Patents by Inventor Stuart MacCormack
Stuart MacCormack 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: 7120174Abstract: A laser apparatus for generating optical pulses is disclosed, said laser apparatus has a reflecting gain element preferably including a fiber gain medium. The reflecting gain element is coupled to a controllable reflecting/transmitting module having a reflecting state and a transmitting state, wherein the controllable reflecting/transmitting means are operable to switch from the transmitting state to the reflecting state to initiate a build-up of an optical pulse, and to switch back to the transmitting state for outputting the optical pulse before it reaches the reflecting/transmitting means after a cavity roundtrip. In a preferred embodiment, the controllable reflecting/transmitting module includes an acousto-optic switch at an output end of a laser operable to output the optical pulse in zeroth diffraction order.Type: GrantFiled: June 14, 2004Date of Patent: October 10, 2006Assignee: JDS Uniphase CorporationInventors: Stuart MacCormack, Robert G. Waarts
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Patent number: 7016104Abstract: The present application relates to a Raman amplifier having an increased dynamic range, and particularly for laser pump sources and a method of pumping Raman fiber amplifiers over a greater dynamic range. In a multi-channel optical system, optical amplifiers must be able to provide gains over a large dynamic range, which is determined by the distribution of node-to-node distances in the network, as well as the number of channels. The present invention has found that the dynamic range of a Raman amplifier can be significantly increased by using pulse width modulation to pulse pump current at or near the minimum current stability threshold, in order to produce lower power output. The duty cycle of the pulsed current is selected to achieve a time-averaged operating condition, thus the time averaged pump power can be reduced in a linear fashion well below the capability of a continuous wave system.Type: GrantFiled: June 30, 2003Date of Patent: March 21, 2006Assignee: JDS Uniphase CorporationInventors: Erji Mao, Stuart MacCormack, Greg Roth, Steven Sanders
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Publication number: 20050276286Abstract: A laser apparatus for generating optical pulses is disclosed, said laser apparatus has a reflecting gain element preferably including a fiber gain medium. The reflecting gain element is coupled to a controllable reflecting/transmitting module having a reflecting state and a transmitting state, wherein the controllable reflecting/transmitting means are operable to switch from the transmitting state to the reflecting state to initiate a build-up of an optical pulse, and to switch back to the transmitting state for outputting the optical pulse before it reaches the reflecting/transmitting means after a cavity roundtrip. In a preferred embodiment, the controllable reflecting/transmitting module includes an acousto-optic switch at an output end of a laser operable to output the optical pulse in zeroth diffraction order.Type: ApplicationFiled: June 14, 2004Publication date: December 15, 2005Applicant: JDS Uniphase CorporationInventors: Stuart MacCormack, Robert Waarts
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Patent number: 6963681Abstract: The invention relates to a method for automatic dynamic gain control in optical Raman amplifiers and an optical Raman amplifier adapted for the same. The present invention has found that in multiple pump Raman amplifiers a substantially linear relationship exists between total amplified signal power and pump power for each of different wavelength pumps, in order to maintain an original gain profile and gain levels for an optical link with a fully loaded channel configuration, in response to dropped channels. In accordance with the method, and an amplifier programmed to practice the method, a set of pump power values and signal level values required to maintain the characterized gain profile and gain levels for a plurality of channel loading configurations are pre-established for the each pump wavelength. A linear function from each set of pre-established values is derived for each pump wavelength.Type: GrantFiled: June 30, 2003Date of Patent: November 8, 2005Assignee: JDS Uniphase CorporationInventors: Erji Mao, Stuart MacCormack, Greg Roth, Steven Sanders
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Publication number: 20050207455Abstract: A fiber amplifier is disclosed and includes a fiber amplifier body comprising a core of a first diameter, at least one signal conduit in optical communication with a signal source and the fiber amplifier body, the signal conduit sized to the first diameter, and one or more pump conduits configured to propagate pump radiation to the fiber amplifier body, the pump conduits in optical communication with at least one pump source.Type: ApplicationFiled: December 15, 2004Publication date: September 22, 2005Inventors: Stuart MacCormack, Dirk Kuizenga, Bernard Fidric, Hanna Hoffman
