Frequency Modulation Patents (Class 359/278)
  • Patent number: 7853153
    Abstract: The present invention is to provide an optical modulating system for generating a signal of a frequency (f0+2fm) and a signal of a frequency (f0?2fm) and suppressing a signal of a frequency (f0) by a DSB-SC modulator. A fourth harmonic generating system for solving the above problem comprises a first DSB-SC modulator (2) a second DSB-SC modulator (3) and a signal control section (5) for controlling a modulating signal from a signal source (4) for generating modulating signals applied to the first and second DSB-SC modulators (2,3) so that a lower side-band signal (f0) generated by modulating the upper side-band signal of the DSB-SC modulator (2) by the DSB-SC modulator (3) and an upper side-band signal (f0) generated by modulating the lower side-band signal of the DSB-SC modulator (2) by the DSB-SC modulator (3) cancel each other.
    Type: Grant
    Filed: August 8, 2006
    Date of Patent: December 14, 2010
    Assignee: National Institute of Information and Communications Technology
    Inventors: Tetsuya Kawanishi, Masayuki Izutsu, Takahide Sakamoto, Masahiro Tsuchiya
  • Publication number: 20100278474
    Abstract: A device includes a resonator capable of supporting a plasmon mode, a gain structure arranged to couple energy into the resonator, and a memristive layer arranged to provide an interaction with the plasmon mode. An electric signal applied to the memristive layer can change the interaction and change a resonant frequency of the plasmon mode.
    Type: Application
    Filed: April 30, 2009
    Publication date: November 4, 2010
    Inventors: Raymond G. Beausoleil, Sagi V. Mathal, Alexandre M. Bratkovski
  • Patent number: 7724413
    Abstract: Provided are a speckle removing light source capable of removing speckle by using laser light whose wavelength is temporally changed and a lighting apparatus for producing an image from which the speckle is removed. Included are a light source for outputting laser light, and a light frequency modulator for temporally changing a wavelength of the laser light. The light frequency modulator has a predetermined period set for changing the wavelength of the laser light. Also, provided is a lighting apparatus, including a spatial light modulator illuminated with the laser light outputted from the speckle removing light source to produce an image. The spatial light modulator has a period set for producing the image, which is longer than the period for changing the wavelength of the laser light by the light frequency modulator.
    Type: Grant
    Filed: July 11, 2005
    Date of Patent: May 25, 2010
    Assignee: Mitsubishi Electric Corporation
    Inventors: Yasuharu Koyata, Yoshihito Hirano, Kiyohide Sakai, Masao Imaki, Shinsuke Shikama, Jiro Suzuki, Takao Endou, Kouhei Teramoto, Shigenori Shibue
  • Patent number: 7697186
    Abstract: An optical system comprising a frequency modulated laser source adapted to produce a frequency modulated optical beam, an optical spectrum reshaper (OSR) adapted to receive the frequency modulated optical beam from the laser source and convert it into an amplitude modulated optical beam, a focusing lens adapted to receive the amplitude modulated optical beam from the OSR and focus the same, and an optical fiber adapted to receive the amplitude modulated optical beam from the focusing lens and transmit an optical signal; characterized in that the OSR has a central axis, the focusing lens has a central axis, and the optical fiber has a central axis, with the central axis of the optical fiber being laterally offset from at least one of the central axis of the OSR and the central axis of the focusing lens so as to effect spatial filtering and thereby generate the desired optical transmission characteristics for the resulting optical signal in the optical fiber.
    Type: Grant
    Filed: October 24, 2007
    Date of Patent: April 13, 2010
    Assignee: Finisar Corporation
    Inventors: Kevin McCallion, Daniel Mahgerefteh, Michael Deutsch, Parviz Tayebati
  • Publication number: 20100073755
    Abstract: A wavelength conversion device enabling the stable output of high-power harmonic light is disclosed. The wavelength conversion device includes MgO:LiNbO3 (PPMgLN) having a periodic polarization reversed structure, and the +Z and ?Z surfaces of the PPMgLN are covered with thin chrome (Cr) film. In the PPMgLN, the incident surface and output surface are disposed on the ?X side and +X side, respectively, in the longitudinal direction. Because of this structure, even when a high-power laser fundamental wave is incident, the PPMgLN can avoid destruction and damage due to the electric field, thereby enabling the stable output of high-power harmonic.
    Type: Application
    Filed: February 6, 2008
    Publication date: March 25, 2010
    Inventors: Yasuhiro Higashi, Yasuhiro Satoh
  • Publication number: 20100067091
    Abstract: One exemplary metamaterial is formed from a plurality of individual unit cells, at least a portion of which have a different permeability than others. The plurality of individual unit cells are arranged to provide a metamaterial having a gradient index along at least one axis. Such metamaterials can be used to form lenses, for example.
