also be used to study microstructured fibers. By making FDOCT measurements on a fiber placed in a cavity, the geometric and optical thickness of the fiber can be simultaneously measured, allowing for the determination of the refractive index of the fiber.
    Type: Grant
    Filed: February 23, 2004
    Date of Patent: September 18, 2007
    Assignee: Fitel USA Corp
    Inventors: Jayesh Jasapara, Andrew D. Yablon
  • Patent number: 7272287
    Abstract: An in-line, distributed optical fiber filter comprises a core region with a raised refractive index (with respect to the surrounding cladding material) so as to allow for total internal reflection (TIR) of the desired transmission wavelength(s). One or more raised index features are formed within the cladding region and are configured so as to result in mode mixing between the cladding mode and core mode at determined wavelength(s) to be removed by filtering. The parameters associated with determining the proper core specifications and cladding specifications can be separately determined to provide for enhanced performance in terms of both filtering unwanted signals and propagation of desired communication signals.
    Type: Grant
    Filed: May 11, 2005
    Date of Patent: September 18, 2007
    Assignee: Fitel USA Corp
    Inventors: Ryan Tyler Bise, John Michael Fini, Man Fei Yan
  • Publication number: 20070125127
    Abstract: Methods for modifying preform core ovality during and subsequent to the formation of an optical fiber preform. After MCVD deposition forms the core rod, but prior to overcladding of the core rod, the code rod may be etched to change its ovality. In order to etch the core rod, the core rod may be mounted to lathe, rotated by at least two rotors, and subjected to a heat source. Additionally, one of the at least two rotors may be phase-shifted from another one of the at least two rotors after the core rod is mounted on the lathe.
    Type: Application
    Filed: February 8, 2007
    Publication date: June 7, 2007
    Applicant: FITEL USA CORP.
    Inventors: James Fleming, Siu-Ping Hong, Paul Glodis, Thomas Miller, Zhi Zhou, David Kalish, Shunhe Xiong
  • Patent number: 7218803
    Abstract: An apparatus and method for performing surface microscopy of an optical device uses an optical fiber taper including a microsphere endpoint as a near field probe. A transmission fiber is disposed adjacent to the microsphere so as to evanescently couple an optical test signal into the microsphere. A series of extremely narrow whispering gallery mode (WGM) resonances are created within the microsphere, with an associated electromagnetic field radiating outward therefrom. The microsphere probe may then be moved over the surface of an optical device being analyzed (or the device translated underneath the microsphere), where any abnormalities in the surface (such as defects, scratches and the like) will perturb the electromagnetic field pattern and be reflected in changes in the measured output power from the microsphere.
    Type: Grant
    Filed: March 24, 2006
    Date of Patent: May 15, 2007
    Assignee: Fitel USA Corp.
    Inventor: Mikhail Sumetsky
  • Patent number: 7177510
    Abstract: A microbend-induced fiber grating is formed from a section of optical fiber configured to exhibit “splitting” between the resonant wavelengths supported by the TE and TM components of the LP1m mode and the resonant wavelength supported by the odd/even HE2m components of the LP1m mode. Since only the TE and TM components are polarization dependent, by splitting and shifting the resonant wavelengths for these modes away from a system-desired wavelength(s) supported by the odd/even HE modes, a polarization insensitive microbend-induced fiber grating can be formed. A fiber core configuration including a central core region, trench and ring is formed to exhibit a large radial gradient in core refractive index profile, with a significantly steep transition between the ring index and the trench index, to provide the desired splitting between the (undesired, polarization sensitive) TE/TM modes and the HE mode.
    Type: Grant
    Filed: August 9, 2004
    Date of Patent: February 13, 2007
    Assignee: Fitel USA Corp.
    Inventor: Siddharth Ramachandran
  • Patent number: 7171089
    Abstract: Enhancement of the supercontinuum generation performance of a highly-nonlinear optical fiber (HNLF) is accomplished by performing at least one post-processing treatment on the HNLF. Particularly, UV exposure of the HNLF will modify its dispersion and effective area characteristics so as to increase its supercontinuum bandwidth, without resorting to techniques such as tapering or introducing unwanted reflections into the HNLF. The UV exposure can be uniform, slowly varying or aperiodic along the length of the HNLF, where the radiation will modify the nonlinear properties of the HNLF. Various other methods of altering these properties may be used. The output from the HNLF can be monitored and used to control the post-processing operation in order to achieve a set of desired features in the enhanced supercontinuum spectrum.
    Type: Grant
    Filed: February 22, 2005
    Date of Patent: January 30, 2007
    Assignee: Fitel USA Corp.
    Inventors: Kenneth S. Feder, Jeffrey W. Nicholson, Paul S. Westbrook
  • Patent number: 7149429
    Abstract: In a ring network comprising a plurality of nodes and a 16 channel coarse wavelength-division multiplexing (CWDM) plan, a technique is disclosed for adding and dropping channels that reduces the maximum attenuation loss that any channel encounters—thereby enabling longer rings to be constructed without using optical amplifiers in the ring. The 16 channels are typically distributed between the wavelengths 1310–1610 nm with 20 nm separation between channels. It is obscured that glass fibers have gradually decreasing loss at longer wavelengths in this band. The network includes a hub and several nodes that are interconnected by optical fibers in a ring configuration, where distance from the hub is the minimum value measure in either the clockwise or counterclockwise direction. Channels are assigned to the various nodes based on their wavelength. The channels whose wavelengths are near 1310 nm are assigned to nodes that are progressively closer to the hub.
    Type: Grant
    Filed: August 6, 2002
    Date of Patent: December 12, 2006
    Assignee: Fitel USA Corp.
