Feedback Circuitry Patents (Class 372/29.011)
  • Patent number: 8204091
    Abstract: Particular embodiments of the present invention relate generally to semiconductor lasers and laser projections systems and, more particularly, to schemes for controlling semiconductor lasers. According to one embodiment of the present invention, a laser having a gain section, a phase section and a wavelength selective section is configured for optical emission of encoded data. The optical emission is shifted across a plurality of laser cavity modes by applying a quasi-periodic phase shifting signal I/V? to the phase section of the semiconductor laser. The amplitude of the quasi-periodic signal transitions periodically between a maximum drive level and a minimum drive level at a frequency that varies randomly over time.
    Type: Grant
    Filed: July 3, 2008
    Date of Patent: June 19, 2012
    Assignee: Corning Incorporated
    Inventors: Martin Hai Hu, Dragan Pikula, Daniel Ohen Ricketts
  • Patent number: 8189630
    Abstract: A highly portable, high-powered infrared laser source is produced by intermittent operation of a quantum cascade laser power regulated to a predetermined operating range that permits passive cooling. The regulation process may boost battery voltage allowing the use of a more compact, low-voltage batteries.
    Type: Grant
    Filed: May 18, 2010
    Date of Patent: May 29, 2012
    Assignee: Daylight Solutions, Inc.
    Inventors: Rob Marsland, Jr., Timothy Day
  • Patent number: 8183509
    Abstract: The present invention relates to a laser processing apparatus and the like having a structure for implementing at the same time both an efficient laser processing in the place where a laser beam is difficult to reach and a laser processing without damages in the place where the laser beam is easy to reach. This laser processing apparatus comprises a laser light source, an irradiation optical system applying a laser beam to an object while scanning the laser beam, a photo-detector detecting the laser beam applied from the irradiation optical system, and a control section of making switching between a continuous oscillation and a pulse oscillation of the laser beam at the laser light source.
    Type: Grant
    Filed: July 28, 2011
    Date of Patent: May 22, 2012
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Motoki Kakui, Kazuo Nakamae, Shinobu Tamaoki
  • Patent number: 8178826
    Abstract: A light source device including a semiconductor light emitting element and a control section for controlling the semiconductor light emitting element in accordance with an input value. The control section includes a supply section that supplies the semiconductor light emitting element with a drive current based on the input value and an estimated threshold current of the semiconductor light emitting element, and an estimation section that obtains the estimation of the threshold current using the drive current and the amount of light detected to be emitted from the semiconductor light emitting element.
    Type: Grant
    Filed: October 9, 2008
    Date of Patent: May 15, 2012
    Assignee: Seiko Epson Corporation
    Inventor: Tomio Ikegami
  • Patent number: 8170074
    Abstract: A method of estimating an injection power of seed light injected into an injection-seeded transmitter. A back face monitoring (BFM) response of the injection-seeded transmitter is determined, and data representative of the BFM response stored in a memory. During run-time, a controller of the injection-seeded transmitter, detects a temperature of the injection-seeded transmitter and an instantaneous BFM current. BFM response data is obtained from the memory based on the detected temperature, and the seed light injection power estimated based on the obtained data and the detected instantaneous BFM current.
    Type: Grant
    Filed: April 8, 2011
    Date of Patent: May 1, 2012
    Assignee: Nortel Networks Limited
    Inventors: Bin Cao, Douglas James Beckett, Tom Luk, Rong Chen
  • Patent number: 8165179
    Abstract: The radiance of a laser is a function of drive current. The radiance is also a function of other factors, such as age and temperature. A laser projection device adjusts laser drive parameters using a gradient descent operation. The device parameters may be adjusted iteratively and periodically. The period may be shorter or longer than a scan line in a video image.
    Type: Grant
    Filed: December 23, 2008
    Date of Patent: April 24, 2012
    Assignee: Microvision, Inc.
    Inventors: Margaret K. Brown, Joel D. Hopkins, Jenchao J. Lin, Lifford McLauchlin
  • Patent number: 8160113
    Abstract: Output pulses from an optical system having a seed source and an optical amplifier coupled to the seed source may be controlled by controlling a power of a seed signal from the seed source. The seed signal may be varied between a minimum value and a maximum value in a way that the seed signal exhibits one or more pulse bursts. Each pulse burst may contain one or more pulses. During an inter-pulse period between successive pulses within a pulse burst or between successive pulse bursts, the power of the seed signal may be adjusted to an intermediate value that is greater than the minimum value and less than the maximum value. The intermediate value is chosen to control a gain in the optical amplifier such that a pulse or pulse burst that follows the period exhibits a desired behavior.
    Type: Grant
    Filed: July 21, 2009
    Date of Patent: April 17, 2012
    Assignee: Mobius Photonics, Inc.