    Type: Application
    Filed: April 15, 2009
    Publication date: March 18, 2010
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: David R. Smith, David Schurig, Anthony F. Starr, Jack J. Mock
  • Patent number: 7639910
    Abstract: An optical module is configured with a combination of a single-mode oscillating light source and an optical filter. In this optical module, the single-mode oscillating light source outputs a single-mode, frequency-modulated signal. Further, the optical filter converts the frequency modulation to an amplitude modulation. And, the single-mode oscillating light source and the optical filter are packaged without active alignment on the same substrate. Accordingly, it is possible to realize an optical module in a simple and low-cost configuration by packaging the single-mode oscillating light source and the optical filter by passive alignment, without active alignment, on the same substrate, and by using a simple optical filter such as a waveguide ring resonator, which converts a frequency modulation to an amplitude modulation.
    Type: Grant
    Filed: June 6, 2007
    Date of Patent: December 29, 2009
    Assignee: NEC Corporation
    Inventors: Hiroyuki Yamazaki, Takaaki Hatanaka
  • Publication number: 20090268271
    Abstract: An apparatus for shifting the frequency of light comprises a modulator comprising one or more light-reflective elements. The elements are arranged in N groups that are interleaved along the surface of the modulator. The elements are deflected in time in a periodic sawtooth or sinusoidal N-phase manner. The frequency shift can be varied continuously and quickly. Such a modulator may be operated at zero frequency shift, to produce an optical phase shift.
    Type: Application
    Filed: February 9, 2009
    Publication date: October 29, 2009
    Inventor: Meritt Reynolds
  • Publication number: 20090244684
    Abstract: A laser projection system including a system controller, a visible light source, and a light disrupting element is provided. The visible light source includes at least one laser and the laser projection system is programmed to scan a scanned optical signal of the visible light source across a plurality of image pixels. The scanned optical signal comprises a low spatial frequency beam and a high spatial frequency beam, and the low spatial frequency beam generates a low spatial frequency image having spatial frequencies below a spatial frequency threshold, the high spatial frequency beam generates a high spatial frequency image having spatial frequencies that are above the spatial frequency threshold, and the scanned laser image is a sum of the high spatial frequency image and the low spatial frequency image. The low spatial frequency beam is altered by an out of focus light disrupting element.
    Type: Application
    Filed: March 27, 2008
    Publication date: October 1, 2009
    Inventor: Jacques Gollier
  • Publication number: 20090190200
    Abstract: There is provided an optical device including a plurality of polarizers that are arranged along a propagation direction of incident light, where the plurality of polarizers have transmission axes of substantially the same direction, a phaser that is provided between the plurality of polarizers, where the phaser has a retarded-phase axis forming a predetermined angle with the transmission axes of the plurality of polarizers, and a phase modulator that is provided adjacent to the phaser along the propagation direction, where the phase modulator has a retarded-phase axis of substantially the same direction as the retarded-phase axis of the phaser. Here, a phase difference generated in the incident light by the phase modulator is temporally adjusted such that the optical device transmits light in different wavelength ranges at different timings.
    Type: Application
    Filed: January 8, 2009
    Publication date: July 30, 2009
    Applicant: FUJIFILM CORPORATION
    Inventors: Takashi Murooka, Hideyasu Ishibashi, Ichiro Amimori
  • Patent number: 7538935
    Abstract: A technique for generating variable pulse delays uses one or more nonlinear-optical processes such as cross-phase modulation, cross-gain modulation, self-phase modulation, four-wave mixing or parametric mixing, combined with group-velocity dispersion. The delay is controllable by changing the wavelength and/or power of a control laser. The delay is generated by introducing a controllable wavelength shift to a pulse of light, propagating the pulse through a material or an optical component that generates a wavelength dependent time delay, and wavelength shifting again to return the pulse to its original wavelength.
    Type: Grant
    Filed: March 17, 2006
    Date of Patent: May 26, 2009
    Assignee: Cornell Research Foundation, Inc.
    Inventors: Alexander Gaeta, Jay E. Sharping, Chris Xu
  • Publication number: 20090103163
    Abstract: In order to provide a reciprocating optical modulation system capable of obtaining a broad bandwidth, a reciprocating optical modulation system (1) of the present invention is basically provided with an optical modulator (2) modulating an output light by controlling one of an intensity, a phase and a frequency of an input light; a first fiber grating (3) transmitting a light of a predetermined frequency domain among lights inputted to and outputted from the optical modulator while reflecting lights of other frequencies; a second fiber grating (4) transmitting a light of a predetermined frequency domain among lights inputted to and outputted from the optical modulator while reflecting lights of other frequencies; and a signal source (5) generating a modulating signal to be inputted to the optical modulator (2).