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Patent number: 6760151Abstract: A semiconductor pump laser uses a depolarzer to depolarize the pump light entering the fiber amplifier. The depolarized light source is useful for reducing polarization dependent gain of fiber amplifiers. The pump laser includes one or more semiconductor, coherence-collapsed laser sources emitting polarized pump outputs, and one or more depolarizers disposed to depolarize the polarized pump output from the lasers. One or more fiber outputs are coupled to the one or more depolarizers to receive depolarized pump light. The depolarizer may include an N×M polarization preserving coupler having N inputs and M outputs, N and M being at least 2, an input to the depolarizer at a first coupler input, an output port from the depolarizer at a first coupler output. A polarization-controlling optical path is coupled between a second coupler output and a second coupler input.Type: GrantFiled: April 27, 2000Date of Patent: July 6, 2004Assignee: JDS Uniphase CorporationInventors: Edward C. Vail, Mehrdad Ziari, Bernard Fidric, Jianping Zhang, Stuart MacCormack, Vincent E. Dominic
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Publication number: 20040052453Abstract: The invention relates to a method for automatic dynamic gain control in optical Raman amplifiers and an optical Raman amplifier adapted for the same. The present invention has found that in multiple pump Raman amplifiers a substantially linear relationship exists between total amplified signal power and pump power for each of different wavelength pumps, in order to maintain an original gain profile and gain levels for an optical link with a fully loaded channel configuration, in response to dropped channels. In accordance with the method, and an amplifier programmed to practice the method, a set of pump power values and signal level values required to maintain the characterized gain profile and gain levels for a plurality of channel loading configurations are pre-established for the each pump wavelength. A linear function from each set of pre-established values is derived for each pump wavelength.Type: ApplicationFiled: June 30, 2003Publication date: March 18, 2004Applicant: JDS Uniphase CorporationInventors: Erji Mao, Stuart MacCormack, Greg Roth, Steven Sanders
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Publication number: 20040036956Abstract: The present application relates to a Raman amplifier having an increased dynamic range, and particularly for laser pump sources and a method of pumping Raman fiber amplifiers over a greater dynamic range. In a multi-channel optical system, optical amplifiers must be able to provide gains over a large dynamic range, which is determined by the distribution of node-to-node distances in the network, as well as the number of channels. The present invention has found that the dynamic range of a Raman amplifier can be significantly increased by using pulse width modulation to pulse pump current at or near the minimum current stability threshold, in order to produce lower power output. The duty cycle of the pulsed current is selected to achieve a time-averaged operating condition, thus the time averaged pump power can be reduced in a linear fashion well below the capability of a continuous wave system.Type: ApplicationFiled: June 30, 2003Publication date: February 26, 2004Applicant: JDS Uniphase CorporationInventors: Erji Mao, Stuart MacCormack, Greg Roth, Steven Sanders
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Patent number: 6603896Abstract: The gain of a fiber amplifier is typically not uniform across the bandwidth used for amplifying optical communications signals. In a power fiber amplifier unit, having a fiber pre-amplifier and a fiber power amplifier, the gain tilt of the fiber power amplifier is generally set by the level of gain saturation. The gain tilt of the fiber pre-amplifier is adjustable by controlling the population inversion density in the amplifying medium. The gain tilt of the fiber pre-amplifier may be adjusted so as to at least partially compensate for the gain tilt of the power amplifier.Type: GrantFiled: September 29, 2000Date of Patent: August 5, 2003Assignee: JDS Uniphase CorporationInventors: Stuart MacCormack, David M. Giltner, David G. Mehuys
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Publication number: 20030142395Abstract: An optical fiber amplifier has a pump module operating at a shorter wavelength at room temperature than conventional optical fiber amplifiers. At the maximum operating case temperature, the output from the pump module is still at a lower wavelength than the upper absorption band edge of the optical fiber. In a further embodiment, an Er—Yb co-doped optical fiber is further doped with aluminum to flatten a portion of the optical absorption profile. Co-doping with aluminum reduces the sensitivity of optical amplifier output to wavelength drift of the pump module when pumped near the secondary peak.Type: ApplicationFiled: January 22, 2003Publication date: July 31, 2003Applicant: JDS Uniphase CorporationInventors: Stuart MacCormack, David Giltner, Ying Hua Zhang