    Inventors: Frank J. Adams, Manuel J. Leonardo, David L. Klein
  • Patent number: 8121159
    Abstract: A temperature compensation method for laser power in an optical disk drive is provided. A predetermined linear-fitting power curve and a temperature-changing slope curve are previously stored in the optical disk drive. Firstly, an output of laser power is controlled according to the predetermined linear-fitting power curve to read/write data. Next, the temperature of the disk drive is detected. Then, whether the temperature has changed is checked. If the temperature has not changed, the method continues to read/write data. If the temperature has changed, the method obtains a relative slope from the slope curve by use of the temperature of the disk drive, displaces the slope of the predetermined linear-fitting power curve with the obtained relative slope to form a new linear-fitting power curve for replacing the predetermined linear-fitting power curve, and controls the output of laser power.
    Type: Grant
    Filed: October 21, 2008
    Date of Patent: February 21, 2012
    Assignee: Quanta Storage Inc.
    Inventors: Chia-Hsing Hsu, Yi-Long Hsiao
  • Patent number: 8094693
    Abstract: A laser control method includes the steps of: using a laser control circuit which includes a constant current circuit that maintains a constant current flowing through a semiconductor laser element, and which includes an adder and a multiplier connected to a stage preceding the constant current circuit, and using detection means for calibration for detecting an applied laser output; calculating, on the basis of a detection signal output from the detection means, a reference bias value and a reference gain value for obtaining a specified laser output with respect to a specified input to the multiplier; inputting the reference bias value and the reference gain value to the adder and the multiplier, respectively; and controlling the applied laser output from the semiconductor laser element by performing calibration.
    Type: Grant
    Filed: November 25, 2009
    Date of Patent: January 10, 2012
    Assignee: Sony Disc & Digital Solutions Inc.
    Inventors: Kunio Nakayama, Koji Ishiwata, Cheonseok Park
  • Patent number: 8080773
    Abstract: The present invention relates to a method of measuring backward light, which is constructed for checking, prior to laser processing, backward light that propagates backward through an isolator included in a laser processing apparatus. The present invention also relates to a laser processing method and the like. A laser processing apparatus has an optical head provided with a laser light source part, light guide, and isolator. The optical head has an emitting optical system, irradiation optical system, and light collecting optical system. The method of measuring backward light uses a photodetector to detect, from reference light introduced from a measurement light source into the optical head, the power of an optical component that has passed through the isolator, while changing the position of the measurement light source.
    Type: Grant
    Filed: February 25, 2009
    Date of Patent: December 20, 2011
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Shinobu Tamaoki, Motoki Kakui, Kazuo Nakamae
  • Patent number: 8073026
    Abstract: A chirped pulse amplification laser system. The system generally comprises a laser source, a pulse modification apparatus including first and second pulse modification elements separated by a separation distance, a positioning element, a measurement device, and a feedback controller. The laser source is operable to generate a laser pulse and the pulse modification apparatus operable to modify at least a portion of the laser pulse. The positioning element is operable to reposition at least a portion of the pulse modification apparatus to vary the separation distance. The measurement device is operable to measure the carrier envelope phase of the generated laser pulse and the feedback controller is operable to control the positioning element based on the measured carrier envelope phase to vary the separation distance of the pulse modification elements and control the carrier envelope phase of laser pulses generated by the laser source.
    Type: Grant
    Filed: June 21, 2007
    Date of Patent: December 6, 2011
    Assignee: Kansas State University Research Foundation
    Inventors: Zenghu Chang, Chengquan Li, Eric Moon
  • Patent number: 8073021
    Abstract: A method for operating a frequency converted light source includes sweeping a wavelength control signal of a semiconductor laser over an initial signal range and measuring an optical power of an output beam emitted from a wavelength conversion device coupled to the semiconductor laser. The wavelength control signal of the semiconductor laser may then be swept over at least one truncated signal range and the optical power of the resulting output beam is measured. The at least one truncated signal range may be centered on a point corresponding to a maximum power of the output beam of the sweep of the wavelength control signal over the preceding signal range. An operational signal range for the wavelength control signal is determined such that a midpoint of the operational signal range corresponds to the maximum optical power of the resulting output beam of the sweep over the preceding signal range.
    Type: Grant
    Filed: June 2, 2009
    Date of Patent: December 6, 2011
    Assignee: Corning Incorporated
    Inventors: Vikram Bhatia, Dragan Pikula, Madhan Mothi Raj
  • Patent number: 8050301
    Abstract: Systems and methods for stabilizing laser frequency based on an isoclinic point of an atomic or molecular medium are provided herein. A system may include: a transmission cell containing a gas and configured to transmit light from the laser, the gas having an absorption spectrum with an isoclinic point; a photodiode generating an output based on an amplitude of transmitted laser light; and circuitry configured to tune the frequency of the laser to the isoclinic point of the absorption spectrum based on the output. The absorption spectrum may have first and second overlapping peaks respectively corresponding to first and second transitions of the gas, the isoclinic point being a saddle point between the first and second peaks. The first and second peaks may have substantially equal amplitude as one another and/or may broaden substantially equally as each other as a function of a physical parameter of the gas.