    Type: Application
    Filed: August 9, 2006
    Publication date: April 23, 2009
    Applicant: National Institute of Information and Communivations Technology
    Inventors: Tetsuya Kawanishi, Masayuki Izutsu, Takahide Sakamoto, Masahiro Tsuchiya
  • Publication number: 20090103924
    Abstract: The present invention is to provide an optical modulating system for generating a signal of a frequency (f0+2fm) and a signal of a frequency (f0?2fm) and suppressing a signal of a frequency (f0) by a DSB-SC modulator. A fourth harmonic generating system for solving the above problem comprises a first DSB-SC modulator (2) a second DSB-SC modulator (3) and a signal control section (5) for controlling a modulating signal from a signal source (4) for generating modulating signals applied to the first and second DSB-SC modulators (2,3) so that a lower side-band signal (f0) generated by modulating the upper side-band signal of the DSB-SC modulator (2) by the DSB-SC modulator (3) and an upper side-band signal (f0) generated by modulating the lower side-band signal of the DSB-SC modulator (2) by the DSB-SC modulator (3) cancel each other.
    Type: Application
    Filed: August 8, 2006
    Publication date: April 23, 2009
    Inventors: Tetsuya Kawanishi, Masayuki Izutsu, Takahide Sakamoto, Masahiro Tsuchiya
  • Publication number: 20090022445
    Abstract: Systems and methods for manipulating light with high index contrast waveguides clad with substances having that exhibit large nonlinear electro-optic constants ?2 and ?3. Waveguides fabricated on SOI wafers and clad with electro-optic polymers are described. Embodiments of waveguides having slots, electrical contacts, and input waveguide couplers are discussed. Waveguides having closed loop structures (such as rings and ovals) as well as linear or serpentine waveguides, are described. Optical signal processing methods, such as optical rectification and optical modulation, are disclosed. Designs having responsivity of less than 1 volt-centimeter are described.
    Type: Application
    Filed: May 8, 2008
    Publication date: January 22, 2009
    Applicant: California Institute of Technology
    Inventors: Michael J. Hochberg, Tom Baehr-Jones, Axel Scherer
  • Publication number: 20080266640
    Abstract: A structure includes a film having a plurality of nanoapertures and a semiconductor layer in connection with the film. The nanoapertures are configured to allow the transmission of a predetermined subwavelength of light through the film via the plurality of nanoapertures. The semiconductor layer facilitates the modulation of the predetermined subwavelength of light transmitted through the film.
    Type: Application
    Filed: April 26, 2007
    Publication date: October 30, 2008
    Inventors: Shih-Yuan Wang, Alexandre M. Bratkovski
  • Patent number: 7440642
    Abstract: An integrated optical modulator and method for manufacturing thereof are disclosed. The integrated optical modulator comprises a carrier wave band modulator using a double sideband modulation method and an intermediate frequency band modulator using a single sideband modulation method. The carrier wave band modulator and the intermediate frequency band modulator are connected in series. A method for manufacturing an integrated optical modulator comprises preparing a substrate having at least one polarization reversed section, forming a first optical waveguide part and a second optical waveguide part on the substrate, forming a buffer layer over the first and second optical waveguide parts, forming sequentially a first electrode part and a second electrode part over the first optical waveguide part, and forming a third electrode part over the second optical waveguide part.
    Type: Grant
    Filed: December 15, 2005
    Date of Patent: October 21, 2008
    Assignee: Korea Electronics Technology Institute
    Inventors: Woo Kyung Kim, Woo Seok Yang, Han Young Lee, Hyung Man Lee
  • Patent number: 7418205
    Abstract: An optical spread spectrum communication system includes a tunable laser which sequentially outputs optical signals having different wavelengths. The laser produces a frequency spectrum having a plurality of closely spaced modes relative to optical frequencies. The system further includes an optical modulator and a frequency synthesizer. The frequency synthesizer controls the optical modulator to allow specific modes from the frequency spectrum to pass through. Additionally, the system includes a tunable filter and a phase locked loop (PLL) control circuit. The PLL control circuit controls the filter to select specific channels. The selection of the specific modes by the modulator and the selection of channels by the tunable filter are performed independent of each other and are based on randomly assigned codes generated in accordance with one or more algorithms.
    Type: Grant
    Filed: March 25, 2003
    Date of Patent: August 26, 2008
    Assignee: General Instrument Corporation
    Inventor: Kerry I. Litvin
  • Publication number: 20080170285
    Abstract: In a laser display that displays a video by scanning a beam from a laser light source two-dimensionally on a screen, the image quality being displayed is deteriorated markedly by speckle noises induced from coherency of the light source. A method for oscillating the screen to remove the speckles has problems that a large-scale device is necessary and the screen cannot be chosen without any restrain. A speckle pattern being generated is changed at a high speed by oscillating a light spot on the screen at a high speed using beam oscillation means 3, so that the viewer acknowledges time-mean image having no speckle noises.
