Frequency Patents (Class 372/32)
  • Patent number: 10389429
    Abstract: A full-duplex analog relay may comprise an analog uplink relay and an analog downlink relay, and may relay signals between a transmitter and a backscatter node. The spectrum of the downlink signal transmitted by the downlink relay may be different than the spectrum of the uplink signal received by the uplink relay. Filtering may attenuate leakage from the downlink relay to the uplink relay, and vice versa. The uplink relay may create a phase offset that is opposite in sign and substantially equal in magnitude to the phase offset created by the downlink relay. The downlink and uplink relays, taken together, may created a substantially constant net phase offset. The full-duplex relay may be housed in a vehicle that moves, and may be used to determine spatial coordinates of backscatter sources that are located in the relay's environment.
    Type: Grant
    Filed: February 12, 2018
    Date of Patent: August 20, 2019
    Assignee: Massachusetts Institute of Technology
    Inventors: Yunfei Ma, Nicholas Selby, Fadel Adib
  • Patent number: 10281747
    Abstract: A low-cost, robust method for automatically tuning a coupled resonator to match a wavelength of electromagnetic radiation emitted from an applied laser source. Dithering signals are used for automatic wavelength tuning and thermal stabilization of microring resonators. The disclosed method can be applied using low-speed analog and digital circuitry, to create a complete photonic interconnection network. The methods disclosed also automatically detect, measure, and correct for resonance shift.
    Type: Grant
    Filed: July 16, 2015
    Date of Patent: May 7, 2019
    Assignee: THE TRUSTEES OF COLUMBIA UNIVERSITY IN THE CITY OF NEW YORK
    Inventors: Kishore Padmaraju, Keren Bergman
  • Patent number: 10256934
    Abstract: A technique for optical signal transmission includes generating a plurality of double sideband modulated optical signals by modulating a plurality of source data signals using a plurality of direct modulation laser (DML) optical sources, wherein the plurality of double sideband modulated optical signals occupy non-overlapping neighboring optical frequency bands, generating a chirp-managed laser (CML) output signal by multiplexing the plurality of double sideband modulated optical signals using a wavelength-selective multiplexer, and transmitting the CML output signal over an optical transport medium.
    Type: Grant
    Filed: October 10, 2017
    Date of Patent: April 9, 2019
    Assignee: ZTE Corporation
    Inventors: Jianjun Yu, Hung-Chang Chien
  • Patent number: 10251234
    Abstract: A thermal management system for an object comprising: one or more thermoelectric elements, one or more light emitting sources, electricity transport medium; electrical energy storage, and a controller. Heat energy that is generated or absorbed by the object is converted by said thermoelectric element to electrical energy. This energy is transferred to light emitting source to emit the energy to the environment or delivered to the electrical energy storage or back to the thermoelectric elements using the electricity transport medium and the controller to achieve the thermal goal of the thermal management system.
    Type: Grant
    Filed: June 24, 2016
    Date of Patent: April 2, 2019
    Inventor: David Hirshberg
  • Patent number: 10132747
    Abstract: An absorption spectrometer which measures a gas component concentration in a measured gas and which operates via wavelength modulation spectroscopy, wherein the light wavelength of a wavelength-tunable light source is periodically varied over a gas component absorption line of interest and simultaneously sinusoidally modulated with a high frequency and a low amplitude signal, and wherein the measurement signal of a detector is demodulated in a phase-sensitive manner at the frequency and/or a harmonic of the frequency and further analyzed, where modulation starts in each period or each n-th period with the frequency in a time interval before the beginning of the time function and is performed with a higher amplitude than during the time function to demodulate the measurement signal in a phase-synchronous manner, where a device provided for the phase-sensitive demodulation is synchronized during the time interval such that a cable for transmitting synchronization signals is no longer necessary.
    Type: Grant
    Filed: December 2, 2015
    Date of Patent: November 20, 2018
    Assignee: Siemens Aktiengesellschaft
    Inventor: Franz Steinbacher
  • Patent number: 10122144
    Abstract: Provided is a solar-pumped fiber laser device that includes: a first layer of a light guiding material or a fluorescent material having a circular or an elliptical planar contour with an even thickness; and an optical fiber wound around a peripheral thickness edge of the first layer, wherein the optical fiber is irradiated with light formed of solar light having entered a flat surface of the planar contour of the first layer, the solar light being scattered by the light guiding material, or with fluorescence generated by applying the solar light having entered the flat surface of the planar contour of the first layer to the fluorescent material.
    Type: Grant
    Filed: November 15, 2017
    Date of Patent: November 6, 2018
    Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventor: Taizo Masuda
  • Patent number: 10096967
    Abstract: Wafer positioning errors in stepper-scanners contribute to imaging defects. Changing the wavelength of the light source's generated light can compensate for wafer positional errors in the Z-direction. The wafer's real-time z-position is determined and a change in wavelength target to offset this error is communicated to the light source. The light source uses this change in wavelength target in a feed-forward operation and, in an embodiment, in combination with existing feedback operations, on a pulse-by-pulse basis for subsequent pulses in a current burst of pulses in addition to receiving the newly-specified laser wavelength target for a subsequent burst of laser pulses.
