Amplitude Modulation Patents (Class 359/286)
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Patent number: 9976990Abstract: A vibration measuring apparatus comprises a wave transmission section configured to vibrate a measurement object with sound wave output from a parametric speaker towards the measurement object and an optical measurement section configured to emit laser light towards the measurement object, receive the laser light reflected from the measurement object and measure vibration of the assumed object (measurement object) according to the received laser light. The wave transmission section and the optical measurement section are mounted integrally, and the optical measurement section makes an optical axis of laser light emitted to/received from the measurement object coincident with a central axis of the sound wave output from the parametric speaker.Type: GrantFiled: December 28, 2015Date of Patent: May 22, 2018Assignee: TOSHIBA TEC KABUSHIKI KAISHAInventors: Daisuke Ishikawa, Kenichi Komiya
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Patent number: 9954342Abstract: The laser assembly includes a semiconductor with an active semiconductor region, a controllable oscillator for generating a periodic electric signal that is applied to the semiconductor laser to generate a surface acoustic wave in or near the active semiconductor region such that a diffraction grating structure is created in or near the active semiconductor region by the surface acoustic wave, an emission wavelength of the active semiconductor region being determined by a periodicity of the diffraction grating structure, wherein the controllable oscillator is configured to set a frequency of the periodic electric signal in accordance with a control signal, and a control circuit for generating the control signal for the controllable oscillator in such a manner that a shift of the emission wavelength from heating of the active semiconductor region during emission of the optical signal is at least partially compensated by an opposite shift of the emission wavelength from a change of the periodicity of the diffraType: GrantFiled: December 14, 2015Date of Patent: April 24, 2018Assignee: Alcatel LucentInventor: Thomas Pfeiffer
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Patent number: 9887459Abstract: A reconfigurable aperture includes a plurality of metallic particles confined to a volume extending across an aperture area. The metallic particles are repositioned within the volume to form opaque regions in the aperture area. The opaque regions, and transmissive regions between the opaque regions, can form a reconfigurable zone plate that can change the collimation of a microwave beam via diffraction therethrough. The zone plate can be located a fixed distance away from a microwave source and a detector in a housing, so that for any specified wavelength produced by the microwave source, the zone plate can reconfigure to have a focal length equal to the fixed distance. The reconfigurable zone plate can effectively collimate microwaves produced by the microwave source, can direct the collimated microwaves in a specified direction, can receive microwaves returning along the specified direction, and can focus the received microwaves onto the detector.Type: GrantFiled: September 27, 2013Date of Patent: February 6, 2018Assignee: Raytheon BBN Technologies Corp.Inventors: Mark D. Casciato, Matthew John Rebholz, Justin Wales Swartz
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Patent number: 9268075Abstract: Provided is a method of manufacturing a wire gird polarizer. The method includes sequentially stacking a conductive wire layer and a first neutral layer, forming guide patterns, reducing widths of the guide patterns and patterning the first neutral layer, forming a second neutral layer, applying a first block copolymer, arranging the first block copolymer as a first monomer block and a second monomer block, removing one of the first monomer block and the second monomer block, removing the second neutral layer exposed, removing the remaining monomer block and the guide patterns, applying a second block copolymer, arranging the second block copolymer as a third monomer block and a fourth monomer block, removing one of the third monomer block and the fourth monomer block, and patterning the conductive wire layer to thereby form conductive wire patterns.Type: GrantFiled: April 3, 2015Date of Patent: February 23, 2016Assignee: SAMSUNG DISPLAY CO., LTD.Inventors: Dae Ho Yoon, Seung Won Park, Moon Gyu Lee, Tae Woo Kim, Lei Xie
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Patent number: 8908725Abstract: The invention relates to an external cavity tunable laser. The laser comprises an extracavity collimating lens arranged outside a laser cavity, and a laser output mirror, a laser gain medium, an intracavity collimating lens, an active optical phase modulator and a tunable optical filter all arranged sequentially inside the laser cavity. The laser further comprises an active polarization rotator arranged behind the tunable optical filter, a polarization beam splitter arranged behind the active polarization rotator, a first etalon and a first total reflection mirror arranged in the direction vertical to the optic axis of a laser cavity output lens, a second etalon and a second total reflection mirror arranged in the direction of the optic axis of the laser cavity output lens, and a laser drive and control circuit.Type: GrantFiled: August 23, 2013Date of Patent: December 9, 2014Inventor: Peiliang Gao