    Type: Grant
    Filed: February 9, 2010
    Date of Patent: November 1, 2011
    Assignee: The Aerospace Corporation
    Inventors: Nathan P. Wells, James C. Camparo
  • Publication number: 20110255564
    Abstract: An image display device including a laser light source device that includes: laser elements of different output wavelengths; a pulse signal generating unit that generates pulse signals based on a video signal; a laser driving unit that drives the laser elements in synchronization with the pulse signals; an optical combining system that combines laser beams, outputs a combined laser beam, and retrieves part of the combined laser beam; a light amount measuring unit that measures a light amount of a retrieved laser beam; and a light amount adjusting unit that causes the laser driving unit to individually adjust a light amount for the each laser element based on a measurement value, wherein the pulse signal generating unit operates in a light amount measuring mode so that emission timings would not coincide one another, and the light amount measuring unit individually measures a light amount of the each laser element.
    Type: Application
    Filed: March 23, 2011
    Publication date: October 20, 2011
    Inventor: Hitoshi CHIHARA
  • Publication number: 20110249692
    Abstract: Apparatus and method for control of lasers (which use an array of optical gain fibers) in order to improve spectrally beam-combined (SBC) laser beam quality along the plane of the SBC fiber array via spectral-to-spatial mapping of a portion of the spectrally beam-combined laser beams, detection of optical power in each of the spatially dispersed beams and feedback control of the lasers for wavelength-drift correction. The apparatus includes a diffractive element; a source of a plurality of substantially monochromatic light beams directed from different angles to a single location on the diffractive element, wherein the diffractive element spectrally combines the plurality of light beams into a single beam. A controller adjusts characteristics of the light beams if one of the light beams has become misadjusted. In some embodiments, the controller adjusts the wavelength tuning of the respective fiber laser.
    Type: Application
    Filed: April 12, 2011
    Publication date: October 13, 2011
    Applicant: LOCKHEED MARTIN CORPORATION
    Inventors: Eric C. Honea, Donald R. Jander, Pratheepan Madasamy, Tolga Yilmaz
  • Publication number: 20110228801
    Abstract: Disclosed is a high current radiation system. The system includes a high current radiation source to generate radiation and an analog circuit to generate, based, at least in part, on an input signal representative of the present current level delivered to the high current radiation source and a user-controlled input representative of a desired current level, an output signal to control a current level to be delivered to the high current radiation source. The system further includes a current driver to control the current delivered to the high current radiation source based, at least in part, on the output signal of the analog circuit.
    Type: Application
    Filed: June 1, 2011
    Publication date: September 22, 2011
    Applicant: Lumenis Ltd.
    Inventor: Ofer Weizmann
  • Patent number: 8000358
    Abstract: A power monitoring system uses a low loss reflective element to partially split the output laser beams from an array of laser sources, in a parallel configuration, to produce a monitor beams for each laser source. Each of these monitor beams may propagate within the reflective element in a lossless manner under total internal reflection and into one of a plurality of photodiodes that sense an optical characteristic such as output beam intensity, where this sensed signal is then used as part of a feedback control to control operation of the laser sources in the array.
    Type: Grant
    Filed: April 20, 2009
    Date of Patent: August 16, 2011
    Assignee: Emcore Corporation
    Inventor: William H. Wang
  • Patent number: 7995630
    Abstract: This invention relates to opto-electronic systems using semiconductor lasers driven by optical phase-locked loops that control the laser's optical phase and frequency. Feedback control provides a means for precise control of optical frequency and phase, including the ability for broadband electronic tunability of optical signals and the cascading of multiple lasers for enhanced tunability and coherent combining for increased output power.
    Type: Grant
    Filed: April 1, 2009
    Date of Patent: August 9, 2011
    Inventor: George A. Rakuljic
  • Patent number: 7986720
    Abstract: A circuit for driving a light-emitting element such as a laser diode LD has a boost circuit for boosting an input voltage to supply it to the light-emitting element, a photoreceptor such as a photodiode PD for monitoring light from the light-emitting element; and a boost control circuit for controlling a boost voltage of the boost circuit based on a monitored amount of the photoreceptor. In the method for driving a light-emitting element by boosting an input voltage to supply the voltage to the light-emitting element, light from the light-emitting element is monitored and its monitored amount is used as a basis to control a boost voltage to the light-emitting element. A control circuit may be provided to control a driving current that passes through the light-emitting element based on the monitored amount of the photoreceptor.