    Type: Grant
    Filed: December 7, 2016
    Date of Patent: October 9, 2018
    Assignee: Cymer, LLC
    Inventors: Rahul Ahlawat, Thomas P. Duffey
  • Patent number: 10067405
    Abstract: An optoelectronic component for generating and radiating an electromagnetic signal exhibiting a frequency lying between 30 GHz and 10 THz referred to as a microwave frequency, comprises: a planar guide configured to confine and propagate freely in a plane XY a first and a second optical wave exhibiting an optical frequency difference, referred to as a heterodyne beat, equal to the microwave frequency, a system for injecting the optical waves into the planar guide, a photo-mixer coupled to the planar guide to generate, on the basis of the first optical wave and of the second optical wave, a signal exhibiting the microwave frequency, the photo-mixer having an elongated shape exhibiting along an axis Y a large dimension greater than or equal to half the wavelength of the signal, the injection system configured so that the optical waves overlap in the planar guide and are coupled with the photo-mixer over a length along the axis Y at least equal to half the wavelength of the signal, the photo-mixer thus being abl
    Type: Grant
    Filed: December 11, 2015
    Date of Patent: September 4, 2018
    Assignees: THALES, ALCATEL LUCENT
    Inventor: Frédéric Van Dijk
  • Patent number: 9983132
    Abstract: Apparatus and methods for fluorescence imaging using radiofrequency multiplexed excitation. One apparatus splits an excitation laser beam into two arms of a Mach-Zehnder interferometer. The light in the first beam is frequency shifted by an acousto-optic deflector, which is driven by a phase-engineered radiofrequency comb designed to minimize peak-to-average power ratio. This RF comb generates multiple deflected optical beams possessing a range of output angles and frequency shifts. The second beam is shifted in frequency using an acousto-optic frequency shifter. After combining at a second beam splitter, the two beams are focused to a line on the sample using a conventional laser scanning microscope lens system. The acousto-optic deflectors frequency-encode the simultaneous excitation of an entire row of pixels, which enables detection and de-multiplexing of fluorescence images using a single photomultiplier tube and digital phase-coherent signal recovery techniques.
    Type: Grant
    Filed: July 27, 2016
    Date of Patent: May 29, 2018
    Assignee: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Eric D. Diebold, Bahram Jalali, Brandon Buckley
  • Patent number: 9979501
    Abstract: Frequency independent isolation of duplexed ports in distributed antenna systems (DASs) is disclosed. Instead of providing a duplexer in a DAS that provides frequency dependent separation between downlink and uplink communications signals, an isolation circuit is provided. The isolation circuit is coupled to a duplexed port that provides downlink communications signals to the DAS and receives uplink communications signals from the DAS. To isolate uplink communications signals from the downlink communications path, the isolation circuit includes a directional coupler. The directional coupler provides frequency independent isolation between uplink communications signals and a downlink communications path in the DAS. Further, to isolate downlink communications signals from the uplink communications path, the isolation circuit includes at least one circulator isolator.
    Type: Grant
    Filed: April 18, 2016
    Date of Patent: May 22, 2018
    Assignee: Corning Optical Communications Wireless Ltd
    Inventors: Yury Abramov, Motti Vahedy
  • Patent number: 9971090
    Abstract: A laser source or a plurality of laser sources in a photonic integrated circuit (PIC) are provided with an electrical contact that is either segmented or is connected to a series of vernier resistor segments for supply of current to operate the laser source. In either case, at least one segment of the laser contact or at least one vernier resistor segment can be trimmed in order to vary the amount of current supplied to the laser source resulting in a change to its current density and, thus, a change in its operational wavelength while maintaining the current supplied to the laser source constant.
    Type: Grant
    Filed: August 11, 2004
    Date of Patent: May 15, 2018
    Assignee: Infinera Corporation
    Inventors: Fred A. Kish, Jr., Charles H. Joyner, David F. Welch
  • Patent number: 9941668
    Abstract: In various embodiments, wavelength beam combining laser systems incorporate etalons to establish external lasing cavities and/or to combine multiple input beams into a single output beam.
    Type: Grant
    Filed: November 11, 2016
    Date of Patent: April 10, 2018
    Assignee: TERADIODE, INC.
    Inventors: Bien Chann, James Burgess, Wang Zhou, Bryan Lochman, Francisco Villarreal-Saucedo
  • Patent number: 9825423
    Abstract: A laser-frequency stabilizer includes: a light detector that converts a laser beam passing through an iodine cell to an optical output signal, an actuator that changes a resonator length in accordance with a received output voltage, and a control unit that controls the output voltage applied to the actuator. The control unit searches for a target saturated absorption line based on the optical output signal and, when the output voltage when the target saturated absorption line is found is within a normal voltage range that is predetermined corresponding to the target saturated absorption line, locks a oscillation frequency of the laser beam to the target saturated absorption line.