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Patent number: 8831050Abstract: A tunable laser, including: a laser resonant cavity; a laser gain medium; an intra-cavity collimating lens; an acousto-optic tunable filter; a device exciting sound waves in an acousto-optic crystal; a radio frequency signal source providing radio frequency energy for the energy transducer and adjusting the oscillation wavelength of the laser resonant cavity by changing radio signal frequency; an optical phase modulator disposed between the intra-cavity collimating lens and the acousto-optic crystal; an optical etalon disposed between the optical phase modulator and the laser gain medium; a wavelength locker disposed at one of zero-order diffraction optical paths of intra-cavity light; a pigtailed collimator coupling laser output light to an optical fiber; a pumping source exciting the laser gain medium; a phase modulator driver for driving the optical phase modulator; and a signal control processing circuit.Type: GrantFiled: September 28, 2012Date of Patent: September 9, 2014Assignee: GP Photonics, Inc.Inventor: Peiliang Gao
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Publication number: 20140240812Abstract: Provided is an acousto-optic device including an elastic medium; a meta structure formed on a first surface of the elastic medium, and an elastic-wave generating unit which generates an elastic wave in the elastic medium. The meta structure includes a first layer and a second layer that is formed on the first layer. The at least one of the first layer and the second layer includes a predetermined repetitive pattern.Type: ApplicationFiled: January 23, 2014Publication date: August 28, 2014Applicants: AJOU UNIVERSITY INDUSTRY COOPERATION FOUNDATION, SAMSUNG ELECTRONICS CO., LTD.Inventors: Seung-hoon HAN, Wan-joo MAENG, Won-taek SEO, Hoon SONG, Hae-kwan OH, Kee-keun LEE
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Patent number: 8724209Abstract: An acousto-optic (AO) device includes an AO interaction crystal for receiving and propagating a light ray along an optical propagation direction (OPD). A piezoelectric transducer is on at least one surface of the AO interaction crystal for receiving an electrical signal and emitting an acoustic wave into the AO interaction crystal. An electrode is on the piezoelectric transducer for coupling the electrical signal to the piezoelectric transducer. The electrode is a patterned electrode that includes a plurality of different transverse edge positions. The plurality of different transverse edge positions span a position range of at least five percent of an average height (Havg) of the electrode.Type: GrantFiled: December 14, 2011Date of Patent: May 13, 2014Assignee: Gooch and Housego PLCInventor: Christopher N. Pannell
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Publication number: 20140035959Abstract: The present invention provides a light field display device (300) comprising an array of light field display elements (310) populating a display surface, each display element (310) comprising: a beam generator (522) for generating an output beam of light; a radiance modulator (524) for modulating the radiance of the beam over time; a focus modulator (530) for modulating the focus of the beam over time; and a scanner (504, 506) for scanning the beam across a two-dimensional angular field.Type: ApplicationFiled: August 4, 2012Publication date: February 6, 2014Inventor: Paul Lapstun
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Patent number: 8576206Abstract: The present invention relates to a phase modulating apparatus capable of highly accurately and easily correcting the phase modulation characteristic of a reflective electric address spatial light modulator even when a condition of input light is changed. In the LCOS phase modulating apparatus, an input unit inputs the condition of the input light, and a processing unit sets an input value for each pixel. A correction value deriving unit determines a correction condition according to the condition of the input light. A control input value converting unit converts the input value set for each pixel into a corrected input value based on the correction condition. An LUT processing unit converts the corrected input value into a voltage value, and drives each pixel by using a drive voltage equivalent to the converted voltage value.Type: GrantFiled: December 4, 2008Date of Patent: November 5, 2013Assignee: Hamamatsu Photonics K.K.Inventors: Naoya Matsumoto, Norihiro Fukuchi, Takashi Inoue, Yasunori Igasaki
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Patent number: 8537476Abstract: A support system for a vibrating component of an optical assembly that is adjacent to a frame, wherein the component is driven to vibrate along an X-direction of a three-dimensional Cartesian coordinate system. The support system includes a support member connected to the frame. The support system has contact elements that are adjustable for movement into and out of contact with the vibrating component to constrain motion of the vibrating component in the Y-direction and in the Z-direction, without constraining motion of the vibrating component in the X-direction.Type: GrantFiled: June 6, 2008Date of Patent: September 17, 2013Assignee: Hinds Instruments Inc.Inventors: James C. Mansfield, Baoliang Wang