    Type: Grant
    Filed: June 25, 2009
    Date of Patent: July 26, 2011
    Assignee: NEC Corporation
    Inventor: Masashi Tachigori
  • Patent number: 7970029
    Abstract: Semiconductor lasers are driven such that high output laser beams are stably obtained without a long start up time. The light outputs of a plurality of semiconductor lasers are detected by photodetectors. The semiconductor lasers are driven by automatic power control based on comparison results between the output of the photodetectors and a set value corresponding to a target light output for the semiconductor lasers. A correction pattern that corrects the set value and/or the output of the photodetectors such that the actual light output becomes uniform is generated in advance. The set value and/or the output are varied according to the correction pattern for a predetermined period of time from initiation of drive. A single correction pattern is employed in common with respect to the plurality of semiconductor lasers.
    Type: Grant
    Filed: October 5, 2006
    Date of Patent: June 28, 2011
    Assignee: Fujifilm Corporation
    Inventor: Yuichi Teramura
  • Patent number: 7967452
    Abstract: A projection type display apparatus is provided that is safe even when a person looks directly into a laser beam. A laser operation control unit sets the output power of at least one laser source so that intensity A (mW/mm2) of the laser beam on at least one spatial light modulation element satisfies relationship of A<686×B2 when numerical aperture B on image side of an illumination optics system is set.
    Type: Grant
    Filed: August 24, 2006
    Date of Patent: June 28, 2011
    Assignee: Panasonic Corporation
    Inventors: Tatsuo Itoh, Kazuhisa Yamamoto, Kenichi Kasazumi, Kiminori Mizuuchi
  • Patent number: 7961772
    Abstract: A laser system according to the invention comprises pump generating means (x02, x03) for generating at least a first and a second, preferably focused, pump beam, and lasing means (x06, x07) for emitting radiation by being appropriately pumped. The lasing means (x06, x07) is disposed in a first resonator so as to receive the first pump beam in order to generate a first beam (x21) having a first frequency, and the lasing means (x06, x07) is disposed in a second resonator so as to receive the second pump beam in order to generate a second beam (x22) having a second frequency. At least one Q-switch (x08; x17, x18) is disposed in the first and the second resonator, so that the first beam and the second beam both pass a Q-switch (x08; x17, x18). The laser system (x01) has an output (x13) generated from said first beam (x21) and said second beam (x22), and at least a part of said output (x13) is fed back to a regulation system (x14), said regulation system (x14) controlling said pump generating means (x02, x03).
    Type: Grant
    Filed: July 10, 2007
    Date of Patent: June 14, 2011
    Assignee: Advalight
    Inventors: Peter Tidemand-Lichtenberg, Morten Thorhauge, Jesper Liltorp Mortensen
  • Patent number: 7957438
    Abstract: A method for monitoring laser light launched into a core of a single mode fiber includes launching a portion of light directly into the cladding about the core. The cladding launched light is a known fraction of the core launched light and can be monitored by placing a detector about the cladding. Detected light including light that was launched into the cladding and has leaked through the cladding is used as a known fraction of light in the core and can be used to control the laser light source. This can be done with a straight section of single mode optical fiber and does not require bending the fiber. Advantageously, most of the core launched light remains in the core as guided light.
    Type: Grant
    Filed: December 16, 2008
    Date of Patent: June 7, 2011
    Assignee: JDS Uniphase Corporation
    Inventors: David Simons, Boris Kharlamov, James Wong, Vincent Issier, Andy Miller, James Nunley
  • Publication number: 20110129227
    Abstract: An apparatus comprising a laser transmitter having a first side and a second side, a filter coupled to the first side, a detector coupled to the second side, and a temperature controller coupled to the laser transmitter and the detector. Also disclosed is an apparatus comprising at least one processor configured to implement a method comprising receiving a photocurrent of a backward light from a laser, determining a wavelength shift offset between a wavelength of the output light and a filter transmission peak, and adjusting a temperature of the laser to substantially reduce the wavelength shift and align the wavelength of the output light with the filter transmission peak.
    Type: Application
    Filed: December 2, 2009
    Publication date: June 2, 2011
    Applicant: Futurewei Technologies, Inc.
    Inventors: Yang Jing Wen, Jizhong Liu, Yu Sheng Bai
  • Patent number: 7953126
    Abstract: A fiber laser processing apparatus controls a LD drive current ILD in a power feedback control mode (FIG. 3E) such that output of a fiber laser beam FB rises substantially from zero or a value around zero to a preceding level having no substantial effect on laser processing and arrives at a desired level (PA) for the laser processing from a preceding level PB after a first time period (preceding pulse width TB) has elapsed (time point t2 of FIGS. 3A to 3F) from the start of the rising to the preceding level (time point t1 of FIGS. 3A to 3F), and this may effectively prevent occurrence of a high-peak pulse HP at the rising edge of the fiber laser beam FB (FIG. 3F).
