Feedback Circuitry Patents (Class 372/29.011)
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Patent number: 7843977Abstract: 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: GrantFiled: June 19, 2008Date of Patent: November 30, 2010Assignee: Agilent Technologies, Inc.Inventors: Eric Stephen Johnstone, Miao Zhu, Tirumala R. Ranganath
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Patent number: 7839906Abstract: 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: GrantFiled: June 6, 2007Date of Patent: November 23, 2010Assignee: Marvell International Ltd.Inventors: Pantas Sutardja, Christopher Painter
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Publication number: 20100272127Abstract: 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: ApplicationFiled: April 23, 2009Publication date: October 28, 2010Inventors: Tony Lam, ChenChun Wu
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Publication number: 20100272135Abstract: 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: ApplicationFiled: April 28, 2009Publication date: October 28, 2010Inventors: Dmitri Vladislavovich Kuksenkov, Shenping Li
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Patent number: 7822084Abstract: 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: GrantFiled: April 9, 2008Date of Patent: October 26, 2010Assignee: Cymer, Inc.Inventors: Kevin M. O'Brien, Robert N. Jacques
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Patent number: 7822096Abstract: 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: GrantFiled: December 12, 2008Date of Patent: October 26, 2010Assignee: Corning IncorporatedInventor: Dmitri Vladislavovich Kuksenkov
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Publication number: 20100265974Abstract: 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: ApplicationFiled: April 20, 2009Publication date: October 21, 2010Applicant: EMCORE CORPORATIONInventor: William Wang
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Patent number: 7809034Abstract: 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: GrantFiled: February 14, 2008Date of Patent: October 5, 2010Assignee: Sumitomo Electric Industries, Ltd.Inventor: Keiji Tanaka
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Publication number: 20100246613Abstract: A semiconductor laser is provided capable of generating very narrow laser beams and having stable characteristics, a method for generating the laser beams and a method for reducing a spectral line-width of the laser beams. The semiconductor laser includes a semiconductor active layer, a photonic crystal optical waveguide forming a periodic structure of two-dimensional refractive index within a plane perpendicular to a semiconductor laminate direction directly or indirectly connected to the semiconductor active layer; and an optical cavity that contains the semiconductor active layer and the photonic crystal optical waveguide and oscillates light that is generated from the semiconductor active layer and is guided through the photonic crystal optical waveguide as laser.Type: ApplicationFiled: January 19, 2010Publication date: September 30, 2010Applicant: FURUKAWA ELECTRIC CO., LTD.Inventor: Hideaki Hasegawa
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Publication number: 20100246614Abstract: There is provided a wavelength variable light source system capable of changing wavelength and intensity of output signal light and of improving preset accuracy and stability of the wavelength and strength of the output signal light. The system determines the both or either one of a target value for controlling wavelength and a target value for controlling intensity of output signal light of a wavelength variable light source by correlating a combination of the target wavelength and the target light output intensity specified from a higher-level device and controls operation states of the wavelength variable light source so that output values of monitoring circuit s for monitoring the operation state of the wavelength variable light source converge to the target values.Type: ApplicationFiled: March 26, 2010Publication date: September 30, 2010Applicant: FURUKAWA ELECTRIC CO., LTD.Inventors: Hiroyuki Koshi, Koji Horikawa
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Patent number: 7801189Abstract: Examples and implementations of photonic devices and techniques based on whispering gallery mode resonators formed of electro-optic materials to effectuate cross modulation between whispering gallery modes of different polarizations in the resonators.Type: GrantFiled: November 13, 2008Date of Patent: September 21, 2010Assignee: OEWaves, Inc.Inventors: Lutfollah Maleki, Andrey B. Matsko, Anatoliy Savchenkov, Vladimir Ilchenko
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Patent number: 7782915Abstract: The present invention is to provide alight emitting module that improves the positional precision of a semiconductor laser diode. A light emitting module of the present invention is configured with a semiconductor laser diode having a facet which inputs, or outputs light; an integrated circuit which is electrically connected to the semiconductor laser diode; and a package which mounts the semiconductor laser diode and the integrated circuit therein. The semiconductor laser diode is mounted on the integrated circuit, and the integrated circuit has a marker. The marker is utilized in determining a position of the semiconductor laser diode with respect to the integrated circuit, and further in determining a position of the semiconductor laser diode with respect to the package.Type: GrantFiled: August 22, 2006Date of Patent: August 24, 2010Assignee: Sumitomo Electric Industries Ltd.Inventor: Akihiro Moto
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Patent number: 7777940Abstract: Methods and systems for optical chirped pulse amplification and phase dispersion, the system including an active dispersion controller for receiving an input optical pulse from a modelocked laser and controlling a third and fourth order dispersion property of the input optical pulse to produce an optical output pulses, a stretching re-circulating loop for stretching the optical output pulses in time, an optical amplifier for amplifying the stretched optical output pulses, a compressing re-circulating loop for compressing the amplified stretched optical output pulse to produce a compressed optical output pulse, and a feedback loop for feeding a feedback optical signal to the active dispersion controller.Type: GrantFiled: February 8, 2008Date of Patent: August 17, 2010Assignee: University of Central Florida Research Foundation, Inc.Inventors: Peter J. Delfyett, Scott Rozzo