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Patent number: 8361593Abstract: A plasmonic coating for reflecting electromagnetic energy is disclosed. The coating includes a plurality of layers, at least one of which is a dielectric layer; and a patterned dielectric layer in structural communication with the plurality of layers and having a pattern configured to plasmonically reflect electromagnetic energy incident thereon.Type: GrantFiled: October 17, 2007Date of Patent: January 29, 2013Assignee: Lockheed Martin CorporationInventor: Clara A. Rivero
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Patent number: 7860135Abstract: An acousto-optic deflector includes a body of material through which a laser beam to be modulated passes. The material has an acoustic attenuation in the range of 0.15 to 1.0 dB/?s-GHz2 and operates in a UV range of about 150 to 400 nm. A transducer is bonded to the body of material to launch a wave. An electronic driver drives the transducer.Type: GrantFiled: February 24, 2009Date of Patent: December 28, 2010Assignee: Crystal Technologies, Inc.Inventor: Ronald C. Dwelle
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Patent number: 7768687Abstract: A photoelastic modulator, comprising a driving block and a driver transducer for perturbing said block in a predefined direction to establish a standing wave extending longitudinally in said block and hence perpendicularly to said predefined direction. The transducer is affixed to said block at two regions of the transducer mutually displaced in said predefined direction, to minimize the coupling of lateral perturbation perpendicular to the predefined direction. A recess or gap may be provided under the transducer.Type: GrantFiled: January 30, 2007Date of Patent: August 3, 2010Assignee: Endeavour Instruments Pty. LtdInventor: William Pui Ling
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Patent number: 7697195Abstract: We disclose acousto-optic modulators that include: (a) an optical element configured to receive an input optical beam that propagates along a first direction; and (b) a transducer extending along the first direction and positioned on one or more surfaces of the optical element, the transducer having a transducer material positioned between two electrodes configured to apply a potential difference across the transducer to cause the transducer to generate an acoustic waveform propagating in a second direction in the optical element, and the input optical beam undergoing diffraction in a region of the optical element that includes the acoustic waveform.Type: GrantFiled: May 25, 2007Date of Patent: April 13, 2010Assignee: Zygo CorporationInventor: Henry A. Hill
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Publication number: 20100040096Abstract: The present invention relates to a spectral stretching and control device for high peak power pulse lasers, which does not limit the extraction efficiency of the amplifiers in the CPA chain into which said device can be inserted, and it is characterized in that it comprises an acousto-optical device for dispersing light pulses, which is programmable in terms of spectral amplitude, disposed in a multi-pass amplifier.Type: ApplicationFiled: July 11, 2007Publication date: February 18, 2010Applicant: ThalesInventor: Franck Falcoz
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Patent number: 7639910Abstract: 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: GrantFiled: June 6, 2007Date of Patent: December 29, 2009Assignee: NEC CorporationInventors: Hiroyuki Yamazaki, Takaaki Hatanaka
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Publication number: 20090268272Abstract: The present invention relates to optical communication, and discloses an optical modulation system and an optical modulation method. The system includes: a light emitting apparatus, a wavelength sensor, a signal processor, a controller, a pulse modulation driver, an amplitude modulation driver, and an amplitude modulator. The method includes: receiving a second optical signal among optical signals generated by a light emitting apparatus, and outputting intermittent optical signals of stable wavelengths under modulation of an amplitude drive signal, where: the optical signals are generated by the light emitting apparatus under control of a wavelength control signal and have stable wavelengths, and the wavelength control signal is generated by calculating a first optical signal emitted by the light emitting apparatus.Type: ApplicationFiled: July 2, 2009Publication date: October 29, 2009Applicant: Huawei Technologies Co., Ltd.Inventor: Guozhong Wang
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Patent number: 7446857Abstract: An acousto-optic cell is used in a method and device for patterning a workpiece, for exposing a radiation sensitive layer on a workpiece such as a mask or a device substrate. The acousto-optic cell includes an array of transducers. The transducers may supply columns of ultrasound to the cell. They may produce a two dimensional modulation pattern within the cell. Electromagnetic radiation is modulated by the cell and related to a workpiece. The modulation of the cell may modulate the amplitude and/or phase of the electromagnetic radiation. In some embodiments, adjoining columns of ultrasound may be positioned so that portions of the electromagnetic radiation partially overlap and interfere, after they are modulated.Type: GrantFiled: May 7, 2007Date of Patent: November 4, 2008Assignee: Micronic Laser Systems ABInventor: Torbjorn Sandstrom
