Patents by Inventor Farhad Hakimi
Farhad Hakimi 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: 6404526Abstract: A method of generating a signal including: generating a first sequence of coherent optical pulses which are sufficiently close in spacing so as to overlap and interfere upon traveling a predetermined length down an optical fiber to form a first interference pattern with a first central lobe having a characteristic wavelength, wherein the energy of the pulses of the first sequence of pulses is within the non-linear regime of the optical fiber; manipulating the first sequence of optical pulses; in a similar manner generating a second sequence of coherent optical pulses; manipulating the second sequence of optical pulses; and introducing both the first and second manipulated sequences of pulses into the optical fiber, wherein the manipulating of the pulses of the first and the second sequence of pulses shifts the characteristic wavelengths of the first and second central lobes, respectively, to first and second transmission signal wavelengths.Type: GrantFiled: March 8, 2001Date of Patent: June 11, 2002Assignee: Massachusetts Institute of TechnologyInventors: Farhad Hakimi, Hosain Hakimi
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Publication number: 20020061164Abstract: A method introduces variable time offsets into a stream of optical pulses. The method includes receiving a plurality of coherent optical pulses, receiving a plurality of control signals, and forming a coherent pulse array (CPA) from each pulse in response to one of the received control signals. Temporal spacings between pulses of each CPA are responsive to the associated one of the received control signals. For optical control signals, response times can be very short. The method further includes transmitting each pulse through a dispersive optical medium. The act of transmitting makes pulses of each CPA overlap to form an interference pattern.Type: ApplicationFiled: November 8, 2001Publication date: May 23, 2002Applicant: Massachusetts Institute of Technology, a Massachusetts corporationInventors: Katherine L. Hall, Hosain Hakimi, Farhad Hakimi, Daniel T. Moriarty, Kristin A. Rauschenbach
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Patent number: 6384945Abstract: A method of generating a signal pulse in an optical fiber characterized by dispersion and a refraction index that has a nonlinear regime of operation, the method including generating a sequence of coherent optical pulses each of which has an associated energy; and introducing the sequence of pulses into the optical fiber, wherein the pulses in the sequence of pulses are sufficiently close in spacing so that after traveling a predetermined length down the optical fiber, the pulses of the sequence of pulses overlap and interfere to form an interference pattern, and wherein the associated energy of at least one of the pulses of the sequence of pulses is within the nonlinear regime of the optical fiber.Type: GrantFiled: November 22, 2000Date of Patent: May 7, 2002Assignee: Massachusetts Institute of TechnologyInventors: Farhad Hakimi, Hosain Hakimi
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Patent number: 6370297Abstract: An optical amplifier includes first and second optical fibers. The first optical fiber has a core, a first cladding surrounding the core and a second cladding surrounding the first cladding. The second optical fiber has an end physically coupled to a side portion of the first optical fiber. The end transmits light to the first cladding.Type: GrantFiled: March 31, 1999Date of Patent: April 9, 2002Assignee: Massachusetts Institute of TechnologyInventors: Farhad Hakimi, Hosain Hakimi
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Patent number: 6356677Abstract: A method introduces variable time offsets into a stream of optical pulses. The method includes receiving a plurality of coherent optical pulses, receiving a plurality of control signals, and forming a coherent pulse array (CPA) from each pulse in response to one of the received control signals. Temporal spacings between pulses of each CPA are responsive to the associated one of the received control signals. For optical control signals, response times can be very short. The method further includes transmitting each pulse through a dispersive optical medium. The act of transmitting makes pulses of each CPA overlap to form an interference pattern.Type: GrantFiled: July 27, 1999Date of Patent: March 12, 2002Assignee: Massachusetts Institute of TechnologyInventors: Katherine L. Hall, Hosain Hakimi, Farhad Hakimi, Daniel T. Moriarty, Kristin A. Rauschenbach
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Publication number: 20020015206Abstract: A method of generating a signal including: generating a first sequence of coherent optical pulses which are sufficiently close in spacing so as to overlap and interfere upon traveling a predetermined length down an optical fiber to form a first interference pattern with a first central lobe having a characteristic wavelength, wherein the energy of the pulses of the first sequence of pulses is within the non-linear regime of the optical fiber; manipulating the first sequence of optical pulses; in a similar manner generating a second sequence of coherent optical pulses; manipulating the second sequence of optical pulses; and introducing both the first and second manipulated sequences of pulses into the optical fiber, wherein the manipulating of the pulses of the first and the second sequence of pulses shifts the characteristic wavelengths of the first and second central lobes, respectively, to first and second transmission signal wavelengths.Type: ApplicationFiled: March 8, 2001Publication date: February 7, 2002Inventors: Farhad Hakimi, Hosain Hakimi