    Type: Grant
    Filed: February 12, 2016
    Date of Patent: November 21, 2017
    Assignee: MITUTOYO CORPORATION
    Inventors: Ryunosuke Yano, Yusuke Shirakawa, Tatsuya Narumi
  • Patent number: 9800012
    Abstract: A control apparatus for a laser oscillator includes an abnormality determining unit which determines an abnormality of a first assembly based on a first deviation between a first laser beam output command and a first laser beam output and which determines an abnormality of a second assembly based on a second deviation between a second laser beam output command and a second laser beam output, a command unit for issuing a predetermined current command to at least one of a first power unit and a second power unit when the abnormality determining unit determines that at least one of the first assembly and the second assembly has an abnormality, and an abnormality determination stopping unit for stopping the abnormality determining unit from determining an abnormality when the predetermined current command is issued.
    Type: Grant
    Filed: December 2, 2016
    Date of Patent: October 24, 2017
    Assignee: Fanuc Corporation
    Inventor: Hiroaki Tokito
  • Patent number: 9772177
    Abstract: Optical coherence tomography (OCT) probe and system designs are disclosed that minimize the effects of mechanical movement and strain to the probe to the OCT analysis. It also concerns optical designs that are robust against noise from the OCT laser source. Also integrated OCT system-probes are included that yield compact and robust electro-opto-mechanical systems along with polarization sensitive OCT systems.
    Type: Grant
    Filed: August 7, 2012
    Date of Patent: September 26, 2017
    Assignee: Axsun Technologies LLC
    Inventors: Bartley C. Johnson, Dale C. Flanders
  • Patent number: 9641941
    Abstract: Transducers and methods for converting acoustic signals into electrical signals. A device (100) includes an interferometer (106) including two mirrors (108) adapted for reflecting electromagnetic radiation (112) coupled into a space (110) between the mirrors (108). The acoustic signal (102) is to be coupled into the space (110) for influencing the electromagnetic radiation (112) in accordance with this acoustic signal. An electromagnetic radiation detector (112) is adapted for detecting the influenced electromagnetic radiation (112) and for converting the detected influenced electromagnetic radiation (112) into the electric signal (104) being indicative for the acoustic signal (102). An operation point stabilization unit stabilizes an operation point of the device (100).
    Type: Grant
    Filed: August 20, 2015
    Date of Patent: May 2, 2017
    Assignee: XARION LASER ACOUSTICS GMBH
    Inventor: Balthasar Fischer
  • Patent number: 9627838
    Abstract: In the method of generating high power light with high efficiency and low thermal loading, the improvement comprising the steps of resonantly pumping a first thulium-doped fiber laser with a second thulium-doped fiber last, said second thulium-doped fiber laser having a shorter wavelength than said first thulium-doped fiber laser.
    Type: Grant
    Filed: March 14, 2013
    Date of Patent: April 18, 2017
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventors: Daniel J. Creeden, Benjamin R. Johnson
  • Patent number: 9587945
    Abstract: A resonator fiber optic gyroscope comprises a master laser that emits a reference optical signal, a first slave laser that emits a clockwise optical signal, and a second slave laser that emits a counter-clockwise optical signal. A resonator ring cavity in optical communication with the first slave laser and second slave laser is configured to receive the optical signals from the slave lasers without receiving the reference optical signal. A reflected optical signal from the cavity is directed to a feedback laser stabilization loop for the master laser that includes a common modulation frequency scheme. A frequency of the optical signal from the master laser is indirectly locked onto a resonance frequency of the cavity with a fixed frequency offset, which is determined by a relative frequency between the optical signal of the first slave laser or the second slave laser, and the optical signal of the master laser.
    Type: Grant
    Filed: June 23, 2014
    Date of Patent: March 7, 2017
    Assignee: Honeywell International Inc.
    Inventors: Lee K. Strandjord, Glen A. Sanders, Tiequn Qiu
  • Patent number: 9537577
    Abstract: A device may insert a set of tones into a transmitter signal at a set of frequency offsets from a set of transmitter channels associated with a set of transmitter channel wavelengths. The set of transmitter channels may include a first channel being associated with a first quantity of bandwidth and a second channel associated with a second quantity of bandwidth. The first quantity of bandwidth may be different from the second quantity of bandwidth. The device may repeatedly adjust the transmitter signal to align the set of transmitter channel wavelengths based on a set of observed responses to the set of tones, generated based on the transmitter signal passing through an optical filter, failing to match a set of expected responses.
    Type: Grant
    Filed: October 15, 2014
    Date of Patent: January 3, 2017
    Assignee: Infinera Corporation
    Inventors: Jeffrey T. Rahn, David J. Krause
  • Patent number: 9490602
    Abstract: A laser system including a pressure adjusting part adjusting the laser gas pressure in the laser gas container, a pressure control unit controlling the pressure adjusting part so that before startup of the laser oscillator, the laser gas pressure becomes a first gas pressure lower than atmospheric pressure and so that at a preparatory stage after startup of the laser oscillator and before radiation of the laser light, the laser gas pressure becomes a second gas pressure capable of oscillating laser light, a laser control unit controlling the laser oscillator so that the laser oscillator executes an initial operation, a laser detector detecting the laser light output by the initial operation, and a hermetic seal estimating part estimating an extent of hermetic seal of the laser gas container based on a detection value obtained by the laser detector.