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Publication number: 20030076577Abstract: A lossless optical link in an optical transmission system comprises an optical fiber that is configured to produce Raman gain and provide for Raman distributed gain, via one or more pump sources, along the fiber so that, as an end result, the gain experienced by one or more propagating signals in the fiber link is made fairly uniform along the link or at least a portion of the optical link, such as not vary, for example, no more than five dB along the length of the optical fiber. The several embodiments disclosed provide for different optical pump/component architectures to achieve this end result.Type: ApplicationFiled: December 22, 2000Publication date: April 24, 2003Inventors: Vincent G. Dominic, David F. Welch, Robert G. Waarts, Stuart MacCormack, Mehrdad Ziari, Robert J. Lang, Donald R. Scifres
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Publication number: 20030021009Abstract: An erbium doped fiber amplifier that includes two separate variable optical attenuators that provide signal attenuation to eliminate spectrum tilt of the amplified optical signal. The erbium doped fiber amplifier includes a first pre-amplifier stage, a second pre-amplifier stage and a power amplifier stage. A primary variable optical attenuator is positioned between the first pre-amplifier stage and the second pre-amplifier stage, and a secondary variable optical attenuator is positioned between the second pre-amplifier stage and the power amplifier stage. By providing two separate variable optical attenuators at two different locations, the internal loss variation in the erbium doped fiber amplifier is averaged to provide an improved amplifier design and noise figure performance.Type: ApplicationFiled: July 25, 2001Publication date: January 30, 2003Inventors: Stuart MacCormack, Steven Sanders
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Patent number: 6434295Abstract: All-fiber coupling architectures include at least one fiber gain media, e.g. a fiber amplifier or a fiber laser, providing for the coupling light from one or more multi-wavelength pump sources propagating in a multimode core fiber at multiple points along a double clad fiber or at least at one point along multiple double clad fibers having their inner claddings fused to the multimode core fiber. The latter arrangement provides for a low cost utility multi-signal fiber amplifier for telecommunication applications.Type: GrantFiled: January 13, 2000Date of Patent: August 13, 2002Assignee: JDS Uniphase CorporationInventors: Stuart MacCormack, Vincent G. Dominic, Robert G. Waarts
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Publication number: 20020106156Abstract: An optical gain apparatus has a pump source providing pump energy at a pump wavelength to a gain medium that generates optical energy at a signal wavelength. To minimize disturbance from signal wavelengths appearing in a coupling path between the pump source and the gain medium, an optical attenuator is located in the coupling path that provides a significant degree of attenuation to signal wavelengths, while providing negligible attenuation of pump wavelengths. The attenuator may comprise a grating structure, such as a long period grating or a blazed grating. It may also comprise an angled coupling fiber that is oriented to reflect signal wavelengths out of the coupling path. The end of such a fiber would typically be formed into a microlens, such as a wedge-shaped lens or a biconic lens, and would preferably be coated with a material that is highly reflective at the signal wavelength, but anti-reflective at the pump wavelength. The microlens may also be angled relative to a longitudinal axis of the fiber.Type: ApplicationFiled: February 2, 2001Publication date: August 8, 2002Inventors: Edward Vail, Radhakrishnan Nagarajan, Harrison Ransom, Ian Booth, Tae Jim Kim, Edmund Wolak, Jo Major, Stuart MacCormack, Tanya Oleskevich
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Patent number: 6407855Abstract: Optical pumping arrangements are provided for the broadband or multiple wavelength pumping of optical sources. Sources may be based on Raman gain media and may use multiple output couplers to couple out different wavelength ranges. Cascaded Raman resonator (CRR) configurations may also be used. Overlapping resonators at different wavelengths may be configured to share gain media, and may have separate portions in separate optical paths. Attenuation filters may also be used that are matched to the gain profile of a gain medium, to flatten the gain spectrum and allow equalization of gain to different output wavelengths. In one embodiment, polarization maintaining fiber is used to develop resonant conditions at different wavelengths in different polarization states. Wideband output gratings may be substituted for narrowband gratings to provide CRR configurations with a broader output band. Broadband amplification may also be provided by using a laser source operating in coherence collapse.Type: GrantFiled: October 29, 1999Date of Patent: June 18, 2002Assignee: SDL, Inc.Inventors: Stuart MacCormack, David M. Giltner, Vincent G. Dominic, Donald R. Scifres, Bardia Pezeshki, Edward C. Vail, Mehrdad Ziari, Robert G. Waarts