    Type: Grant
    Filed: June 15, 2009
    Date of Patent: May 31, 2011
    Assignee: Miyachi Corporation
    Inventor: Nobuyuki Yamazaki
  • Patent number: 7940820
    Abstract: A method of protecting a laser against damage caused by undesired incident light in a resonator includes measuring a parameter, which is a measure for the optical power of the incident light. In more concrete terms, the optical power occurring at a resonator mirror is measured. In response to a result of the measurement, a pumping power for the laser is reduced to reduce the optical power in the resonator to a value that is uncritical for the laser.
    Type: Grant
    Filed: May 20, 2008
    Date of Patent: May 10, 2011
    Assignee: Heidelberger Druckmaschinen AG
    Inventor: Claus Seibert
  • Publication number: 20110103415
    Abstract: An optical device comprising a 1×2 optical coupler on a planar substrate and a waveguide on the planar substrate, the waveguide having a first arm and a second arm coupled to the 1×2 optical coupler. The device also comprises an optical resonator on the planar substrate, wherein the optical resonator is optically coupled to the first arm and the optical resonator is substantially athermalized.
    Type: Application
    Filed: November 3, 2009
    Publication date: May 5, 2011
    Applicant: Alcatel-Lucent USA, Incorporated
    Inventor: Mahmoud Rasras
  • Patent number: 7920609
    Abstract: In an exposure device comprising a laser controller that is configured as a circuit board capable of independently being changed, and that controls the emission of laser light from a laser emitter emitting laser light on receipt of an instruction for control given from a main controller responsible for overall control of the operation of the exposure device, error control information that is obtained in advance with regard to the circuit board and controls variations of a controlling factor due to a circuit error of the circuit board is stored into a memory provided to the laser controller prior to the provision of the circuit board to the exposure device. On receipt of an instruction for control given from the main controller to cause the emission of laser light in a predetermined amount of light, the laser controller determines a condition of emission of laser light based on the error control information stored in the memory to cause the laser emitter to emit laser light under the condition of emission.
    Type: Grant
    Filed: April 18, 2008
    Date of Patent: April 5, 2011
    Assignee: Dainippon Screen Mfg. Co., Ltd.
    Inventors: Toshimitsu Hamagishi, Mamoru Fujimoto
  • Patent number: 7920608
    Abstract: A highly portable, high-powered infrared laser source is produced by intermittent operation of a quantum cascade laser power regulated to a predetermined operating range that permits passive cooling. The regulation process may boost battery voltage allowing the use of more compact, low-voltage batteries.
    Type: Grant
    Filed: March 11, 2008
    Date of Patent: April 5, 2011
    Assignee: Daylight Solutions, Inc.
    Inventors: Rob Marsland, Jr., Timothy Day
  • Patent number: 7907650
    Abstract: A laser module includes a semiconductor laser, an output optical system provided on an optical output side of the semiconductor laser, a temperature detecting element that detects a temperature of the output optical system; and an output controller that calculates a drive current to set an optical output intensity of the laser module at a desired value on the basis of temperature information obtained by the temperature detecting element, and outputs the drive current to the semiconductor laser.
    Type: Grant
    Filed: March 30, 2006
    Date of Patent: March 15, 2011
    Assignee: Eudyna Devices Inc.
    Inventors: Haruyoshi Ono, Isao Baba
  • Patent number: 7899096
    Abstract: A method for aligning an optical package includes applying a dither waveform and an advancement waveform to a drive mechanism. The optical package includes a semiconductor laser operable to emit an output beam with a first wavelength, a wavelength conversion device operable to convert the output beam to a second wavelength, adaptive optics configured to optically couple the output beam into a waveguide portion of an input facet of the wavelength conversion device, and a drive mechanism coupled to the adaptive optics and configured to adjust a position of the output beam. The dither waveform oscillates the adaptive optics back and forth in first and second directions to oscillate the output beam on the input facet. The advancement waveform advances the adaptive optics in an adjustment direction. Rising and falling edge times of the dither waveform are greater than rising and falling edge times of the advancement waveform.
    Type: Grant
    Filed: October 30, 2009
    Date of Patent: March 1, 2011
    Assignee: Corning Incorporated
    Inventors: Vikram Bhatia, David Gustave Ehrenberg, Dragan Pikula
  • Patent number: 7899095
    Abstract: A method and apparatus may comprise a seed laser, along with an amplifier laser amplifying the output of the seed laser. A bandwidth metrology module may provide a bandwidth measurement and a bandwidth error signal may be provided using a bandwidth set point. A differential timing system responsive to the error signal can selectively adjust a differential firing time between the seed laser and amplifier laser. A beam dimension and center wavelength control system may adjust a beam dimension, within the cavity of the seed laser, to select bandwidth, and may adjust center wavelength at the same time, using a plurality of beam expansion prisms and at least one other prism or other optical element in the cavity to select center wavelength.