    Type: Application
    Filed: February 24, 2005
    Publication date: July 17, 2008
    Inventors: Ken'ichi Kasazumi, Kiminori Mizuuchi, Kazuhisa Yamamoto
  • Patent number: 7391550
    Abstract: Techniques for producing an optical broadband frequency sweep or chirp, include generating a narrowband frequency chirp and a frequency-shifted replica. The narrowband chirp has an optical carrier frequency, a pulse duration and a pulse bandwidth. A frequency-shifted replica is generated by frequency shifting the narrowband chirp by a frequency shift. Adding the frequency-shifted replica after a start of the narrowband chirp by a delay generates a broadband frequency chirp. Alternatively, the frequency-shifted replica is generated by frequency shifting a constant frequency pulse, and modulating the frequency-shifted pulse to generate narrowband chirps that are added to form the broadband chirp.
    Type: Grant
    Filed: May 6, 2004
    Date of Patent: June 24, 2008
    Assignee: Montana State University
    Inventors: Todd Harris, Kristian Merkel
  • Patent number: 7391978
    Abstract: The invention provides an optical signal transmitter low in noise and in distortion and provides an optical signal transmission system using this optical signal transmitter. The optical signal transmitter includes a plurality of frequency modulation means for distributing an electric signal into a plurality of electric signals and applying frequency modulation to the distributed electric signals to output and a multiplexing mean for multiplexing a plurality of signals output from the plurality of frequency modulation means and outputting a multiplexed signal. The plurality of frequency modulation means are set to be substantially equal to each other in frequency deviation and in intermediate frequency and to be substantially identical to each other in the phase of each output.
    Type: Grant
    Filed: July 9, 2004
    Date of Patent: June 24, 2008
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventor: Koji Kikushima
  • Patent number: 7379652
    Abstract: Techniques for detecting optical spectral properties of a target are described. The technique includes providing an optical carrier which has an optical frequency bandwidth which is narrow compared to the width of the narrowest spectral feature of the target to be determined. This optical carrier is then electro-optically modulated with an RF frequency chirp, creating an optical chirp probe beam with a frequency chirped optical spectrum having upper and lower frequency chirped sidebands that have amplitudes sufficient to be detected at a detector. The sidebands are frequency bands arranged symmetrically around the optical carrier frequency. The attributes of a sideband include a start frequency, bandwidth and chirp rate. A probe beam is generated with the sidebands and directed onto a target having a physical property with optical frequency dependence. An optical response signal resulting from an interaction between the probe beam and the target is detected.
    Type: Grant
    Filed: April 14, 2006
    Date of Patent: May 27, 2008
    Assignee: Montana State University
    Inventors: Zachary Cole, Randy R. Reibel, Krishna Mohan Rupavatharam, William R. Babbitt, Kristian D. Merkel, Tiejun Chang
  • Patent number: 7376358
    Abstract: An optical spike is generated at an arbitrarily selected location within an arbitrary optical link. The optical spike is generated by deriving a spike signal having a plurality of components, and launching the spike signal into the a transmitter end of the optical link. An initial phase relationship between the components is selected such that the involved signal components will be phase aligned at the selected location. In order to achieve this operation, the initial phase relationship between the components may be selected to offset dispersion induced phase changes between the transmitter end of the link and the selected location. One or more optical spikes can be generated at respective arbitrarily selected locations within the link, and may be used for performance monitoring, system control, or other purposes.
    Type: Grant
    Filed: October 3, 2003
    Date of Patent: May 20, 2008
    Assignee: Nortel Networks Limited
    Inventors: Kim Roberts, Maurice O'Sullivan
  • Patent number: 7310181
    Abstract: An optical deflection device includes an optical deflection element having a pair of transparent boards arranged in a mutually opposing manner. A liquid crystal layer is filled between the boards and forms a chiral smectic C phase. An orientation film orients liquid crystal molecules in the liquid crystal layer in a substantially perpendicular direction with respect to the liquid crystal layer. Electrodes generate an electric field in a substantially parallel direction with respect to the liquid crystal layer. A first voltage application part applies, to the electrodes, an ac voltage of a deflection frequency switching the optical deflection direction of the optical deflection element. A second voltage application part applies, to the electrodes, an ac voltage of a higher frequency than the deflection frequency.
    Type: Grant
    Filed: January 4, 2006
    Date of Patent: December 18, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Yumi Matsuki, Hiroyuki Sugimoto, Toshiaki Tokita, Shigeaki Nimura, Masanori Kobayashi, Yasuyuki Takiguchi
  • Patent number: 7292751
    Abstract: An optical filter includes at least one waveguide structure. The optical filter also includes a plurality of optical resonators that are aligned in an coupled arrangement with the at least one waveguide structure so as to produce an asymmetric distribution of coupling coefficients.
    Type: Grant
    Filed: January 11, 2006
    Date of Patent: November 6, 2007
    Assignee: Massachusetts Institute of Technology
    Inventor: Milos Popovic
  • Patent number: 7224506
    Abstract: A single side band modulation device includes a first Mach Zehnder interferometer and a second Mach Zehnder interferometer. The first Mach Zehnder interferometer includes at least two output arms, and the second Mach Zehnder interferometer includes at least two output arms. Terminals of the output arms are connected with one another.