    Type: Grant
    Filed: March 4, 2014
    Date of Patent: November 8, 2016
    Assignee: Fanuc Corporation
    Inventor: Akihiko Nishio
  • Patent number: 9448159
    Abstract: The present invention relates to a gas cell (1) for optical measurements of gas content and/or concentration comprising a cavity (1a), at least one aperture (11) for gas exchange, at least one first socket (12) for light emitting means (2) and at least one second socket (13) for light detecting means (3). The length of an optical measuring path (A) through the cavity (1a) is defined by a direct or indirect distance between a light emitting means (2) in the first socket (12) and a light detecting means (3) in the second socket (13). The present invention teaches that an epoxy mold compound is used to form at least the parts of the gas cell (1) that define the optical measuring path (A).
    Type: Grant
    Filed: November 30, 2012
    Date of Patent: September 20, 2016
    Assignee: Senseair AB
    Inventor: Hans Göran Evald Martin
  • Patent number: 9419722
    Abstract: We disclose an optical transponder, in which one or more all-electronic feedback paths are used to obtain a relatively accurate estimate of the device-specific signal distortions in the transmitter portion thereof. The obtained estimate is used to enable the digital signal processor of the optical transponder to carry out electronic pre-distortion (EPD) that can significantly reduce or cancel these signal distortions without the use of detailed factory-calibration measurements or optics dedicated to feedback purposes. The use of all-electronic feedback paths may enable a beneficial reduction in the cost of the EPD functionality, e.g., by eliminating a significant extra cost associated with the implementation of optically generated feedback.
    Type: Grant
    Filed: August 27, 2014
    Date of Patent: August 16, 2016
    Assignee: Alcatel Lucent
    Inventors: Peter J. Winzer, Andrew Adamiecki, Chandrasekhar Sethumadhavan, Gregory Raybon
  • Patent number: 9413138
    Abstract: A method of controlling a wavelength tunable laser to control an oscillation wavelength based on a difference between a detection result of a wavelength by a wavelength detecting unit and a target value, the method includes: acquiring a first drive condition of the wavelength tunable laser to make the wavelength tunable laser oscillate at a first wavelength from a memory; calculating a second drive condition to drive the wavelength tunable laser at a second wavelength by referring to the first drive condition and a wavelength difference between the first wavelength and the second wavelength, the second wavelength differing from the first wavelength; and driving the wavelength tunable laser based on the second drive condition calculated at the calculating of the second drive condition.
    Type: Grant
    Filed: July 31, 2013
    Date of Patent: August 9, 2016
    Assignee: SUMITOMO ELECTRIC DEVICE INNOVATIONS, INC.
    Inventors: Hirokazu Tanaka, Masao Shibata, Hiromitsu Kawamura, Mitsuyoshi Miyata
  • Patent number: 9395487
    Abstract: Provided are an optical element and a wavelength monitor capable of detecting a wavelength with high accuracy and at high speed while suppressing a size. The optical element includes: a branch waveguide section configured to branch an input light beam and generate two outputs routed via paths having mutually different optical path lengths; and an optical synthesis section configured to synthesize the two outputs and output two optical signals having different light intensities with regards to a wavelength of the input light beam and exhibiting a mutual phase difference.
    Type: Grant
    Filed: September 23, 2014
    Date of Patent: July 19, 2016
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Katsumi Uesaka, Yutaka Onishi
  • Patent number: 9389080
    Abstract: A ring laser gyroscope comprises a laser block that defines an optical closed loop pathway configured to contain a lasing gas. A plurality of mirror structures are respectively mounted on the laser block, with each of the mirror structures having a respective reflective surface that is in optical communication with the optical closed loop pathway. A plurality of electrodes are coupled to the laser block, with the electrodes configured to generate a pair of counter-propagating laser beams from the lasing gas in the optical closed loop pathway. At least one optical sensor is coupled to one of the mirror structures, with the optical sensor in optical communication with the closed loop pathway. A polarizer is in optical communication with the optical sensor. The polarizer is configured to pass laser light having substantially one polarization mode to the optical sensor.
    Type: Grant
    Filed: January 8, 2014
    Date of Patent: July 12, 2016
    Assignee: Honeywell International Inc.