    Type: Grant
    Filed: April 9, 2008
    Date of Patent: March 1, 2011
    Assignee: Cymer, Inc.
    Inventor: William N. Partlo
  • Patent number: 7894494
    Abstract: An apparatus and method which may comprise a seed laser defining an optical cavity producing an output. An amplifier may amplify the seed laser output. A bandwidth error signal generator may provide a bandwidth error signal from measured bandwidth and a target. A bandwidth selection element, which may comprise an adjustable sized aperture external to the cavity of the seed laser may selectively alter the bandwidth of the seed laser output. A bandwidth control system may control the bandwidth control element and also selectively adjust a differential firing time between the seed laser and amplifier or another bandwidth selection actuator to cooperated (coarsely or finely) with the bandwidth selection element to control bandwidth of the laser system.
    Type: Grant
    Filed: April 9, 2008
    Date of Patent: February 22, 2011
    Assignee: Cymer, Inc.
    Inventor: Toshihiko Ishihara
  • Patent number: 7889772
    Abstract: A laser output power command determination value from a controller (17) is input to an upper limit current determination unit (32), and an upper limit current value to be decided based on the laser output power command determination value is determined. Then, a second comparator (30) compares a command current value determined from the laser output power command determination value and a laser output power command determination value measured with a power monitor (13), with an upper limit current value determined with a upper limit current determination unit (32). The second comparator (30) determines a command current value when the upper limit current value is greater than the command current value and the upper limit current value when the command current value is greater than the upper limit current value, as a reference current value, by which reference current value a current to be supplied to pumping means is configured to be controlled.
    Type: Grant
    Filed: April 25, 2006
    Date of Patent: February 15, 2011
    Assignee: Mitsubishi Electric Corporation
    Inventors: Toshiki Koshimae, Toshiaki Watanabe, Takeshi Morimoto
  • Patent number: 7885308
    Abstract: A gas discharge laser includes a laser housing including a laser gas and an electrode-assembly for lighting a discharge in the laser gas. The electrode assembly has a first resonant frequency when the discharge is not lit and a second resonant frequency when the discharge is lit. RF power delivering circuitry of the laser includes an arrangement for determining and recording the two resonant frequencies. RF power is applied to the electrodes at the first recorded resonant frequency to facilitate lighting of the discharge, and thereafter at the second resonant frequency to light and sustain the discharge.
    Type: Grant
    Filed: April 1, 2009
    Date of Patent: February 8, 2011
    Assignee: Coherent, Inc.
    Inventors: W. Shef Robotham, Jr., Joel Fontanella
  • Patent number: 7876794
    Abstract: The present invention discloses a laser light source for implementing pulsed oscillation of laser light, which has a laser cavity in which a laser medium for generating emitted light with supply of excitation energy is placed on a resonance path; an excitation device for continuously supplying excitation energy to the laser medium; a monitor part for monitoring a power of light extracted at a middle point of the path of the cavity from the laser medium in accordance with the supply of the excitation energy by the excitation device; a Q-switch for modulating a cavity loss of the laser cavity; and a control part for performing such control as to stabilize a peak power or an energy of laser light pulses outputted in a state in which the cavity loss of the laser cavity is set at a second predetermined loss for oscillation of high-power pulses, based on the power of the emitted light monitored by the monitor part in a state in which the cavity loss of the laser cavity is set at a first predetermined loss for non-o
    Type: Grant
    Filed: September 29, 2006
    Date of Patent: January 25, 2011
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Motoki Kakui
  • Patent number: 7873083
    Abstract: A system, apparatus, and method may provide laser beams of two or more wavelengths from diode pumped solid-state laser sources (220, 222, 224). The beam paths of these laser beams with different wavelengths, which are generated by the laser sources (220, 222, 224), may be aligned along a common optical axis 280 by an optical configuration, to treat at least one target area. Frequency-doubled laser beams, output from a plurality of diode pumped solid state laser cavities, may be passed through fold mirrors (M2, M5, M8), and combined on a common optical axis 280, using one or more combiner mirrors (M10, M11, M12), to unify the beam paths. Selected laser beams may be delivered to a target using one or more delivery systems.
    Type: Grant
    Filed: October 16, 2003
    Date of Patent: January 18, 2011
    Assignee: Lumenis Ltd.