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Publication number: 20080247027Abstract: An acousto-optic modulator includes an acousto-optic bulk medium and transducer attached to the acousto-optic bulk medium and formed as a linear array of electrodes. A transducer driver is connected to each electrode and is coherently phase driven to alter the angular momentum distribution of an acoustic field and alternately allow and inhibit phase matching between the optical and acoustic field and produce a desired intensity modulation of an optical wavefront.Type: ApplicationFiled: April 6, 2007Publication date: October 9, 2008Applicant: HARRIS CORPORATIONInventor: Peter A. Wasilousky
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Patent number: 7405414Abstract: The present invention relates to a method for creating a pattern on a workpiece sensitive to electromagnetic radiation. Electromagnetic radiation is emitted onto a computer controlled reticle having a multitude of modulating elements (pixels). The pixels are arranged in said computer controlled reticle according to a digital description. An image of said computer controlled reticle is created on said workpiece, wherein said pixels in said computer controlled reticle are arranged in alternate states along at least a part of one feature edge in order to create a smaller address grid. The invention also relates to an apparatus for creating a pattern on a workpiece. The invention also relates to a semiconducting wafer and a mask.Type: GrantFiled: December 11, 2002Date of Patent: July 29, 2008Assignee: Micronic Laser Systems ABInventor: Torbjorn Sandstrom
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Patent number: 7397018Abstract: An adaptive optics system is provided. The system includes a light source, a pair of deformable mirrors and a detection module. The light source is configured to provide an outgoing beam. The outgoing beam has an amplitude and a phase. The first deformable mirror is configured to reflect the outgoing beam and adjust its associated amplitude. The second deformable mirror is configured to reflect the outgoing beam reflected from the first deformable mirror and adjust its associated phase. The detection module is configured to detect an incoming beam and the reflected outgoing beam from the second deformable mirror and generate certain signals. The signals are used to control the first and second deformable mirrors such that the amplitude of the outgoing beam is the same as that of the incoming beam and the phase of the outgoing beam is opposite that of the incoming beam.Type: GrantFiled: March 2, 2005Date of Patent: July 8, 2008Assignee: Lockheed Martin CorporationInventors: Ich V. Pham, Gopal Vasudevan
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Patent number: 7385749Abstract: An acousto-optic modulator includes a (100), (010) or (001) single crystal silicon acousto-optic interaction medium, and at least one transducer for emitting an acoustic wave attached to the single crystal. The transducer has a first electrode layer disposed on one side and a second electrode layer disposed on its other side. The transducer is aligned to the single crystal so that the direction of acoustic propagation in the silicon crystal is substantially along the (100), (010) or (001) direction. A q-switched laser includes a modulator according to the invention.Type: GrantFiled: September 26, 2006Date of Patent: June 10, 2008Assignee: Cleveland Crystals, Inc.Inventors: Christopher N. Pannell, Thomas Stenger, Jonathan David Ward, Melvin E. Pedinoff, Ramesh K. Shori
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Publication number: 20080037101Abstract: The invention relates a wire grid polarizer that includes a micropatterned substrate having channels. An electrically conductive material is disposed on the micropatterned substrate in strips having a width of 10 to 20 nm and oriented either parallel or perpendicular to the channels.Type: ApplicationFiled: August 11, 2006Publication date: February 14, 2008Inventors: Ramesh Jagannathan, YuanQiao Rao, Xiang-Dong Mi
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Patent number: 7283290Abstract: An acousto-optic (AO) device for generating a highly apodized acoustic wave field includes a piezoelectric transducer crystal for emitting an acoustic wave having a ground electrode disposed on one side of the piezoelectric crystal, and a patterned electrode layer disposed on a side of the piezoelectric crystal opposite the ground electrode. The patterned electrode layer includes a continuous region proximate to its center and a discontinuous region, a pattern in the discontinuous region including a plurality of spaced apart features electrically connected to the continuous region. An AO interaction crystal which receives the acoustic wave is attached to the ground electrode or the patterned electrode layer.Type: GrantFiled: March 29, 2006Date of Patent: October 16, 2007Assignee: Gooch and Housego PLCInventors: Christopher N. Pannell, Elliot S. Wachman