    Type: Grant
    Filed: February 23, 2006
    Date of Patent: May 29, 2007
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Sung-Kee Kim, Hoon Kim, Han-Lim Lee, Seong-Taek Hwang
  • Patent number: 7180648
    Abstract: An electro-absorption light intensity modulator device is provided that comprises a first and a second layer disposed relative to the first layer so as to provide a light-absorbing optical confinement region. The first layer comprises a first insulator layer, and the light-absorbing optical confinement region comprises at least one quantum-confined structure. The at least one quantum-confined structure possesses dimensions such, that upon an application of an electric field in the at least one quantum-confined structure, light absorption is at least partially due to a transition of at least one carrier between a valence state and a conduction state of the at least one quantum-confined structure. A method is also provided for fabricating an electro-absorption light intensity modulator device.
    Type: Grant
    Filed: June 13, 2005
    Date of Patent: February 20, 2007
    Assignee: Massachusetts Institute of Technology
    Inventors: Carl Dohrman, Saurabh Gupta, Eugene A. Fitzgerald
  • Patent number: 7126739
    Abstract: A method and apparatus for characterizing light from an optical source using simplified chronocyclic tomography by modulating the phase of light from an optical source using alternating positive and negative quadratic temporal phase modulation at a desired alternating frequency ?; generating an electric signal proportional to the optical power of the modulated light after propagation through an optical frequency resolving device, for a desired optical frequency ?; determining a time-invariant and time-varying components of the electric signal; repeating the generating and determining steps for a plurality of optical frequencies; and determining the spectral phase and spectral intensity of the light from the optical source using the time-invariant and time-varying components determined for the plurality of optical frequencies.
    Type: Grant
    Filed: February 28, 2005
    Date of Patent: October 24, 2006
    Assignee: Lucent Technologies Inc.
    Inventors: Christophe J Dorrer, Inuk Kang
  • Patent number: 7102755
    Abstract: A method determines power of a modulated signal that is applied to a wavelength meter by summing bin values within a designated bin range of a frequency transformed interferogram representing the modulated signal and provided by the wavelength meter. In a first embodiment of the method, the bin range within which the bin values are summed is designated by mapping a series of signal characteristics indicative of the types of the modulated signals applied to the wavelength meter, to a series of bin spans within the frequency transformed interferograms that represent the modulated signals. The method then enables a selection of a signal characteristic from the series of signal characteristics to identify the modulated signal that is applied to the wavelength meter.
    Type: Grant
    Filed: February 22, 2002
    Date of Patent: September 5, 2006
    Assignee: Agilent Technologies, Inc.
    Inventors: David M Braun, Misty J Mesel
  • Patent number: 7092643
    Abstract: The optical transmission apparatus has a Mach-Zehnder optical modulator, a light source for applying an optical signal of a continuous light to the optical modulator, a driving circuit for inputting a driving signal into the optical modulator, a branching filter for taking out a part of an output optical signal, a photodiode for converting the taken-out output optical signal into an electric signal, a band pass filter for extracting a frequency component of a driving signal included in this electric signal, an error signal generator circuit for generating an error signal of a bias voltage that minimizes a value of the extracted frequency component, and a bias voltage control circuit for applying a bias voltage added with this error signal to the optical modulator.
    Type: Grant
    Filed: June 28, 2001
    Date of Patent: August 15, 2006
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Satoshi Kajiya, Kazuyuki Ishida, Katsuhiro Shimizu, Yukio Kobayashi
  • Patent number: 7068412
    Abstract: With respect to the relative intensity noise (RIN) for inputs to an optical modulator or the signal-to-noise ratio (SNR) for outputs therefrom, the optical modulator modulating coherent lights of different wavelengths obtained by slicing a spectrum of the multi-wavelength light, the shape of a spectrum of a multi-wavelength light is controlled so that predetermined RIN and SNR can be obtained in accordance with transmission system parameters (the type and distance of optical fibers, the number of repeaters), thus enabling design meeting a performance specification for a conventional transmission section using semiconductor lasers.
    Type: Grant
    Filed: April 16, 2004
    Date of Patent: June 27, 2006
    Assignee: Nippon Telegraph and Telephone Corp.
    Inventors: Masamichi Fujiwara, Katsuhiro Araya, Mitsuhiro Teshima, Junichi Kani, Kenichi Suzuki
  • Patent number: 7046414
    Abstract: An optical modulator is driven by applying, to a first signal electrode, an amplitude-modulated input driving signal waveform, which has a pair of same phase envelope lines, and which has a full width smaller than a potential difference between adjacent two of bias voltages at which an optical intensity of an intensity-modulated output optical signal from the optical modulator takes a minimum value or between adjacent two of other bias voltages at which the optical intensity takes a maximum value.