    Inventors: David Haydn Mordaunt, Steven Scott Christensen, Allison Albrecht Ferro, David A. Dewey
  • Patent number: 7873081
    Abstract: A tunable laser cavity utilizes a dispersion compensated acousto-optic tunable filter. The wavelength accuracy and stability is achieved by a wavelength locker utilizing two separate intracavity light beams without the need to use beam splitters to significantly reduce the space typically needed by a conventional wavelength locker, and provide more stable operation and easy assembly. The acoustic optical tunable filter is constructed in such a way that two transducers are bonded on the same crystal opposite to each other to create two counter propagating acoustic waves. Dispersion occurs after the collimated light diffracted by the first acoustic wave and is compensated by the second acoustic wave traveling in the opposite direction. By using different laser gain mediums, acoustic wave driving frequencies and acousto-optical crystals, this invention can be used to make tunable lasers in wide range of optical wavelengths.
    Type: Grant
    Filed: November 17, 2008
    Date of Patent: January 18, 2011
    Inventor: Peiliang Gao
  • Patent number: 7869472
    Abstract: Techniques and devices for providing optical locking of optical resonators and lasers.
    Type: Grant
    Filed: March 11, 2009
    Date of Patent: January 11, 2011
    Assignee: OEwaves, Inc.
    Inventors: Lute Maleki, Andrey B. Matsko, Anatoliy Savchenkov, Vladimir Ilchenko, Wei Liang, David Seidel, Jerry Byrd
  • Patent number: 7864824
    Abstract: Provided is a multiple distributed feedback laser device. The laser device includes an active layer, a first diffraction grating, and a second diffraction grating. The substrate includes a first distributed feedback region, a modulation region, and a second distributed feedback region. The first diffraction grating is coupled to the active layer in the first distributed feedback region. The second diffraction grating is coupled to the active layer in the second distributed feedback region. In addition, the laser device includes a first micro heater and a second micro heater. The first micro heater supplies heat to the first diffraction grating. The second micro heater supplies heat to the second diffraction grating. The first micro heater and the second micro heater are controlled independently from each other.
    Type: Grant
    Filed: July 20, 2009
    Date of Patent: January 4, 2011
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Kyung Hyun Park, Jaeheon Shin, Namje Kim, Chul-Wook Lee, Eundeok Sim, Sang-Pil Han, Yongsoon Baek
  • Patent number: 7848370
    Abstract: Semiconductor diode lasers are phase-locked by direct current injection and combined to form a single coherent output beam. The optical power is amplified by use of fiber amplifiers. Electronically control of the optical phases of each emitter enables power efficient combining of output beams to be maintained under dynamic conditions.
    Type: Grant
    Filed: January 25, 2008
    Date of Patent: December 7, 2010
    Assignee: Telaris Inc.
    Inventors: Anthony S. Kewitsch, George A. Rakuljic
  • Patent number: 7843977
    Abstract: A light source and the method for operating the same are disclosed. The light source includes first and second lasers, and first and second wavelength control assemblies. The lasers emit first and second light beams, respectively, at wavelengths that are determined by first and second wavelength control signals. First and second beam splitters split the first and second light beams, respectively, to create first and second sampling light beams. The first and second wavelength control assemblies receive sampling light beams and generate the first and second wavelength control signals such that the wavelengths of the first and second light beams differ by no more than a predetermined amount. The first and second wavelength control assemblies each include an absorption cell having a gas that has an optical absorption that varies with the wavelength of the first and second sampling light beams at wavelengths around the output wavelength of the light source.
    Type: Grant
    Filed: June 19, 2008
    Date of Patent: November 30, 2010
    Assignee: Agilent Technologies, Inc.
    Inventors: Eric Stephen Johnstone, Miao Zhu, Tirumala R. Ranganath
  • Patent number: 7839906
    Abstract: Exemplary embodiments provide a method and system for controlling laser power in an optical disc drive. The exemplary embodiment of a control system includes at least one control component for generating a control signal; a plant for generating a control output responsive to the control signal; and a dual feedback control loop coupled between the control output of the plant and the control component, the dual feedback control loop comprising a combination of a running optimal power control (ROPC) loop, and an automatic power control (APC) loop that run concurrently for generating respective feedback control signals that are input to the control component for generation of a combined control signal adjustment that is used at least in part to generate the control signal.
    Type: Grant
    Filed: June 6, 2007
    Date of Patent: November 23, 2010
    Assignee: Marvell International Ltd.
    Inventors: Pantas Sutardja, Christopher Painter
  • Publication number: 20100272127
    Abstract: There is provided a laser apparatus that includes a laser emitter configured to emit a laser emitter output beam. The apparatus includes a transmissive grating positioned with the laser emitter output beam incident upon the grating. The grating transmits a first order output beam. The apparatus includes a feedback element positioned with the first order emitted beam incident upon the feedback element. The feedback element returns a feedback element return beam incident upon the grating. The feedback element transmits a feedback element output beam at a feedback element output beam width. The laser apparatus includes a pin-hole element with a pin-hole positioned with the feedback element output beam incident upon the pin-hole. The feedback element output beam width is not greater than the pin-hole width. The pin-hole element transmits a pin-hole output beam at a pin-hole element output beam width less than the feedback element output beam width.
