Patents by Inventor James W. Sulhoff
James W. Sulhoff has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8265490Abstract: Disclosed herein are embodiments of a device, method of use and system for an analog multi-wavelength transamplifier. The transamplifier embodiments described herein allow the use of multiple wavelengths to segment logical service groups, such as for use in a CATV distribution system and a FTTH system having a broadband overlay. Improved optical signal power performance can be achieved by using direct modulating transmitters and maintaining polarization of the optical signals that are modulated by a phase modulator, such as an external waveguide.Type: GrantFiled: May 28, 2009Date of Patent: September 11, 2012Assignee: Cisco Technology, Inc.Inventors: Fernando X. Villarruel, Steven C. Condra, Yihong Chen, Kevin L. Sweeney, James W. Sulhoff
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Patent number: 8111992Abstract: Provided herein are embodiments of a device, method of use and system for a low-cost analog multi-wavelength video distribution transamplifier for CATV and FTTH networks having a broadband overlay. The transamplifier embodiments described herein allow the use of multiple wavelengths to segment logical service groups in a CATV distribution system and a FTTH system having a broadband overlay.Type: GrantFiled: June 19, 2007Date of Patent: February 7, 2012Inventors: Fernando X. Villarruel, Steven C. Condra, Yihong Chen, Kevin L. Sweeney, James W. Sulhoff
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Patent number: 7903980Abstract: Provided herein are embodiments of a device, method of use and system for a low-cost analog multi-wavelength video distribution transamplifier for CATV and FTTH networks having a broadband overlay. The transamplifier embodiments described herein allow the use of multiple wavelengths to segment logical service groups in a CATV distribution system and a FTTH system having a broadband overlay. Improved optical signal power performance can be achieved by using direct modulating transmitters and modulating the optical signal for with an external waveguide, thereby decreasing SBS and reducing non-linearities.Type: GrantFiled: June 19, 2007Date of Patent: March 8, 2011Inventors: Fernando X. Villarruel, Steven C. Condra, Yihong Chen, Kevin L. Sweeney, James W. Sulhoff
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Publication number: 20090232500Abstract: Disclosed herein are embodiments of a device, method of use and system for an analog multi-wavelength transamplifier. The transamplifier embodiments described herein allow the use of multiple wavelengths to segment logical service groups, such as for use in a CATV distribution system and a FTTH system having a broadband overlay. Improved optical signal power performance can be achieved by using direct modulating transmitters and maintaining polarization of the optical signals that are modulated by a phase modulator, such as an external waveguide.Type: ApplicationFiled: May 28, 2009Publication date: September 17, 2009Inventors: FERNANDO X VILLARRUEL, STEVEN C. CONDRA, YIHONG CHEN, KEVIN L. SWEENEY, JAMES W. SULHOFF
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Publication number: 20080317468Abstract: Provided herein are embodiments of a device, method of use and system for a low-cost analog multi-wavelength video distribution transamplifier for CATV and FTTH networks having a broadband overlay. The transamplifier embodiments described herein allow the use of multiple wavelengths to segment logical service groups in a CATV distribution system and a FTTH system having a broadband overlay. Improved optical signal power performance can be achieved by using direct modulating transmitters and modulating the optical signal for with an external waveguide, thereby decreasing SBS and reducing non-linearities.Type: ApplicationFiled: June 19, 2007Publication date: December 25, 2008Inventors: Fernando X. Villarruel, Steven C. Condra, Yihong Chen, Kevin L. Sweeney, James W. Sulhoff
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Publication number: 20080317467Abstract: Provided herein are embodiments of a device, method of use and system for a low-cost analog multi-wavelength video distribution transamplifier for CATV and FTTH networks having a broadband overlay. The transamplifier embodiments described herein allow the use of multiple wavelengths to segment logical service groups in a CATV distribution system and a FTTH system having a broadband overlay.Type: ApplicationFiled: June 19, 2007Publication date: December 25, 2008Inventors: Fernando X. Villarruel, Steven C. Condra, Yihong Chen, Kevin L. Sweeney, James W. Sulhoff
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Patent number: 6687049Abstract: Optical amplifiers and optical network equipment are provided that have optical gain stages for amplifying optical signals on a fiber-optic communications link. The optical gain stages may be based on optically pumped fiber such as rare-earth-doped fiber. The fiber may be optically pumped using laser diode pumps. A control unit may be provided in the amplifiers or other equipment to control the laser diode pumps. Optical monitors may be used to measure the optical signals in the amplifiers or other equipment. The pump powers of the laser diode pumps may be adjusted in real time by the control unit based on the measured optical signals to suppress gain transients due to input power fluctuations on the link. To minimize the impact of pump-induced noise, the control unit may avoid operating the laser diodes at powers at which the laser diodes are most susceptible to mode partition noise.Type: GrantFiled: August 15, 2001Date of Patent: February 3, 2004Assignee: Onetta, Inc.Inventors: James W. Sulhoff, Yongan Wu, Chia-Chi Wang