    Inventors: Christina Marie Schober, Bruce A. Seiber, Rodney Harold Thorland, James A. Vescera
  • Patent number: 9343869
    Abstract: Described herein are methods, systems, and apparatuses to utilize a laser device comprising a gain section, a wavelength filter, a first reflector, and a second reflector to form a laser cavity with the first reflector, the laser cavity to include the gain section and the wavelength filter. The wavelength filter is temperature stabilized to a predetermined temperature range and the remaining portions of the laser cavity are not temperature stabilized. The wavelength filter, when at the predetermined temperature range, comprises a plurality of adjacent longitudinal modes such that a difference in modal gain values associated with each of the adjacent longitudinal modes is within a predetermined delta. Thus, the cavity of the laser device is designed to experience some mode hops when the device temperature changes; however, because the wavelength filter is stabilized in temperature, the cavity drift due to these mode hops is within a limited range.
    Type: Grant
    Filed: August 20, 2015
    Date of Patent: May 17, 2016
    Assignee: Aurrion, Inc.
    Inventors: Erik Norberg, Brian R. Koch, Gregory Alan Fish
  • Patent number: 9276374
    Abstract: To achieve stable multimode output even when driven by a drive current near a threshold value, provided is a laser apparatus comprising a semiconductor laser element; a wavelength selecting element that performs laser oscillation by forming a resonator between itself and a reflective surface of the semiconductor laser element to output oscillated laser light; and an optical system that is optically coupled to an emission surface of the semiconductor laser element with a coupling efficiency ? and inputs to the wavelength selecting element light output from the emission surface. The optical system causes a value that is correlated with a minimum light output within a linear light output region in which light output is linear with respect to an injection current injected to the semiconductor laser element to be less than this value occurring when the coupling efficiency ? is at a maximum.
    Type: Grant
    Filed: November 13, 2013
    Date of Patent: March 1, 2016
    Assignee: Furukawa Electric Co., Ltd.
    Inventors: Hidehiro Taniguchi, Yutaka Ohki
  • Patent number: 9246302
    Abstract: Embodiments of an ultra-stable frequency reference generating system and methods for generating an ultra-stable frequency reference using a two-photon Rubidium transition are generally described herein. In some embodiments, a cavity-stabilized reference laser comprising a laser source is locked to a stabilized cavity. A Rubidium cell is interrogated by a stabilized laser output to cause at least a two-photon Rubidium transition and a detector may detect fluorescence resulting from spontaneous decay of the upper state Rubidium transition. The output of the detector is provided at a wavelength of the fluorescence to lock the cavity-stabilized reference laser to generate a stabilized laser output. A frequency comb stabilizer may be locked to the stabilized laser output to generate a super-continuum of optical wavelengths for use in generating an ultra-stable frequency reference.
    Type: Grant
    Filed: July 14, 2014
    Date of Patent: January 26, 2016
    Assignee: Raytheon Company
    Inventors: Steven R. Wilkinson, Todd O. Clatterbuck, Matthew T. Cashen, Gabriel N. Price, Jeffrey L. Sabala
  • Patent number: 9246622
    Abstract: A semiconductor optical element and an optical module in which extinction ratio variation among integrated optical modulation elements is reduced. An optical module has a wavelength multiplexer that multiplexes light respectively emerging from electric-field-absorption modulator (EAM) portions of integrated optical modulation elements, and that outputs the multiplexed light. The integrated optical modulation element has a signal input terminal, a laser element portion, and an EAM portion. Each of the integrated optical modulation elements has a difference between an oscillation wavelength and a barrier layer bandgap wavelength, represented as an LDBG wavelength difference. Variation of the LDBG wavelength differences is limited within a range of ±1 nm.
    Type: Grant
    Filed: May 1, 2014
    Date of Patent: January 26, 2016
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Asami Uchiyama, Koichi Akiyama, Yusuke Azuma, Yoshimichi Morita, Takeshi Yamatoya
  • Patent number: 9239431
    Abstract: A passively athermal photonic system including a photonic circuit having a substrate and an optical cavity defined on the substrate, and passive temperature-responsive provisions for inducing strain in the optical cavity of the photonic circuit to compensate for a thermo-optic effect resulting from a temperature change in the optical cavity of the photonic circuit. Also disclosed is a method of passively compensating for a temperature dependent thermo-optic effect resulting on an optical cavity of a photonic circuit including the step of passively inducing strain in the optical cavity as a function of a temperature change of the optical cavity thereby producing an elasto-optic effect in the optical cavity to compensate for the thermo-optic effect resulting on an optical cavity due to the temperature change.
    Type: Grant
    Filed: November 29, 2011
    Date of Patent: January 19, 2016
    Assignee: Sandia Corporation
    Inventors: Peter T. Rakich, Gregory N. Nielson, Anthony L. Lentine
  • Patent number: 9203212
    Abstract: A semiconductor laser module includes: a semiconductor laser element having at least one semiconductor laser; a first support member on which the semiconductor laser element is mounted; a first temperature-adjusting element adjusting a temperature of the first support member; a semiconductor optical element having a semiconductor optical amplifier amplifying a laser light outputted from the semiconductor laser element; and a second support member on which the semiconductor optical element is mounted.
    Type: Grant
    Filed: November 24, 2014
    Date of Patent: December 1, 2015
    Assignee: FURUKAWA ELECTRIC CO., LTD.