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Patent number: 7006715Abstract: A first optical waveguide, a second optical waveguide, a first electrode, and a second electrode are integrated on a substrate. An optical modulator is provided with a clock signal generator for generating an RZ signal by applying a clock signal to either the first or second electrode, and an NRZ data signal generator for supplying an NRZ data signal to the remaining electrode. Thus, the space required by the optical modulator is reduced while tolerance of the same is improved, thus reducing costs for constructing the optical modulator.Type: GrantFiled: May 14, 2003Date of Patent: February 28, 2006Assignee: Fujitsu LimitedInventors: Masaharu Doi, Tetsuo Ishizaka, Takehito Tanaka
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Patent number: 6990260Abstract: An extended optical sensor comprises a plurality of equally spaced intensity-based point sensors connected in parallel such that the optical path lengths are the same within the extended sensor enclosure. The input to the extended sensor is a single optical fiber as is the output.Type: GrantFiled: June 9, 2004Date of Patent: January 24, 2006Assignee: Lockheed Martin CorporationInventor: Byron W. Tietjen
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Patent number: 6906844Abstract: An improved system for mounting an optical assembly of a photoelastic modulator (PEM) to permit free vibration of the optical assembly without introducing any stress or strain on the optical element. Moreover, the mounting system, which includes a mounting block (50), elastomeric mount (32), support flanges (36, 38), and a mounting rail (40), facilitates accurate and easy assembly of the optical element into its enclosure (26).Type: GrantFiled: July 25, 2000Date of Patent: June 14, 2005Assignee: Hinds Instruments, IncInventor: Massoud Siahpoushan
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Patent number: 6775051Abstract: Systems and methods for scanning a beam of light over a specimen are provided. A system may include a pre-scan acousto-optical deflector (AOD) configured to deflect a beam of light, a second AOD configured as a traveling lens to focus the scanning beam, a relay lens, and an objective lens. The relay lens may be centered on the scan line produced by the second AOD, while the objective lens may be substantially de-centered with respect to the relay lens to produce a telecentric scanning spot with no field tilt. The system may modulate the amplitude of the sound wave in the first AOD to compensate for attenuation in the second AOD. The system may pre-fill one chirp packet in the second AOD while another chirp packet is scanning to substantially reduce a delay between consecutive scans.Type: GrantFiled: May 3, 2002Date of Patent: August 10, 2004Assignee: KLA-Tencor TechnologiesInventors: Jamie Sullivan, Ralph Johnson, John Gibson, Mingguang Li, Eric Vella
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Patent number: 6771412Abstract: The present invention relates to acousto-optic applications of parametric optical apparatuses that use the mechanical energy of elastic oscillations to convert light over a wide range of wavelengths and amplitudes and to generate coherent light.Type: GrantFiled: July 20, 2001Date of Patent: August 3, 2004Inventor: Vladimir P. Torchigin
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Patent number: 6741381Abstract: Acousto-optical filter systems for filtering a light beam by generating undiffracted and diffracted light beams within a birefringent crystal and by suppressing the diffracted beam within or at a face of the crystal. Where the two beams are noncollinear, an aperture provides diffracted beam suppression. Where the two beams have different polarization directions, the diffracted beam is suppressed by a polarization analyzer, internal reflection of each beam at a Brewster angle at the surface, total internal reflection of the diffracted beam at the surface, or a suitably oriented multilayer thin film at the surface. Variation of the acoustic frequency provides tunability of the filter.Type: GrantFiled: November 8, 2002Date of Patent: May 25, 2004Assignee: Picarro, Inc.Inventors: Marc Levenson, Robert Lodenkemper
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Publication number: 20040012837Abstract: The invention concerns a device comprising a birefringent elasto-optic medium (1) equipped with a transducer (5) generating in the medium (1) a modulated acoustic wave along a specific direction, and means for coupling in the medium (1) an input optical wave with unknown polarisation, and a programming circuit for (amplitude-phase-frequency) modulation of the acoustic wave. Said device supplies a direct wave and two perpendicular diffracted waves of H, V polarisation each bearing a modulation based on the input optical wave modulation and the acoustic wave modulation.Type: ApplicationFiled: July 3, 2003Publication date: January 22, 2004Inventors: Daniel Kaplan, Thomas Oksenhendler, Pierre Tournois