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Patent number: 6282016Abstract: A number of variations are provided of a device that provides an amplified single polarization optical signal. Each of these relies on the use of a non-polarization maintaining gain medium through which the signal is directed, and a polarization shifter and reflector that direct the signal back through the same gain medium with a shifted polarization state. An input polarization beamsplitter directs the returning optical signal away to an output, based on its shifted polarization state. The embodiments of the invention include the use of double-clad fiber. Multiple stages may be used to provide specific amplification parameters. In particular, a fiber with a relatively large mode field diameter may be used to enable high pulse power applications. Wavelength selective components are used in certain embodiments of the invention, to allow for wavelength selectivity, as well as a single polarization state, in amplifiers, lasers and amplified spontaneous emission (ASE).Type: GrantFiled: December 1, 1999Date of Patent: August 28, 2001Assignee: SDL, Inc.Inventors: Stuart MacCormack, Robert G. Waarts, Paul Freeman, Stephen G. Grubb
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Patent number: 6275250Abstract: Double clad fiber gain medium systems particularly adapted for marking indicia on surfaces of articles are disclosed. These systems provide a modulated output from a pump or seed semiconductor laser source to a double clad fiber gain medium which provides an amplified marking output scanned over the article surface with an optical scanner forming a plurality of strokes, the completion of which results in the indicia.Type: GrantFiled: January 21, 1999Date of Patent: August 14, 2001Assignee: SDL, Inc.Inventors: Steven Sanders, David F. Welch, Stuart MacCormack, Ramon E. Alvarez
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Patent number: 6049415Abstract: A number of variations are provided of a device that provides an amplified single polarization optical signal. Each of these relies on the use of a non-polarization maintaining gain medium through which the signal is directed, and a polarization shifter and reflector that direct the signal back through the same gain medium with a shifted polarization state. An input polarization beamsplitter directs the returning optical signal away to an output, based on its shifted polarization state. The embodiments of the invention include the use of double-clad fiber. Multiple stages may be used to provide specific amplification parameters. In one embodiment, both amplification stages reside in the same polarization shifting optical path. A polarization maintaining amplifier of this type may be used as part of a master oscillator-power amplifier, in which polarization maintaining fiber is used as part of the source laser.Type: GrantFiled: December 8, 1997Date of Patent: April 11, 2000Assignee: SDL, Inc.Inventors: Stephen G. Grubb, Paul Freeman, Stuart MacCormack, Robert G. Waarts
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Patent number: 5729375Abstract: An optical amplification system directs a diffraction-limited signal beam through a series of crossings, at substantially less than 90.degree. crossing angles, with a number of non-diffraction-limited pump beams in a photorefractive medium. The pump beams are e-polarized while the signal beam travels down the crystal medium's c-axis and is polarized in the same plane as the pump beam polarization, resulting in an energy transfer from the pumps to the signal beam while leaving the signal beam diffraction-limited. The photorefractive medium is preferably a series of BaTiO.sub.3 :Rh crystals that are aligned parallel to the angled edge of a wedged-shape prism through which the pump beams are transmitted, with the crystals cut so that their C-axes are parallel to the signal beam.Type: GrantFiled: March 1, 1996Date of Patent: March 17, 1998Assignees: Hughes Electronics, University of Southern CaliforniaInventors: Marvin B. Klein, Barry Wechsler, Jack L. Feinberg, Stuart MacCormack
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Patent number: 5717516Abstract: An optical amplification system directs a diffraction-limited signal beam through a series of approximately 90.degree. crossings with a number of non-diffraction-limited pump beams in a photorefractive medium. All of the beams are s-polarized, resulting in an energy transfer from the pumps to the signal beam while leaving the signal beam diffraction-limited. The photorefractive medium is preferably a series of BaTiO.sub.3 :Rh crystals that receive the pump and signal beams through orthogonal faces, with their C-axes at approximately 45.degree. to both beams. A binary tree optical distribution network is used to minimize waveguide splits in forming a large number of pump beams.Type: GrantFiled: April 4, 1997Date of Patent: February 10, 1998Assignees: Hughes Electronics, SDL, Inc.Inventors: Marvin B. Klein, David M. Pepper, Ronald R. Stephens, Thomas R. O'Meara, David Welch, Robert J. Lang, Jack L. Feinberg, Stuart MacCormack