    Type: Application
    Filed: April 23, 2009
    Publication date: October 28, 2010
    Inventors: Tony Lam, ChenChun Wu
  • Publication number: 20100272135
    Abstract: A method of operating a frequency-converted laser source is provided. According to the method, the gain section of a laser diode is driven such that the pulse repetition frequency ?P of the laser source is less than but sufficiently close to a mathematical reciprocal of the round-trip light flight time tF of the external laser cavity of the laser source, or an integer multiple thereof. In this manner, respective self-seeding laser pulses generated from the pulsed optical pump signal reach the gain section of the laser diode during buildup of successive optical pump signal pulses. Additional embodiments are disclosed and claimed.
    Type: Application
    Filed: April 28, 2009
    Publication date: October 28, 2010
    Inventors: Dmitri Vladislavovich Kuksenkov, Shenping Li
  • Patent number: 7822084
    Abstract: According to aspects of an embodiment of the disclosed subject matter, method and apparatus are disclose that may comprise adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, without utilizing any beam magnification control, or adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, while utilizing beam magnification control for other than bandwidth control, and adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, while utilizing beam magnification control for bandwidth control based on the error signal.
    Type: Grant
    Filed: April 9, 2008
    Date of Patent: October 26, 2010
    Assignee: Cymer, Inc.
    Inventors: Kevin M. O'Brien, Robert N. Jacques
  • Patent number: 7822096
    Abstract: A method of operating a laser projection system is provided. The projection system comprises an external cavity laser, an optical intensity monitor, laser projection optics, and a controller. The external cavity laser comprises a laser diode, an intra-cavity wavelength conversion device, and a wavelength selective element. According to the method, the position of the wavelength selective element is adjusted relative to an optical axis Z of the external cavity laser to optimize output intensity. Specifically, the position of the wavelength selective element is adjusted by (i) tilting the wavelength selective element about its wavelength selective axis Y to reflect a wavelength of interest along an optimum path in an XZ plane of the external laser cavity and (ii) tipping the wavelength selective element about its wavelength insensitive axis X to reflect the wavelength of interest along an optimum path in a YZ plane of the external laser cavity. Additional embodiments are disclosed and claimed.
    Type: Grant
    Filed: December 12, 2008
    Date of Patent: October 26, 2010
    Assignee: Corning Incorporated
    Inventor: Dmitri Vladislavovich Kuksenkov
  • Publication number: 20100265974
    Abstract: A power monitoring system uses a low loss reflective element to partially split the output laser beams from an array of laser sources, in a parallel configuration, to produce a monitor beams for each laser source. Each of these monitor beams may propagate within the reflective element in a lossless manner under total internal reflection and into one of a plurality of photodiodes that sense an optical characteristic such as output beam intensity, where this sensed signal is then used as part of a feedback control to control operation of the laser sources in the array.
    Type: Application
    Filed: April 20, 2009
    Publication date: October 21, 2010
    Applicant: EMCORE CORPORATION
    Inventor: William Wang
  • Patent number: 7809034
    Abstract: The present invention provides an auto-power control (APC) circuit and a method to stabilize the extinction ratio of an optical output from a laser diode (LD) in an optical transmitter. The APC circuit according to the invention includes two feedback loops for the modulation IM and the bias current IB each having variable loop gain. The extinction ratio of the optical output from the LD is kept constant by setting the ratio of the loop gains of respective APC circuits to be ER?1.
    Type: Grant
    Filed: February 14, 2008
    Date of Patent: October 5, 2010
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Keiji Tanaka
  • Patent number: RE43422
    Abstract: A tunable optical local oscillator is used for optical heterodyne signal detection using an electrooptic Mach-Zehnder modulator to produce a rapidly tunable optical signal from a tunable RF frequency generator. A combination of the Mach-Zehnder modulator and optical fibers for providing stimulated Brillouin scattering are used to suppress unwanted signals for providing a spectrally pure optical local oscillator waveform. Suppression of unwanted optical signals, up to 50 dB, generated by the Mach-Zehnder modulator is obtained, resulting in high spectral purity of the optical local oscillator waveform with an extended tuning range of the tunable optical oscillator equal to the operating bandwidth of up to 60 GHz of the Mach-Zehnder modulators.
    Type: Grant
    Filed: June 14, 2007
    Date of Patent: May 29, 2012
    Assignee: The Aerospace Corporation
    Inventors: David A. Kozlowski, John A. Hurrell