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Patent number: 6618183Abstract: The method and apparatus for amplitude modulation of unpolarized light by at least one Bragg modulator on the basis of domain-invertible material, the unpolarized light is modulated by a first Bragg modulator both for defining a polarization plane in the unpolarized light and for modulating a light part to be allocated to the polarization plane. A second Bragg modulator is provided which modulates the light part of the unpolarized light allocated to the polarization plane orthogonal to the polarization plane of the first Bragg modulator. The method and apparatus are particularly useful for recording a product to be printed, such as for manufacturing printing forms.Type: GrantFiled: October 30, 2001Date of Patent: September 9, 2003Assignee: Heidelberger Druckmaschinen AktiengesellschaftInventors: Joerg-Achim Fischer, Axel Gebhardt, Peter Ressel
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Publication number: 20030016434Abstract: The present invention relates to acousto-optic applications of parametric optical apparatuses that use the mechanical energy of elastic oscillations to convert light over a wide range of wavelengths and amplitudes and to generate coherent light.Type: ApplicationFiled: July 20, 2001Publication date: January 23, 2003Inventor: Vlandimir P. Torchigin
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Publication number: 20020063942Abstract: The method and apparatus for amplitude modulation of unpolarized light by at least one Bragg modulator on the basis of domain-invertible material, the unpolarized light is modulated by a first Bragg modulator both for defining a polarization plane in the unpolarized light and for modulating a light part to be allocated to the polarization plane. A second Bragg modulator is provided which modulates the light part of the unpolarized light allocated to the polarization plane orthogonal to the polarization plane of the first Bragg modulator. The method and apparatus are particularly useful for recording a product to be printed, such as for manufacturing printing forms.Type: ApplicationFiled: October 30, 2001Publication date: May 30, 2002Applicant: Heidelberger Druckmaschinen AGInventors: Joerg-Achim Fischer, Axel Gebhardt, Peter Ressel
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Patent number: 6392821Abstract: A projector for producing a visually perceptible light image along predetermined vector coordinates, includes a light source for producing a beam of light along a light path; a deflector positioned to deflect the beam of light along the vector coordinates; a focusing lens for focusing the deflected light beam; and a projection reflector for reflecting the beam along the vector coordinates to thereby form the visually perceptible light image. A preferred light source comprises a laser, and a preferred reflecting surface has a substantially convex shape, preferably including a parabolic reflector.Type: GrantFiled: September 28, 2000Date of Patent: May 21, 2002Inventor: William R. Benner, Jr.
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Publication number: 20020054421Abstract: An optical modulation scheme for transmitting data over a fiber optic transmission line is proposed where the following steps are realized:Type: ApplicationFiled: November 5, 2001Publication date: May 9, 2002Applicant: ALCATELInventor: Hans Bissessur
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Patent number: 6307665Abstract: An acousto-optic modulator including an ultrasonic medium for controlling light from an optical source through diffraction, two transducers each having one electrode formed on one side thereof, the electrodes being for generating an acousto-elastic wave, and a conductive adhesive layer interposed between the ultrasonic medium and each of the sides of the transducers opposite to the sides on which the electrodes are installed, in order to adhere each of the transducers to the ultrasonic medium.Type: GrantFiled: March 22, 1999Date of Patent: October 23, 2001Assignee: Samsung Electronics Co., Ltd.Inventors: Yong-hoon Kim, Hang-woo Lee
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Patent number: 6016216Abstract: A polarization independent acousto-optic tunable filter (PIAOTF) used for multiwavelength switching and routing in wavelength division multiplexing (WDM) networks. In the PIAOTF an incident unpolarized light beam is divided to propagate and to be diffracted along two polarization division branches. By using polarization converters and equal optical paths for the two polarization division channels, a PIAOTF is created which minimizes polarization dependent loss and polarization mode dispersion. Furthermore, a preferred embodiment of the AOTF using an elongated acousto-optic interaction medium is described that provides the additional advantages of narrow bandwidth, lower drive power and easier alignment.Type: GrantFiled: May 17, 1997Date of Patent: January 18, 2000Assignee: Aurora Photonics, Inc.Inventor: I-Cheng Chang
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Patent number: 5886810Abstract: An optical assembly comprising an optical element and a transducer is suspended within an enclosure so that the optical assembly is free to vibrate within the enclosure. In one embodiment, the mechanisms for suspending the assembly do away with any elastomeric material that would cause outgassing in applications where the photoelastic modulator is used in a high vacuum environment. The suspension system also increases the efficiency of the system.Type: GrantFiled: September 29, 1997Date of Patent: March 23, 1999Assignee: Hinds Instruments, Inc.Inventors: Massoud M. Siahpoushan, James A. Hinds, Richard R. Rockwell