    Type: Grant
    Filed: December 13, 2002
    Date of Patent: May 16, 2006
    Assignee: NEC Corporation
    Inventor: Risato Ohhira
  • Patent number: 7023601
    Abstract: A method for modulating the E-field of an optical carrier signal utilizes a Mach-Zehnder modulator having a pair of independently controllable branches. A pair of independent branch drive signals VL(t) and VR(t) are derived. Each branch of the MZ modulator is driven with a respective one of the independent branch drive signals. By this means, a low cost conventional MZ modulator (interferometer) can be used to perform complex modulation of the E-field of the optical carrier. In some embodiments, this functionality is used to facilitate precompensation of optical impairments of an optical communications system.
    Type: Grant
    Filed: October 3, 2003
    Date of Patent: April 4, 2006
    Assignee: Nortel Networks Limited
    Inventors: Douglas McGhan, Maurice O'Sullivan, Yves Beaulieu
  • Patent number: 7024056
    Abstract: The device includes an oscillator (1) to generate an electrical signal of a predetermined frequency and a signal divider (2) to split the electrical signal into first and second signals. The frequency of the second signal is tripled by tripler (3) and the tripled second signal is recombined with the first signal at signal adder (9) to produce a combined electrical signal. This combined electrical signal drives a Mach-Zehnder modulator (10).
    Type: Grant
    Filed: March 1, 2002
    Date of Patent: April 4, 2006
    Assignee: Bookham Technology, plc
    Inventor: Robert Griffin
  • Patent number: 6965479
    Abstract: A first optical system (11) has a first beam splitter (211). The first beam splitter (211) splits light arriving through a first optical path (P1) into two light beams, and outputs one light beam to a second optical path (P2) and the other light beam to a third optical path (P3). A second optical system (21) outputs the light output from the first beam splitter (221) to the second optical path (P2) and arriving at the second optical system (21) upon giving the light an intensity change with wavelength dependence and a phase change, and has a second beam splitter (221), first reflecting mirror (223), and second reflecting mirror (222). This makes it possible to provide an optical filter (200) which can realize a characteristic excellent in isolation with a very simple arrangement.
    Type: Grant
    Filed: December 10, 2002
    Date of Patent: November 15, 2005
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Tomomi Sano, Hiroshi Suganuma, Tamoya Kenmochi, Tetsuya Iimura, Manabu Shiozaki
  • Patent number: 6906309
    Abstract: A multi-tone photonic oscillator comprises a laser; an optical modulator coupled to the laser; and a delay line and a photodetector coupled to the optical modulator for generating a delayed electrical signal representation of the output of the optical modulator; wherein the optical modulator being responsible for the delayed electrical signal for generating multiple tones where the frequency intervals of the tones is a function of the amount of delay imposed by the delay line.
    Type: Grant
    Filed: April 5, 2002
    Date of Patent: June 14, 2005
    Assignee: HRL Laboratories, LLC
    Inventors: Keyvan Sayyah, Daniel Yap
  • Patent number: 6885490
    Abstract: A method and apparatus for characterizing an optical pulse using a reduced complexity chronocyclic tomography is described. In one example, an optical pulse train is modulated using quadratic temporal phase modulation. A first spectral intensity of the optical pulse train is measured after a quadratic temporal phase modulation having a first amplitude. A second spectral intensity of the train of optical pulses is then measured in response to the quadratic temporal phase modulation having a second amplitude. At least one of the group delay and the spectral intensity associated with the train of optical pulses is computed using the first spectral intensity and the second spectral intensity.
    Type: Grant
    Filed: May 1, 2003
    Date of Patent: April 26, 2005
    Assignee: Lucent Technologies Inc.
    Inventors: Christophe J. Dorrer, Inuk Kang
  • Patent number: 6834134
    Abstract: A method and apparatus are provided for generating short (e.g., picosecond) pulses using a 2 section 1553 nm DBR laser without gain switching nor external modulation. The center wavelength of the DBR section is modulated at 0.5 GHz to generate a constant amplitude frequency modulated optical wave Large group velocity dispersion is then applied with a chirped fiber Bragg grating to convert the FM signal to a pulse stream.
    Type: Grant
    Filed: March 23, 2001
    Date of Patent: December 21, 2004
    Assignee: 3M Innovative Properties Company
    Inventors: James F. Brennan, III, Patrick C. Chou, Harry L. T. Lee, Rajeev J. Ram, Hermann A. Haus, Erich P. Ippen
  • Patent number: 6816299
    Abstract: A method and system for optimization of an optical transmissions signal which is modulated with a binary data signal, wherein a control device ensures that the operating point and the modulation signal of a Mach-Zehnder modulator are set optimally, with the fundamental frequency and/or the first harmonic frequency of the transmission signal being selected for this purpose, and an optimum setting is reached when the amplitude of the fundamental frequency has reached a maximum value and the amplitude of the harmonic frequency has reached a minimum value.