    Inventors: Tatsuro Kurobe, Tatsuya Kimoto, Hideaki Hasegawa
  • Patent number: 9198580
    Abstract: An object of the present invention is to provide a noninvasive constituent concentration measuring apparatus and constituent concentration measuring apparatus controlling method, in which accurate measurement can be performed by superimposing two photoacoustic signals having the same frequency and reverse phases to nullify the effect from the other constituent occupying large part of the object to be measured. The constituent concentration measuring apparatus according to the invention includes light generating means for generating two light beams having different wavelengths, modulation means for electrically intensity-modulating each of the two light beams having different wavelengths using signals having the same frequency and reverse phases, light outgoing means for outputting the two intensity-modulated light beams having different wavelengths toward a test subject, and acoustic wave detection means for detecting an acoustic wave generated in the test subject by the outputted light.
    Type: Grant
    Filed: November 5, 2012
    Date of Patent: December 1, 2015
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Kazunori Naganuma, Takuro Tajima, Yuichi Okabe, Shoichi Sudo
  • Patent number: 9203214
    Abstract: A laser system comprising a laser configured to generate a laser beam, a power supply arranged to provide a drive power to the laser, a photodetector arranged to detect the power of the laser beam and provide a detection signal from the power of the laser beam and a feedback loop arranged to form a feedback signal by subtracting a target signal from the detection signal wherein the feedback signal has a high bandwidth, amplify the feedback signal and adjust the drive power according to the amplified feedback signal, thereby reducing noise in the laser beam.
    Type: Grant
    Filed: December 16, 2013
    Date of Patent: December 1, 2015
    Assignee: Laser Quantum Inc.
    Inventor: Alan Cox
  • Patent number: 9195113
    Abstract: An tunable optical frequency comb source includes a linear waveguide having an input leg to couple to a pump laser. A ring microresonator is evanescently coupled to the linear waveguide. The microresonator includes a ring shaped waveguide having a core material with a nonlinear refractive index to provide four-wave mixing to generate a cascade of independent laser beams at frequencies corresponding to the longitudinal modes of the microresonator.
    Type: Grant
    Filed: May 16, 2013
    Date of Patent: November 24, 2015
    Assignee: Honeywell International Inc.
    Inventor: James A. Cox
  • Patent number: 9197031
    Abstract: The invention describes a new method of tuning a Fabry-Perot resonant etalon, whose length is actively controlled through the frequency of an identical length microwave resonant cavity. The length is tunable over a several micron range with the precision and stability of the microwave source frequency.
    Type: Grant
    Filed: February 17, 2015
    Date of Patent: November 24, 2015
    Inventor: Karoly Holczer
  • Patent number: 9190807
    Abstract: A method for optimizing startup time and efficiency for a WBC laser diode system having numerous diode elements, wherein each diode element is measured, an optimal band region is determined for each diode element, and placed in an optimal placement within an array of diode elements.
    Type: Grant
    Filed: December 16, 2014
    Date of Patent: November 17, 2015
    Assignee: TeraDiode, Inc.
    Inventors: Parviz Tayebati, Bien Chann, Robin Huang, Bryan Lochman, Francisco Villarreal-Saucedo, James Zambuto
  • Patent number: 9184564
    Abstract: An external resonator type light emitting system includes a light source oscillating a semiconductor laser light and a grating device providing an external resonator with the light source. The light source includes an active layer oscillating the semiconductor laser light. The grating device includes an optical waveguide having an incident face to which the semiconductor laser is incident and an emitting face of emitting an emitting light of a desired wavelength, a Bragg grating formed in the optical waveguide, and a propagating portion provided between the incident face and the Bragg grating. Formulas (1) to (4) are satisfied.
    Type: Grant
    Filed: April 22, 2014
    Date of Patent: November 10, 2015
    Assignee: NGK INSULATORS, LTD.
    Inventors: Jungo Kondo, Shoichiro Yamaguchi, Takashi Yoshino, Yukihisa Takeuchi
  • Patent number: 9184552
    Abstract: A laser apparatus includes an external cavity laser (ECL) where the optical signal is modulated by an electrical modulation signal for modulating in frequency the laser output signal. The modulation in frequency produces a modulation of intensity (power) of the laser output signal, also denoted amplitude modulation (AM). A method of controlling the AM amplitude of a signal emitted by an ECL includes a gain medium, a phase element with variable transmissivity induced by the modulation, and a spectrally selective optical filter that selects and keeps the AM amplitude below a certain desired value or minimizes such value. A control method and a laser apparatus are also described in which the reduction of the AM component of the output power is achieved by acting on the gain of the gain medium of the ECL.
    Type: Grant
    Filed: July 25, 2013
    Date of Patent: November 10, 2015
    Assignee: Google Inc.