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Patent number: 5838484Abstract: A micromechanical optical modulator having a linear response in reflectivity, as a function of applied bias, and a method of operating and making same, are disclosed. The modulator consists of a movable layer suspended over a substrate. A gap is defined between the movable layer and the substrate. As the movable layer moves, the gap changes size, resulting in a change in modulator reflectivity. In operation, the movable layer moves within a linear operating regime under the action of an applied voltage, which is the sum of a constant bias and a signal from an analog source. A substantially linear operating characteristic, i.e., reflectivity versus applied voltage is obtained within the linear operating regime by properly selecting the size of the gap in the absence of the applied voltage and the range in the applied voltage.Type: GrantFiled: August 19, 1996Date of Patent: November 17, 1998Assignee: Lucent Technologies Inc.Inventor: Keith Wayne Goossen
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Patent number: 5781327Abstract: An electro-optic modulator and a method for its use, in which an optical carrier is effectively suppressed for transmission of a radio-frequency (rf) modulating signal over an optical communication link, to provide improved demodulator performance. A carrier component is recovered from the modulator, amplified, and reused, to minimize the effect of optical carrier losses. In one embodiment of the invention, a modulator (10) with complementary output ports (20 and 22) generates a carrier-suppressed output (FIG. 2B) containing rf sidebands from one port (20) and a strong carrier component (FIG. 2C) from the other output port (22). The carrier component is filtered in a residual sideband filter (14), amplified in an optical amplifying medium (12) and returned to the modulator (10) as its carrier input. In a second embodiment of the invention, a modulator (30) with a single output port produces rf sidebands and a suppressed carrier component (FIG.Type: GrantFiled: August 19, 1996Date of Patent: July 14, 1998Assignee: TRW Inc.Inventors: John C. Brock, Michael G. Wickham
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Patent number: 5633747Abstract: An apparatus for both deflecting a beam of light illuminating a spot on a surface and varying the size of the spot, electronically, without changing any system components. The apparatus includes an acousto-optic deflector driven with a linear FM signal produced by a chirp signal generator. The linear FM signal is characterized with a dispersion rate, and the chirp signal generator includes a chirp dispersion selector to vary the dispersion rate. A beam of collimated light passes through the acousto-optic deflector and appropriate focusing optics image the beam onto a spot in a nominal focal plane. The chirp dispersion selector sets the dispersion rate in accord to a nominal rate, resulting in the beam illuminating a spot in the focal plane. Generally, the focal plane coincides with a wafer surface, of the type having periodic and non-periodic features on it. The spot size may be varied from that of a diffraction limited spot to a spot whose maximum size is system dependent.Type: GrantFiled: December 21, 1994Date of Patent: May 27, 1997Assignee: Tencor InstrumentsInventor: Mehrdad Nikoonahad
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Patent number: 5412501Abstract: The present invention is a scanning system and a novel method for compensating for the variations in the output power of the beam from an A-O cell. The novel method involves varying the amount of drive current through the laser diode in such a fashion as to compensate for the loss of power due to diffraction inefficiencies. The amount of driving current is dependent upon the amount of power desired in the output beam from the A-O cell. The system and method of the present invention sets the output power from the A-O cell to a desired value. As the diffraction efficiency increases at other portions of the scan, the drive current is cut appropriately to compensate for the increased efficiency; thus keeping the output spot power at the desired value. Likewise, as the diffraction efficiency decreases at other portions of the scan, the drive current should be increased to compensate for the decrease in efficiency; thereby maintaining the desired value.Type: GrantFiled: November 17, 1993Date of Patent: May 2, 1995Assignee: Xerox CorporationInventor: Tibor Fisli
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Patent number: 5357097Abstract: An apparatus for controlling an acousto-optic filter includes a high-frequency oscillator, a beam intensity detector, a first and a second oscillator, and a first and a second controller. The high-frequency oscillator drives the acousto-optic filter and the frequency of the driving signal is finely modulated by oscillation frequency f.sub.0 of the first oscillator. The detector detects an output signal beam intensity of the acousto-optic filter. An output of the detector is synchronously detected at the frequency f.sub.0 and the frequency of the driving signal is controlled by the first controller so that the resultant detected output becomes zero. Similarly, the amplitude of the driving signal is finely modulated by the oscillation frequency f.sub.1 of the second oscillator. The output of the detector is synchronously detected at the frequency f.sub.1 and the amplitude of the driving signal is controlled by the second controller so that the resultant detected output becomes zero. The frequency f.sub.Type: GrantFiled: November 25, 1992Date of Patent: October 18, 1994Assignee: Nec CorporationInventors: Takahiro Shiozawa, Naoki Shimosaka