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Patent number: 6424457Abstract: Optical amplifiers and methods for manufacturing optical amplifiers are provided that allow amplifiers to be fabricated to match design expectations. Optical amplifiers may be manufactured by assembling passive optical components in the amplifier before assembling active optical components such as doped fiber coils. Passive losses may then be characterized and used to calculate the lengths of the fibers that should be used in the amplifier gain stages. Following corrections to the nominal doped-fiber lengths based on the measured passive losses, the passive and active components of the amplifier may be assembled and characterized. Final corrections may be made to the amplifier assembly based on these characterizations. For example, the lengths of one or more of the doped fibers may be adjusted. If desired, such length adjustments may be made to fiber coils in the mid-stage portion of the amplifier, so that the impact on the operating characteristics of the amplifier are minimized.Type: GrantFiled: December 5, 2000Date of Patent: July 23, 2002Assignee: Onetta, Inc.Inventors: James P. Koonmen, James W. Sulhoff, Chia-Chi Wang, Paul F. Wysocki
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Patent number: 6094298Abstract: An Erbium doped fiber amplifier (EDFA) is placed in a laser cavity to clamp the gain of the amplifier. The laser cavity is preferably formed to minimize the effects of relaxation oscillations and of spectral hole burning. In a preferred embodiment, the laser cavity supports a lasing wavelength which makes the saturation energy at the laser wavelength less than that at the signal wavelengths. In an erbium doped fiber implementation, the laser wavelength is shorter than that of the signal wavelengths and is separated from them by no more than approximately 75% of the width of the spectral hole. The compounding of relaxation oscillations may be substantially eliminated by varying the length of the fiber within each laser cavity within a system to change the photon round-trip time within each cavity.Type: GrantFiled: July 6, 1999Date of Patent: July 25, 2000Assignee: Lucent Technologies Inc.Inventors: Gengxian Luo, Atul K. Srivastava, James W. Sulhoff, Yan Sun, John L. Zyskind
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Patent number: 6049416Abstract: A method for determining the optimal design of a gain equalization filter (GEF) used in optical fiber amplifiers. The method is suitable for erbium-doped fiber amplifiers (EDFA) that are widely used in wavelength-division-multiplexed (WDM) optical communication systems and networks.Type: GrantFiled: January 30, 1998Date of Patent: April 11, 2000Assignee: Lucent Technologies Inc.Inventors: Atul Kumar Srivastava, James W. Sulhoff, Yan Sun, John Lehrer Zyskind
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Patent number: 6025941Abstract: We have recognized that in a Wavelength Division Multiplex (WDM) ring network with a closed loop, the possibility of lasing at Amplified Spontaneous Emissions (ASE) wavelengths exists. In accordance with the present invention, we provide a technique for protecting against lasing in a WDM ring network comprising a plurality of serially connected node links, each node link including a segment of optical fiber and an access node site for adding or dropping one or more active wavelength channels to a transmission bandwidth of the network. The protection means changes the optical transmission characteristics of the transmission bandwidth of the network to ensure that the network loop gain at any wavelength is always less than the network loop loss.Type: GrantFiled: September 15, 1997Date of Patent: February 15, 2000Assignee: Lucent Technologies Inc.Inventors: Atul Kumar Srivastava, James W. Sulhoff, Yan Sun, John Lehrer Zyskind
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Patent number: 6008932Abstract: An Erbium doped fiber amplifier (EDFA) is placed in a laser cavity to clamp the gain of the amplifier. The laser cavity is preferably formed to minimize the effects of relaxation oscillations and of spectral hole burning. In a preferred embodiment, the laser cavity supports a lasing wavelength which makes the saturation energy at the laser wavelength less than that at the signal wavelengths. In an erbium doped fiber implementation, the laser wavelength is shorter than that of the signal wavelengths and is separated from them by no more than approximately 75% of the width of the spectral hole. The compounding of relaxation oscillations may be substantially eliminated by varying the length of the fiber within each laser cavity within a system to change the photon round-trip time within each cavity.Type: GrantFiled: October 7, 1997Date of Patent: December 28, 1999Assignee: Lucent Technologies Inc.Inventors: Gengxian Luo, Atul K. Srivastava, James W. Sulhoff, Yan Sun, John L. Zyskind
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Patent number: 5900969Abstract: An optical amplifier that receives an optical signal at an input of the optical amplifier is arranged so that it amplifies the signal and then adjusts the level of the amplified input signal to a predetermined level. The optical amplifier, which includes a filter to substantially decrease the wavelength dependence of the optical amplifier, then amplifies the adjusted signal and supplies the resulting signal to an output.Type: GrantFiled: February 14, 1997Date of Patent: May 4, 1999Assignee: Lucent Technologies Inc.Inventors: Atul Kumar Srivastava, James W. Sulhoff, Yan Sun, Jianhui Zhou, John Lehrer Zyskind