    Inventor: Charles Ufongene
  • Patent number: 7143611
    Abstract: Embodiments of the invention include an optical fiber preform assembly and a method for making optical fiber using the preform assembly. The assembly includes a preform core rod, at least one overclad tube formed around the preform core rod, a handle attached to one end of the overclad tube, and a refractory material positioned in the overclad tube between the preform core rod and the handle. The refractory material reduces if not prevents movement of the preform core rod into the handle during the fiber draw process. Preferably, the refractory material is made of, e.g., magnesium oxide and/or aluminum oxide, and has a melting point, e.g., greater than approximately 2000 degrees Celsius. Embodiments of the invention also include a method for making optical fiber using this preform assembly.
    Type: Grant
    Filed: September 19, 2003
    Date of Patent: December 5, 2006
    Assignee: Fitel USA Corp
    Inventors: Joseph P. Fletcher, III, Andrew W. Jones, Thomas J. Miller, Don H. Smith, Shunhe Xiong
  • Patent number: 7139478
    Abstract: Embodiments of the invention include system for monitoring the effectiveness of pulse shaping in a nonlinear optical fiber (40). The spectral content of the pulse, after passing through the nonlinear fiber (40), provides an indication of how effectively the pulse was regenerated. A portion of the pulse exiting the nonlinear fiber is tapped off and its pulse energy is measured in at least one selected spectral region. The selected spectral region is one in which the pulse tends to gain energy when effective regeneration is taking place. The information concerning the effectiveness of pulse shaping in a nonlinear optical fiber is fed back to dynamically change the residual dispersion at the regenerator input. The spectral measurement leads to a control signal (48) to indicate a level of performance of the system, or to improve the performance of the system by adjusting an operational parameter.
    Type: Grant
    Filed: March 13, 2002
    Date of Patent: November 21, 2006
    Assignee: Fitel USA Corp.
    Inventors: Benjamin J. Eggleton, Tsing Hua Her, Stefan Hunsche, Gregory Raybon, John A. Rogers, Paul S. Westbrook
  • Patent number: 7116874
    Abstract: Enhancement of the supercontinuum generation performance of a highly-nonlinear optical fiber (HNLF) is accomplished by incorporating at least one Bragg grating structure in the HNLF. The Bragg grating results in reflecting a core-guided signal into signal which also remains core-guided. The supercontinuum radiation generated by such an arrangement will exhibit a substantial peak in its energy at the grating resonance of the Bragg grating and a region of increased radiation in a narrow wavelength band on the long wavelength side of the peak. A number of such Bragg gratings may be formed so as to “tailor” the enhancements provided in the supercontinuum radiation. Various, well-known Bragg grating modifications (tuning, chirped, blazed, etc.) may also be used in the inventive structure to enhance the generated supercontinuum.
    Type: Grant
    Filed: February 22, 2005
    Date of Patent: October 3, 2006
    Assignees: Fitel USA Corp., University of Rochester, Office of Technology Transfer
    Inventors: Thomas Brown, Kenneth S. Feder, Yufeng Li, Jeffrey W. Nicholson, Paul S. Westbrook
  • Patent number: 7116472
    Abstract: A rare-earth-doped optical fiber comprises a silica core region doped with a rare earth element and a cladding region adjacent the core region, characterized in that the core region is also doped with aluminum (Al) and fluorine (F). The presence of small amounts of F are effective to lower the refractive index, and hence the NA, of the core region even in the presence of significant amounts of Al (e.g., >8 mol %). Thus, the fiber has both a relatively flat gain spectrum and a low NA (e.g., <0.20). Also described are optical amplifiers that incorporate such fibers. Preferably the rare earth composition of the core includes at least erbium, and the core is also doped with germanium.
    Type: Grant
    Filed: February 18, 2005
    Date of Patent: October 3, 2006
    Assignee: Fitel USA Corp.
    Inventors: Matthew Julius Andrejco, Baishi Wang
  • Patent number: 7110646
    Abstract: A tunable optical fiber device comprises a length of fiber having a core having a certain refractive index; a cladding peripherally surrounding the core with a refractive index less than the refractive index of the core; and at least one hollow region disposed within the cladding in proximity to the core or within the core itself. Fluid (typically liquid) controllably moved within the hollow region modifies the effective index of the fiber and thereby tunes its characteristics.
    Type: Grant
    Filed: March 8, 2002
    Date of Patent: September 19, 2006
    Assignees: Lucent Technologies Inc., Fitel USA Corp.
    Inventors: Benjamin John Eggleton, Charles Kerbage, Peter Mach, John A. Rogers, Robert Scott Windeler
  • Patent number: 7110651
    Abstract: A new annular-core optical fiber is useful, inter alia, for stabilizing the behavior of an optical attenuator based on a Long Period Grating (LPG) against fluctuations in the polarization of the fundamental optical signal. The fiber dimensions and ?n are selected such that when a LPG of some period is used to couple fundamental-mode radiation in the fiber into higher-order modes, the wavelength of peak coupling into an HE mode is removed by at least 30 nm from the wavelength of peak coupling into the nearer of a TE mode or a TM mode.
    Type: Grant
    Filed: August 19, 2004
    Date of Patent: September 19, 2006
    Assignees: Lucent Technologies Inc., Fitel USA Corp.
    Inventors: Steven Eugene Golowich, Siddharth Ramachandran
  • Patent number: 7087841
    Abstract: A communication cable for being used in ducts or tubes comprising an outer jacket (1) which is formed with ribs (4) spaced around the periphery of the jacket and extending along the length of the cable. The new profiled cable has a lower index of friction when being installed in the ducts or tubes.
    Type: Grant
    Filed: March 12, 2002
    Date of Patent: August 8, 2006
    Assignee: Fitel USA Corp.
    Inventors: Dieter Fett, Olaf Grosskurth, Georg Josef Koebler, Jason Pedder, Elmar Staudinger