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Patent number: 7773652Abstract: In a gain-coupled distributed feedback semiconductor laser, a coating of a low reflectivity is provided on a front facet from which laser light is emitted and a coating of a high reflectivity is provided on a rear facet, thus forming asymmetric coatings. The semiconductor laser has a structure in which an absorption diffraction grating is located along an optical waveguide, and the diffraction grating includes a phase shift region.Type: GrantFiled: June 27, 2006Date of Patent: August 10, 2010Assignee: Mitsubishi Electric CorporationInventors: Kazuhisa Takagi, Keisuke Matsumoto
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Publication number: 20100195682Abstract: Jitter and waveform are improved by reducing the wavelength spectrum width of a laser beam pulse. In a laser pulse generating apparatus according to the present invention, a semiconductor laser device, a polarization maintaining optical fiber, an optical reflection filter having bandpass characteristics using an FBG whose passband can be changed by changing a tension, and an optical isolator are connected via an optical fiber. A driving circuit drives the semiconductor laser device to generate a pulse. The optical reflection filter performs filtering by transmitting a specific component of the wavelength spectrum of the pulse, reflects a portion of the optical power, and outputs the remaining optical power except the reflected portion to the outside via the optical isolator. The reflected pulse is fed back to the semiconductor laser device to thereby reduce the wavelength spectrum width of the laser beam, and improve the jitter and waveform.Type: ApplicationFiled: June 16, 2008Publication date: August 5, 2010Inventor: Koji Nonaka
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Patent number: 7760779Abstract: The laser drive circuit of the present invention includes a first drive circuit 105 receiving an input of a current from a variable current source 103 and a first pulse control signal 101 and outputting a first drive current in synchronism with the first pulse control signal 101; a pulse output circuit 107 outputting a pulse signal in response to a falling edge of the first pulse control signal 101; and a second drive circuit 106 receiving an input of a current from a variable current source 104 and a second pulse control signal 102, generating a second drive current in synchronism with the second pulse control signal 102, and outputting a decreased current value of the second drive current at least in synchronism with the pulse signal. According to this configuration, the falling time of the pulse can be shortened regardless of the relationship between the voltage of a laser connecting terminal and the power source voltage of a drive circuit or a ground voltage.Type: GrantFiled: April 5, 2007Date of Patent: July 20, 2010Assignee: Panasonic CorporationInventor: Haruhiko Mizuno
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Publication number: 20100158055Abstract: A method of monitoring the output power of a laser diode in a barcode reader. The method includes sampling a threshold monitoring-current that is related the driving-current passing through the laser diode during a first time period when this current is at the lasing threshold of the laser diode. The method includes generating a threshold-compensated monitoring-current by subtracting the threshold monitoring-current from the above-threshold monitoring-current. The method includes monitoring the output power of the laser diode in the barcode reader at least partially based on the threshold-compensated monitoring-current.Type: ApplicationFiled: December 18, 2008Publication date: June 24, 2010Applicant: SYMBOL TECHNOLOGIES, INC.Inventor: James Giebel
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Publication number: 20100150189Abstract: 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: ApplicationFiled: November 25, 2009Publication date: June 17, 2010Applicant: SONY DISC & DIGITAL SOLUTIONS INC.Inventors: Kunio Nakayama, Koji Ishiwata, Cheonseok Park
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Publication number: 20100135346Abstract: The present invention provides a system and method for creating a coherent optical comb comprising a plurality of lasers, each laser providing an optical output channel; means for combining each optical channel output; a modulator for modulating the combined optical channel outputs, to provide a modulated signal; means for feeding back said modulated signal to said plurality of lasers, such that each laser output channel is phase and/or frequency locked with respect to at least one other of said plurality of lasers. A discrete optical comb is obtained without the need for excessively high power laser outputs and only employs a single (optional) wavelength locker for all channels.Type: ApplicationFiled: October 6, 2009Publication date: June 3, 2010Applicant: University College CorkInventors: Frank Peters, Andrew Ellis
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Patent number: 7725043Abstract: A laser transmitter with a feedback control loop for minimizing noise. The novel laser transmitter includes a laser, an external reflector adapted to form an extended cavity to the laser, and a feedback control loop adapted to detect noise in the laser and in accordance therewith, adjust the optical phase of the extended cavity such that the noise is at a desired level. The optical phase of the extended cavity is adjusted by adjusting an operating parameter of the laser, such as its bias current. In an illustrative embodiment, the feedback control loop is adapted to compute the rate of change of the noise with respect to bias current and in accordance therewith, adjust the bias current of the laser such that relative intensity noise and interferometric intermodulation distortion are simultaneously minimized.Type: GrantFiled: October 7, 2004Date of Patent: May 25, 2010Assignee: Raytheon CompanyInventors: Willie W. Ng, David L. Persechini, Robert H. Buckley