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Patent number: 5900968Abstract: In a WDM network employing a plurality of optical amplifiers in at least one optical fiber link, a system and method for dynamically controlling gain in accordance with the collective behavior of the amplifier chain. According to the present invention, the required response time of dynamic gain control is selected substantially inversely relative to the number of amplifiers in the communication path. Illustratively, in a large-scale optical network (with signal channel paths traversing say, a hundred optical amplifiers), the response time of gain control in accordance with the present invention may be on the order of 5 .mu.s or even less.Type: GrantFiled: October 10, 1996Date of Patent: May 4, 1999Assignee: Lucent Technologies Inc.Inventors: Atul Kumar Srivastava, James W. Sulhoff, Yan Sun, Robert William Tkach, John Lehrer Zyskind
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Patent number: 5430572Abstract: High output power, high gain, and low noise are achieved in a two-stage optical amplifier, suitable for use as a repeater for a long haul lightwave communication system, in accordance with the principles of the invention, by employing a first amplifying stage having a signal gain sufficiently small to prevent self-saturation by amplified stimulated emission (ASE) that uses counter-propagating pump light to cause maximum inversion of the first stage amplifying medium. In an illustrative embodiment of the invention, EDFAs are used in each of two amplifying stages. The length of the EDFA in the first stage is short enough to ensure nearly complete inversion of the EDFA from pump light that counter-propagates with the signal. The counter-propagating pump light allows the invention to advantageously avoid the significant noise figure penalty from the input loss associated with co-propagating pump light.Type: GrantFiled: September 30, 1993Date of Patent: July 4, 1995Assignee: AT&T Corp.Inventors: David J. DiGiovanni, Joseph D. Evankow, Jonathan A. Nagel, Richard G. Smart, James W. Sulhoff, John L. Zyskind
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Patent number: 5406404Abstract: The present invention relates to a method of mitigating gain peaking in a chain of fiber amplifiers by pumping the amplifiers at a predetermined wavelength to produce gain over a specified wavelength range.Type: GrantFiled: November 2, 1993Date of Patent: April 11, 1995Assignee: AT&T Corp.Inventors: David J. DiGiovanni, Jonathan A. Nagel, Richard G. Smart, James W. Sulhoff, John L. Zyskind
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Patent number: 5223705Abstract: In an embodiment for obtaining accurate noise figure measurements for any degree of saturation of an optical amplifier, a polarizer is located at the output of the optical amplifier. The amplified spontaneous noise (ASE) produced by an optical amplifier is not polarized, whereas the amplified signal has a well defined state of polarization which is preferably linear. If the amplified signal is not linearly polarized, it can be rendered linearly polarized in one direction by means of a polarization controller located downstream of the polarizer. By setting the polarizer to have its state of polarization orthogonal to that of the linearly polarized amplified signal, the spectral density of the ASE from the polarizer can be measured without associated distortion due to the signal. By sequentially adjusting the polarization controller to minimize and then maximize the signal which it passes, sequential measurements of the ASE spectral density and gain of the optical amplifier can be obtained.Type: GrantFiled: August 12, 1992Date of Patent: June 29, 1993Assignee: AT&T Bell LaboratoriesInventors: Jennifer Aspell, Neal S. Bergano, Bruce M. Nyman, Richard G. Smart, James W. Sulhoff, John L. Zyskind
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Patent number: 5181210Abstract: A compact all-fiber, electrically tunable ring laser includes a diode-pumped erbium-doped fiber amplifier. The frequency of the laser is tuned by a fiber Fabry-Perot (FFP) etalon that is electrically tuned. An in-line optical isolator is used in conjunction with the FFP to eliminate undesired reflections. A second FPP with a narrow free spectral range (FSR) can be used in conjunction with a first FFP with a wide FSR.Type: GrantFiled: January 13, 1992Date of Patent: January 19, 1993Assignee: AT&T Bell LaboratoriesInventors: Yun C. Chung, David J. DiGiovanni, Julian Stone, James W. Sulhoff, John L. Zyskind
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Patent number: 5132976Abstract: A compact all-fiber, electrically tunable ring laser includes a diodepumped erbium-doped fiber amplifier. The frequency of the laser is tuned by a fiber Fabry-Perot(FFP) etalon that is electrically tuned. An in-line optical isolator is used in conjunction with the FFP to eliminate undesired reflections. A second FFP with a narrow free spectral range (FSR) can be used in conjunction with a first FFP with a wide FSR.Type: GrantFiled: May 28, 1991Date of Patent: July 21, 1992Assignee: AT&T Bell LaboratoriesInventors: Yun C. Chung, David J. DiGiovanni, Julian Stone, James W. Sulhoff, John L. Zyskind
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Patent number: 4999694Abstract: In this invention, there is disclosed a new photodiode which comprises a semimetal/semiconductor junction. Distortion of the bands associated with this type of junction result in current flow when an electron hole pair is formed by, for example, a photon impinging upon the junction. The photodiode operates in the photovoltaic mode. However, rather than relying on impurity doping to fabricate a p-n junction, the semimetallic nature of HgTe and its large conduction band offsets with Hg.sub.1-x Cd.sub.x Te are used to create a rectifying Schottky like structure.Type: GrantFiled: August 18, 1989Date of Patent: March 12, 1991Assignee: AT&T Bell LaboratoriesInventors: Richard F. Austin, Robert D. Feldman, James W. Sulhoff, John L. Zyskind