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Patent number: 5309178Abstract: A laser marking apparatus includes at least one laser beam source, a multichannel acoustic modulator defining a plurality of at least partially overlapping modulation regions, apparatus for directing at least one laser beam from the at least one laser beam source through the multichannel acoustic modulator such that each laser beam extends across at least two of the at least partially overlapping modulation regions, and imaging apparatus for directing light from the modulator to a laser marking image plane.Type: GrantFiled: May 12, 1992Date of Patent: May 3, 1994Assignee: Optrotech Ltd.Inventor: Abraham Gross
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Patent number: 5251057Abstract: In a raster output scanner, a system for using one original beam and one facet of a rotating polygon to generate two consecutive scan lines. The original beam is first separated into two beams in a beam splitter. The resultant beams are polarized ninety degrees apart, and directed to the modulator. The beams are a sufficient distance apart so that the A/O modulator can modulate each beam with a minimum of crosstalk. The output beams are then brought together to within one scan line separation by a beam recombiner, which is a reversed beam splitter. The beams can be brought together to this close proximity without optical interference because the beams are plarized ninety degrees apart.Type: GrantFiled: October 13, 1989Date of Patent: October 5, 1993Assignee: Xerox CorporationInventors: Jean-Michel Guerin, Melvin E. Swanberg
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Patent number: 5251058Abstract: In a raster output scanner, a system for using one original beam and one facet of a rotating polygon to generate a scan line which can be turned on to have three levels of intensity. The original beam is first separated into two beams in a beam splitter. The resultant beams are polarized ninety degrees apart, and directed to the modulator. The beams are a sufficient distance apart so that the A/O modulator can modulate each beam with a minimum of crosstalk. The output beams are then brought together and combined into one beam without optical interference because the beams are polarized ninety degrees apart. The beam can have several levels of intensity and be used to create several levels of gray scale at the output.Type: GrantFiled: October 13, 1989Date of Patent: October 5, 1993Assignee: Xerox CorporationInventor: Thomas D. MacArthur
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Patent number: 5249196Abstract: An internally folded scalable laser has a gain medium with an internal face nd an external face and at least one internal-fold face subtending an angle which may be about 90.degree.. An output coupler that is partially reflective of the resonator mode is oriented to receive and reflect resonator mode in a direction normal to the internal face to avoid resonator mode astigmatism and to define a folded hemispherically-shaped resonator cavity extending from the output coupler and through an active volume in the gain medium to the external face. A pumping mode source disposed adjacent to the external face is oriented to focus a first pumping mode in a direction normal to the external face in a boom waist at or inside the external face in the folded resonator cavity to define an active volume in the gain medium and to avoid pumping mode astigmatism.Type: GrantFiled: May 21, 1992Date of Patent: September 28, 1993Assignee: The United States of America as represented by the Secretary of the NavyInventor: Richard Scheps
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Patent number: 5153771Abstract: A acousto-optic Fabry-Perot optical modulator (10) has a crystalline body (12) having a first partially reflective electrode (14) for receiving radiation, including laser radiation having a wavelength or wavelengths of interest, and a second, oppositely disposed partially reflective electrode (14) for emitting the received radiation including the laser radiation. The modulator is driven by an alternating source (16) at a resonant frequency of the crystalline body and intensity modulates at the resonant frequency only the emitted laser radiation. A detector (18) is positioned for receiving the emitted radiation, including the intensity modulated laser radiation, and has an output signal expressive of the intensity of the emitted radiation. Signal processing circuitry (20,34) is coupled to the detector output signal and is responsive thereto for identifying the intensity modulated laser radiation for indicating when laser radiation is received by the modulator.Type: GrantFiled: July 18, 1990Date of Patent: October 6, 1992Assignee: Northrop CorporationInventors: Charles A. Link, Paul D. Lang