    Type: Grant
    Filed: August 7, 2002
    Date of Patent: November 9, 2004
    Assignee: Siemens Aktiengesellschaft
    Inventors: Christoph Glingener, Erich Gottwald
  • Patent number: 6768570
    Abstract: Desired characteristic impedance can be obtained in an optical modulator. The optical modulator includes a substrate having the electrooptic effect; an optical waveguide formed on a surface of the substrate; and a signal electrode and a ground electrode formed in the vicinity of the optical waveguide, wherein the signal electrode and the ground electrode include an interaction portion and an extraction portion, and a groove is formed between the signal electrode and the ground electrode located in the extraction portion area.
    Type: Grant
    Filed: February 21, 2003
    Date of Patent: July 27, 2004
    Assignee: Fujitsu Limited
    Inventors: Masaki Sugiyama, Tadao Nakazawa
  • Patent number: 6762882
    Abstract: An imaging system is disclosed that includes an illumination source, a modulator and a variable Fourier diaphragm. The illumination source produces a first illumination field having a first frequency and a second illumination field having a second frequency. The modulator receives the first illumination field and the second illumination field, and produces a first modulated illumination field and a second modulated illumination fields. The variable Fourier diaphragm selectively passes one of the first modulated illumination field and the second modulated illumination field.
    Type: Grant
    Filed: November 14, 2002
    Date of Patent: July 13, 2004
    Assignee: Agfa COrporation
    Inventors: Volker Melzer, Tobias Damm, Peter Mueller, Ralph Thoma
  • Patent number: 6751001
    Abstract: A device for the passive conversion of one format to another includes: a laser light source at a predetermined frequency, a line converter configured to produce a fan of light, a movable lens configured to collimate the fan of light, and an array of light modulators placed such that the collimated light is incident on a portion of the light modulators. Vertical pixels of an input image are reproduced on either 1, 2, 3, etc, adjacent light modulators depending on the target image size to produce a modulated light column. Any discrepancy between the modulated light column height and the target image height is compensated for using a zoom lens. The modulated light column is then reflected to a display surface. An entire image is produced by changing the state of the array of light modulators to correspond with each of the vertical columns of the image and sweeping the vertical columns across the display surface.
    Type: Grant
    Filed: January 24, 2003
    Date of Patent: June 15, 2004
    Assignee: Evans & Sutherland Computer Corporation
    Inventors: Allen H. Tanner, Aaron S. McAllister
  • Patent number: 6746618
    Abstract: The present invention provides an electro-optic ceramic material including lead, zinc and niobium having a propagation loss of less than about 3 dB/cm and a quadratic electro-optic coefficient of greater than about 1×10−6 m2/V2 at 20° C. at a wavelength of 1550 nm. The present invention also provides electro-optic devices including an electro-optic ceramic material including lead, zinc and niobium having a propagation loss of less than about 3 dB/cm and a quadratic electro-optic coefficient of greater than about 1×10−16 m2 V at 20° C. at a wavelength of 1550 nm. The materials and devices of the present invention are useful in optical communications applications such as intensity and phase modulation, switching, and polarization control.
    Type: Grant
    Filed: May 21, 2002
    Date of Patent: June 8, 2004
    Assignee: Corning Incorporated
    Inventors: Kewen K. Li, Qingwu Wang
  • Patent number: 6744547
    Abstract: A nonlinear optical crystal device, a wavelength conversion element, is surrounded with a heat sink having cooling fins. Cartridge heaters for uniformly heating the nonlinear optical crystal device are arranged in the heat sink, and the temperature of the cartridge heater is regulated by a heater controller. Laser light is input into the nonlinear optical crystal device, and delivered therefrom after its wavelength is converted into a shortened wavelength. When the repetition frequency of laser light is high, heating by the heaters is stopped, and cooling is effected with the heat sink. When the repetition frequency of laser light is low, heating by the heaters is carried out to maintain the temperature of the nonlinear optical crystal device to be a temperature at which a conversion efficiency is satisfactory.
    Type: Grant
    Filed: December 19, 2001
    Date of Patent: June 1, 2004
    Assignee: Mitsubishi Heavy Industries, Ltd.
    Inventors: Naoaki Ikeda, Takashi Akaba, Osamu Noda, Susumu Miki, Yuichi Ohtani
  • Patent number: 6711309
    Abstract: An optical communications system comprises, among other things, a laser source; an optical waveguide interconnected to the laser source to carry an optical signal from the source to an optical receiver; an optical receiver interconnected to the optical waveguide for decoding the signal; and a mechanical modulator adapted to substantially continuously mechanically perturb a portion of the optical waveguide so as to reduce Rayleigh backscattering from the optical waveguide.