    Inventors: Paolo Baroni, De Donno Marco, Anna Ronchi
  • Patent number: 9172206
    Abstract: A laser system includes a seed laser configured to generate a plurality of optical pulses; a controller configured to receive the plurality of the optical pulses and obtain chirped pulses, each chirped pulse having a chirping amount different from each other; an optical waveguide, having a characteristic of anomalous dispersion, configured to cause soliton self-frequency shifts while the chirped pulses propagating so that each center wavelength of a pulse which output from the optical waveguide is different from each other.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: October 27, 2015
    Assignee: Canon Kabushiki Kaisha
    Inventor: Takefumi Ota
  • Patent number: 9164027
    Abstract: There is provided a frequency tunable laser system comprising a laser, frequency varying means arranged for varying an optical frequency output of the laser, an intensity sensor arranged for receiving light from the laser, and a processor arranged for controlling the frequency varying means for varying the optical frequency output of the laser and receiving an intensity signal from the intensity sensor for monitoring the intensity output of the laser. The frequency tunable laser system further comprises an external reflective surface, in use, fixedly arranged in a light path of the laser beam outside the laser cavity at a predefined distance from the second reflective surface along the light path of the laser beam to reflect part of the emitted laser beam back into the laser cavity.
    Type: Grant
    Filed: April 17, 2013
    Date of Patent: October 20, 2015
    Assignee: Nederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek TNO
    Inventors: Remco Alexander Nieuwland, Bart Michiel De Boer
  • Patent number: 9136666
    Abstract: Described herein are methods, systems, and apparatuses to utilize a laser device comprising a gain section, a wavelength filter, a first reflector, and a second reflector to form a laser cavity with the first reflector, the laser cavity to include the gain section and the wavelength filter. The wavelength filter is temperature stabilized to a predetermined temperature range and the remaining portions of the laser cavity are not temperature stabilized. The wavelength filter, when at the predetermined temperature range, comprises a plurality of adjacent longitudinal modes such that a difference in modal gain values associated with each of the adjacent longitudinal modes is within a predetermined delta. Thus, the cavity of the laser device is designed to experience some mode hops when the device temperature changes; however, because the wavelength filter is stabilized in temperature, the cavity drift due to these mode hops is within a limited range.
    Type: Grant
    Filed: February 2, 2015
    Date of Patent: September 15, 2015
    Assignee: Aurrion, Inc.
    Inventors: Erik Norberg, Brian R. Koch, Gregory Alan Fish
  • Patent number: 9083145
    Abstract: A system and method that can be employed to lock and scan the output of a laser cavity (2) is described. The system and method involves the use of a signal generator for generating an error signal between an output of the laser cavity (28) and the transmission (28) of the laser through a tunable external reference cavity (3). A dual piezo-actuated mirror (6b) permits processing of the error signal (26) with separate signal processing circuits (29a, 29b) used to provide an electrical feedback signal to the two piezo-electric crystals (22, 23b). When incorporated within a laser cavity the described system and methodology can be used to lock and scan the output of the laser cavity while providing the laser output with a reduced linewidth.
    Type: Grant
    Filed: May 22, 2013
    Date of Patent: July 14, 2015
    Assignee: M SQUARED LASERS LIMITED
    Inventor: William Miller
  • Patent number: 9060691
    Abstract: An object of the present invention is to provide a noninvasive constituent concentration measuring apparatus and constituent concentration measuring apparatus controlling method, in which accurate measurement can be performed by superimposing two photoacoustic signals having the same frequency and reverse phases to nullify the effect from the other constituent occupying large part of the object to be measured. The constituent concentration measuring apparatus according to the invention includes light generating means for generating two light beams having different wavelengths, modulation means for electrically intensity-modulating each of the two light beams having different wavelengths using signals having the same frequency and reverse phases, light outgoing means for outputting the two intensity-modulated light beams having different wavelengths toward a test subject, and acoustic wave detection means for detecting an acoustic wave generated in the test subject by the outputted light.
    Type: Grant
    Filed: November 5, 2012
    Date of Patent: June 23, 2015
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Kazunori Naganuma, Takuro Tajima, Yuichi Okabe, Shoichi Sudo
  • Publication number: 20150146282
    Abstract: Wavelength-selective external resonators can be used to greatly increase the output brightness of dense wavelength beam combining (DWBC) system beams by stabilizing the wavelengths of the beams emitted by the individual emitters of the DWBC laser source. The present invention pertains to external resonant cavities that utilize thin-film filtering elements as wavelength-selective elements in external resonators. The present invention further pertains to particular embodiments that utilize thin-film filtering elements in DWBC systems as both output beam coupling elements and wavelength selective elements. The present invention provides advantages over the prior art that include decreased cost, increased fidelity of wavelength selection, and increased wall plug efficiency.
    Type: Application
    Filed: November 22, 2013
    Publication date: May 28, 2015
    Inventors: Rudolf Huber, Hagen Zimer, Alexander Killi, Christoph Tillkorn, Steffen Ried
  • Patent number: 9042415
    Abstract: A method to tune an emission wavelength of a laser diode (LD) finely is disclosed. The method first controls a temperature of the etalon filter in T1 or T2, where the transmittance of the etalon filter becomes 40 to 50%, assuming a height between the peak and the bottom of the periodic transmittance to be 100%, at the grid wavelength ?1 or ?2, respectively. Then, the temperature of the LD is adjusted such that the intensity of light emitted from the LD and transmitted through the etalon filter becomes 40 to 50%.