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Patent number: 5915385Abstract: A dental device for removable placement in the mouth of a user for eliminating snoring and relieving stress. The device includes and upper member which is adapted for engagement with the user's upper dentition. An anterior extension suspends downwardly from the upper member and includes an interior surface and an exterior surface. The exterior surface is configured based on the user's jaw and mouth anatomy so that the exterior surface engages at least some of the lower front teeth in the user's mouth. Engagement of the exterior surface of the anterior extension with the user's lower front teeth advances the user's jaw forward with respect to the user's upper jaw such that the user's upper airway is enlarged and the passage of air though the upper airway is facilitated. The interior surface of the anterior extension is advantageously provided with a rough texture for attracting and positioning the tongue in a forward position.Type: GrantFiled: April 2, 1997Date of Patent: June 29, 1999Inventor: Farhad Hakimi
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Patent number: 5587827Abstract: Chromatic and polarization dispersion and transmitter frequency chirp are the dominant data rate limiting factors for high-speed, long distance communication systems. To overcome such limitations, a chromatic and polarization dispersion and frequency chirp compensator is utilized. The applicants provide a compensator by combining a wavelength to polarization transformer with a polarization to delay converter having a dispersion characteristic of substantially equivalent in magnitude, and opposite in sign, to the desired amount of dispersion and frequency chirp to be compensated. Optical gain may be incorporated in any of the elements of the compensator which makes the present invention a lightwave amplifier as well as a dispersion compensator. The present invention is also applicable as an optical pulse time compressor that compresses a relatively long width optical pulse to a short width pulse.Type: GrantFiled: February 1, 1995Date of Patent: December 24, 1996Inventors: Hosain Hakimi, Farhad Hakimi
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Patent number: 5432637Abstract: Apparatus for depolarizing light in fiber optics, comprises of a pair of fiber optic collimators and plurality of contiguous slabs of linear birefringent plates arranged in a stack forming a parallel slab. The optical axes of said linear birefringent plates are approximately 45 degrees with respect to each other. Thicknesses of said linear birefringent plates are such that their individual polarization mode delays exceed coherence time of a beam defined by an optical source.Type: GrantFiled: June 13, 1994Date of Patent: July 11, 1995Inventor: Farhad Hakimi
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Patent number: 5408317Abstract: A scattered light Moire-Brillouin guided wave gyroscope includes a coherent light source for providing two counter-rotating primary waves; an optical waveguide, responsive to the two primary waves, for generating a Moire fringe from a primary fringe and a Brillouin fringe derived respectively from the counter-rotating primary waves and from the counter-rotating Brillouin waves produced from the primary waves; and means for detecting the rotation of the Moire fringe relative to the waveguide.Type: GrantFiled: December 28, 1990Date of Patent: April 18, 1995Assignee: The Charles Stark Draper Laboratory, Inc.Inventors: William A. Dyes, Farhad Hakimi
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Patent number: 5365538Abstract: A slab waveguide pumped channel waveguide laser includes a slab waveguide having a primary pump guiding layer with a first index of refraction and having first and second opposing faces and a peripheral edge including a mirrored surface, and cladding means having a second index of refraction lower than the first index of refraction, proximate the first and second opposing faces; at least one rare earth doped channel waveguide laser having a third index of refraction higher than the first index of refraction disposed in the primary guiding layer; and means for introducing pumping energy into the guiding layer to reflect between the mirror surfaces and energize the laser.Type: GrantFiled: October 29, 1992Date of Patent: November 15, 1994Assignee: The Charles Stark Draper Laboratory Inc.Inventors: Richard Tumminelli, Farhad Hakimi, John R. Haavisto
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Patent number: 5260957Abstract: A quantum dot laser includes a laser host material; a plurality of quantum dots disposed in the host material; and a pumping source for exciting and inducing a population inversion in the quantum dots.Type: GrantFiled: October 29, 1992Date of Patent: November 9, 1993Assignee: The Charles Stark Draper Laboratory, Inc.Inventors: Farhad Hakimi, Moungi G. Bawendi, Richard Tumminelli, John R. Haavisto
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Patent number: 5196041Abstract: A method of forming an optical channel waveguide by gettering includes forming on a substrate a porous waveguide layer containing an index of refraction raising dopant in a compound; sealing a portion of the waveguide layer along a path; and reacting the component, including the index of refraction raising dopant, with a reactant in the unsealed portion of the waveguide layer to form a volatile product from the reactant and dopant to deplete the dopant in the unsealed portion of the waveguide layer and reduce its index of refraction relative to that in the path to produce a channel waveguide along the path.Type: GrantFiled: February 4, 1992Date of Patent: March 23, 1993Assignee: The Charles Stark Draper Laboratory, Inc.Inventors: Richard P. Tumminelli, Farhad Hakimi, John R. Haavisto