    Type: Grant
    Filed: October 30, 2001
    Date of Patent: March 23, 2004
    Assignees: The University of Sydney, Telstra Corporation Limited, The University of Melbourne
    Inventors: Hongbing Gan, Arthur James Lowery, Richard David Lauder, Mark Sceats
  • Patent number: 6667826
    Abstract: A system for providing high-resolution color separation in electronic imaging. Comb drives controllably oscillate a red-green-blue (RGB) color strip filter system (or otherwise) over an electronic imaging system such as a charge-coupled device (CCD) or active pixel sensor (APS). The color filter is modulated over the imaging array at a rate three or more times the frame rate of the imaging array. In so doing, the underlying active imaging elements are then able to detect separate color-separated images, which are then combined to provide a color-accurate frame which is then recorded as the representation of the recorded image. High pixel resolution is maintained. Registration is obtained between the color strip filter and the underlying imaging array through the use of electrostatic comb drives in conjunction with a spring suspension system.
    Type: Grant
    Filed: March 1, 2002
    Date of Patent: December 23, 2003
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Frank T. Hartley, Anthony B. Hull
  • Patent number: 6643470
    Abstract: An FM signal converter comprising: an amplitude detecting unit for detecting amplitude variation of a plurality of signals that are multiplexed with subcarriers, as an amplitude variation signal; a peak detection unit for determining from said amplitude variation signal whether a peak of the amplitude of said plurality of signals exceeds a threshold and for generating peak detection information that includes information about said peak of the amplitude; a frequency signal source for providing signal with a predetermined frequency that differs from any of the frequencies of said subcarriers; an amplitude phase control unit for adjusting amplitude and phase of the signal from the frequency signal source according to said peak detecting information and outputting the adjusted signal as a corrected signal; signal combining means for combining said corrected signal and said plurality of signals multiplexed with subcarriers, with considering a time for generating the corrected signal; and an FM modulator for
    Type: Grant
    Filed: September 28, 2000
    Date of Patent: November 4, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masanori Iida, Hisashi Adachi, Hiroyuki Asakura
  • Publication number: 20030174379
    Abstract: The present invention relating to a device and method for multiplication of repetition frequency in optical pulse trains. The device and the method multiply repetition frequency of optical pulse train generated with ML-FRL with high stability. The device comprises an optical fibre ring composed of optical fibres, an optical amplifier and a modulator for optically modulating, and an electric signal generator generating high frequency signals. The device generates an optical pulse train of repeating frequency of fm, when applying electric signals of frequency of fm to the modulator. In addition to the construction, the stabilised optical pulse generator comprises a filter passing through frequencies of integer multiple of the applied modulation frequency fm, and a composite cavity composed of a plurality of optical fibres of which lengths are different each other.
    Type: Application
    Filed: March 11, 2003
    Publication date: September 18, 2003
    Applicant: Communications Research Laboratory, Independent Administrative Institution
    Inventor: Kamal Kant Gupta
  • Patent number: 6538793
    Abstract: The present invention discloses an electronically frequency tunable and phase modulatable quasi-optic grid oscillator. The oscillator includes a reference signal input port whereby a small external reference signal is introduced that entrains the frequency and phase of the oscillator signal to it. Amplitude modulation techniques are introduced to further enhance the utility of the oscillator as a modulator.
    Type: Grant
    Filed: June 5, 2001
    Date of Patent: March 25, 2003
    Assignee: California Institute of Technology
    Inventors: James J. Rosenberg, Blythe C. Deckman, David B. Rutledge
  • Patent number: 6532099
    Abstract: A large, high-speed optical communications apparatus is provided capable of selecting a signal transmission route in optical domain. An address extractor 101 extracts address information from data information included in a transmission signal. A variable frequency RF modulator 102 modulates the data information into an RF modulated signal having a predetermined frequency that corresponds to a lower address. A variable wavelength optical modulator 103 modulates the RF modulated signal into an optical signal having a predetermined wavelength that corresponds to an upper address. An optical router 105 outputs the optical signal according to the optical wavelength. A first RF optical router 1071 outputs the optical signal from a first or second output terminal provided thereto according to the RF modulating frequency. A second RF optical router 1072 operates similarly.
    Type: Grant
    Filed: July 6, 2001
    Date of Patent: March 11, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Masaru Fuse
  • Patent number: 6525862
    Abstract: Methods and apparatus directed to using modulation to substantially improve detection limits in optical imaging, and to substantially improve the performance of various optical imaging systems. In an illustrative embodiment, such modulation is achieved using a modulated light source, a modulation frequency reference, a detector, and a demodulator. The modulated light source may comprise a light source emitting an inherently modulated output; alternately, this modulated light source may comprise a separate optical modulator and a continuous wave, modulated, or pulsed light source configured so as to impose a modulation in the output of light source. Methods for imaging using such modulation are also disclosed.
    Type: Grant
    Filed: February 8, 2001
    Date of Patent: February 25, 2003
    Assignee: Photogen, Inc.
    Inventors: Walter G. Fisher, Eric A. Wachter