    Type: Grant
    Filed: June 18, 2013
    Date of Patent: May 26, 2015
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Eiichi Banno
  • Publication number: 20150131686
    Abstract: A hybrid external cavity laser and a method for configuring the laser having a stabilized wavelength is disclosed. The laser comprises a semiconductor gain section and a volume Bragg grating, wherein a laser emission from the semiconductor gain section is based on a combination of a reflectivity of a front facet of the semiconductor gain section and a reflectivity of the volume Bragg grating and the reflectivity of the semiconductor gain section and the volume Bragg grating are insufficient by themselves to support the laser emission. The hybrid cavity laser further comprises an etalon that provides further wavelength stability.
    Type: Application
    Filed: December 3, 2013
    Publication date: May 14, 2015
    Inventors: John C. Connolly, Donald E. Ackley, Scott L. Rudder, Harald R. Guenther
  • Patent number: 9005261
    Abstract: A therapeutic laser with a source of pulsed electromagnetic radiation, a control device for controlling the intensity and/or the duration of the therapeutic laser applied to the tissue, and a detection device for detecting optoacoustic signals triggered by irradiating the living tissue with the pulsed electromagnetic radiation. The therapeutic laser is characterized by an evaluation device that acts on the control device and is used for calculating a degree of quality B(t) from the optoacoustic signals detected by the detection device for individual laser pulses applied to a predetermined laser spot and determining a fit function f(t) at a predetermined point in time ?t1, the fit function f(t) approximating the mean curve of B(t) for 0?t??t1. The intensity and/or the irradiation time of the therapeutic laser is defined by the parameters for the predetermined laser spot, the parameters being determined for the fit function f(t).
    Type: Grant
    Filed: October 24, 2008
    Date of Patent: April 14, 2015
    Assignee: Medizinisches Laserzentrum Luebech GmbH
    Inventor: Ralf Brinkmann
  • Publication number: 20150092801
    Abstract: A method of controlling beam quality and stability of a laser apparatus, the laser apparatus comprising, a diode laser (10) providing first radiation of at least a first wavelength, and a frequency conversion unit (12) configured to frequency-convert the first radiation from the diode laser and to output the frequency-converted radiation (213), the frequency-converted radiation having at least a second wavelength different from the first wavelength, the diode laser (10) comprising at least a first and a second section (222,223), a first contact (220) for injecting a first current (I1) into the first section (222), a second contact (221) for injecting a second current (I2) into the second section (223), and means for controlling a temperature of the diode laser; wherein the method comprises monitoring a first parameter indicative of the power content of a dominant lobe of the first radiation; iteratively determining a combination of respective values of the first current, the second current and the temperature
    Type: Application
    Filed: March 13, 2012
    Publication date: April 2, 2015
    Inventors: Ole Bjarlin Jensen, Peter Eskil Andersen, Paul Michael Petersen, André Müller
  • Patent number: 8995482
    Abstract: A high energy semiconductor laser capable of high optical efficiency includes a master oscillator coupled to a plurality of slave oscillators, each producing a laser beam that is substantially at the same wavelength as the output beam from the master oscillator. The outputs of the slave oscillators are then coherently combined to a single monochromatic beam having an optical power which is substantially greater than that of beam output from the master oscillator. The slave oscillators can be configured as ring resonators. A suitable ring oscillator can be built by arranging one or more semiconductor diode laser gain media, two or more reflecting mirrors, and at least one semireflective mirror in a ring configuration. A suitable ring oscillator can also be built by machining a solid block to include one or more semiconductor diode laser high gain regions.
    Type: Grant
    Filed: November 3, 2010
    Date of Patent: March 31, 2015
    Inventors: Peter Moshchansky-Livingston, Richard A. Hutchin
  • Patent number: 8982450
    Abstract: Feedback loops can be used to shift and stabilize the carrier-envelope phase of a frequency comb from a mode-locked fibers laser or other optical source. Compared to other frequency shifting and stabilization techniques, feedback-based techniques provide a wideband closed-loop servo bandwidth without optical filtering, beam pointing errors, or group velocity dispersion. It also enables phase locking to a stable reference, such as a Ti:Sapphire laser, continuous-wave microwave or optical source, or self-referencing interferometer, e.g., to within 200 mrad rms from DC to 5 MHz. In addition, stabilized frequency combs can be coherently combined with other stable signals, including other stabilized frequency combs, to synthesize optical pulse trains with pulse durations of as little as a single optical cycle. Such a coherent combination can be achieved via orthogonal control, using balanced optical cross-correlation for timing stabilization and balanced homodyne detection for phase stabilization.
    Type: Grant
    Filed: March 4, 2014
    Date of Patent: March 17, 2015
    Assignee: Massachusetts Institute of Technology
    Inventors: Jonathan A. Cox, Franz X. Kaertner