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Patent number: 5194079Abstract: A method of forming an optical channel waveguide includes forming on a substrate a waveguide layer of silica doped with an index of refraction raising dopant whose concentration profile in a first dimension includes a higher concentration region and an adjacent lower concentration region; and heating the waveguide layer along two spaced areas defined in the second and third dimension which define a path between them for diffusing the dopant along the first dimension from the higher concentration region to the lower concentration region to reduce the index of refraction of the higher concentration region in portions of the higher concentration region proximate the spaced areas and create a waveguide along the path.Type: GrantFiled: February 4, 1992Date of Patent: March 16, 1993Assignee: The Charles Stark Draper Laboratory, Inc.Inventors: Richard P. Tumminelli, Farhad Hakimi, John R. Haavisto
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Patent number: 5178658Abstract: A method of forming an optical waveguide which includes the steps of forming on a substrate a waveguide layer including at least one host medium and one dopant medium, one of which is more volatile than the other; and heating the waveguide layer to selectively volatize the more volatile medium along a path, raising the index of refraction and creating a waveguide along the path.Type: GrantFiled: September 17, 1991Date of Patent: January 12, 1993Assignee: The Charles Stark Draper Laboratory, Inc.Inventors: Richard P. Tumminelli, Farhad Hakimi, John R. Haavisto
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Patent number: 5166940Abstract: A fiber optic laser includes a fiber optic element, and a Bragg grating means in the fiber optic element and defined by a periodic variation in the index of refraction of the element to enhance the narrow band response of the laser and/or increase the loss of unwanted frequencies. A method of making the fiber laser is also disclosed.Type: GrantFiled: June 4, 1991Date of Patent: November 24, 1992Assignee: The Charles Stark Draper Laboratory, Inc.Inventors: Richard P. Tumminelli, Farhad Hakimi, Robert P. Dahlgren
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Patent number: 5121460Abstract: An optical fiber includes a multimode primary core having an index or refraction N.sub.1 and doped with a material providing optical gain; the cladding surrounding the core having an index of refraction N.sub.2 ; and a secondary core doped with an absorbent material for providing optical loss in unwanted modes.Type: GrantFiled: January 31, 1991Date of Patent: June 9, 1992Assignee: The Charles Stark Draper Lab., Inc.Inventors: Richard P. Tumminelli, Farhad Hakimi
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Patent number: 5064288Abstract: A scattered light multi-Brillouin guided wave optical gyroscope includes a coherent light source; an optical waveguide responsive to the coherent light source for generating a Brillouin, inertially stationary, synchronized fringe from two counter-rotating fringes each derived from a pair of Brillouin waves separated by twice the Brillouin shift; and means for detecting relative rotation between the Brillouin stationary synchronized fringe and the waveguide.Type: GrantFiled: December 7, 1990Date of Patent: November 12, 1991Assignee: The Charles Stark Draper LaboratoryInventors: William A. Dyes, Farhad Hakimi
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Patent number: 4815079Abstract: Apparatus for coupling radiation into a single-mode core of an optical fiber laser has a single-mode core disposed within a relatively large, multimode cladding at a location which is displaced from the center of the cross-section of the cladding. The cladding is surrounded by a further layer to prevent radiation from propagating out of the cladding. In addition, the apparatus preferably has slight bends to enhance the coupling of radiation from the cladding into the single-mode core. A further embodiment has a single-mode fiber laser disposed in a relatively large, multimode, slab cladding which, in turn, is surrounded by another cladding to prevent radiation from propagating out of the large cladding.Type: GrantFiled: December 17, 1987Date of Patent: March 21, 1989Assignee: Polaroid CorporationInventors: Elias Snitzer, Hong Po, Richard P. Tumminelli, Farhad Hakimi
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Patent number: 4680767Abstract: An optical fiber laser comprising a gain cavity in the form of a single mode optical fiber with integrally formed reflective end sections for provision of feedback. One end section is an etalon for modifying the gain cavity resonant characteristics and intensity modulation, and the other end section is used to alter gain cavity effective length to tune and frequency modulate. The emission spectrum of the laser gain material, which is preferably neodymium oxide incorporated in a silicate glass core, along with the etalon section reflection, pump energy level, and gain cavity length cooperate so that lasing takes place over just a single line of narrow width or over more than one line within a narrow band. Electro-optic material in the end sections permit output frequency and amplitude to be selectively activated in response to the application of applied voltages.Type: GrantFiled: July 1, 1985Date of Patent: July 14, 1987Assignee: Polaroid CorporationInventors: Farhad Hakimi, Hong Po, Elias Snitzer