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Patent number: 7711021Abstract: The present invention provides a laser diode driving circuit able to reduce the degradation of the optical output from the laser diode even when the characteristic of the laser diode widely scatters. The circuit provides a filter circuit connected in parallel to the laser diode that compensates the frequency dependence of the laser diode. In the invention, the frequency characteristic of this filter circuit may be varied depending on the scattering in the frequency response of the laser diode, or on the temperature characteristic of the diode.Type: GrantFiled: May 31, 2007Date of Patent: May 4, 2010Assignee: Sumitomo Electric Industries Ltd.Inventor: Naoki Nishiyama
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Patent number: 7711018Abstract: The luminance of a laser diode is a function of laser diode drive current. The luminance is also a function of other factors, such as age and temperature. A laser projection device includes laser diodes to generate light in response to a commanded luminance, and also includes photodiodes to provide a measured luminance. The commanded luminance and measured luminance are compared, and drive currents for the laser diodes are adjusted to compensate for changes in laser diode characteristics.Type: GrantFiled: December 21, 2007Date of Patent: May 4, 2010Assignee: Microvision, Inc.Inventors: Mark Champion, Heng Huang
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Publication number: 20100091806Abstract: A method for improving spectral, spatial, and temporal stability of semiconductor lasers and their beam profile uniformity based on statistical average of plural transient or unsteady state longitudinal and lateral modes that are continuously perturbed. A laser module implementing the method comprises a semiconductor laser, a drive circuit generating RF-modulated drive current, and an automatic power control loop for producing stable, low noise and uniform or nearly uniform illumination field along one or two dimensions.Type: ApplicationFiled: October 10, 2008Publication date: April 15, 2010Applicant: Pavilion Integration CorporationInventors: Ningyi Luo, Sheng-Bai Zhu, Hui Fan, Jindong Li
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Patent number: 7697580Abstract: A power monitoring and correction to a desired power level of a laser or group of lasers utilizes two photodetectors which are employed to accurately determine the amount of output power from the front end or “customer” end of a laser or a plurality of such lasers. During power detection, which may be accomplished intermittently or continuously, the laser is modulated with a tone of low frequency modulation. One photodetector at the rear of the laser is employed to detect the DC value of the frequency tone, i.e., a value or number representative of the AC peak-to-peak swing, amplitude or modulation depth of the tone. Also, the rear photodetector may be employed to determine the optical modulation index (OMI). In either case, these values may be employed in a closed loop feedback system to adjust or otherwise calibrate the value of the low tone frequency relative to the total desired bias current applied to the laser.Type: GrantFiled: October 8, 2004Date of Patent: April 13, 2010Assignee: Infinera CorporationInventors: Robert W. Smith, Alan C. Nilsson
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Patent number: 7697579Abstract: Methods and devices for a coupled optoelectronic oscillator having optical frequency stabilization. The coupled optoelectronic oscillator includes a harmonically mode-locked laser cavity having a Mach-Zehnder modulator for mode-locking and an intracavity Fabry-Perot etalon to allow only one single supermode to lase, a stabilization loop coupled with the Fabry-Perot etalon to detect changes in the laser cavity optical frequency and generate an error signal to compensate for the frequency change to stabilize the mode-locking of the laser frequency stabilization, and an electrical loop between the laser cavity and the stabilization loop for driving the Mach-Zehnder modulator with the coupled optoelectronic oscillator signal.Type: GrantFiled: December 12, 2007Date of Patent: April 13, 2010Assignee: University of Central Florida Research Foundation, Inc.Inventors: Peter J. Delfyett, Franklyn Quinlan, Sangyoun Gee, Sarper Ozharar
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Patent number: 7692502Abstract: The invention relates to a method for controlling an oscillatory system with the aid of at least one measured variable by the detection of at least one oscillation component (Sx(t)) over time (t) in the form of at least one measured variable. According to said method a control variable (?u) for controlling the oscillatory system is determined from the sum of the weighted differences of the delayed oscillation component, which has been delayed at least twice by different delay times (?1>O, ?2>0) if there is one measured variable and the respective non-delayed oscillation component and if there are several measured variables the sum of the weighted differences of the delayed oscillation components (Si(t??i)), which have been respectively delayed at least once by a specific delay time (?i>0) and their respective non-delayed oscillation components (Si(t)) according to the relationship ?u=a1S1(t) b1S1(t??1)+ . . . +anSn(t)?bnSn(t??n), wherein a1, . . . , an and b1, . . .Type: GrantFiled: June 8, 2005Date of Patent: April 6, 2010Assignee: Georg-August-Universitat GottingenInventors: Ulrich Parlitz, Alexander Ahlborn
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Publication number: 20100054288Abstract: The present invention relates to a method and device for reducing the phase noise of a laser signal from a laser source. This device comprises a first current generator for supplying a driving current to the laser source in view of producing the laser signal. A phase noise detector is responsive to the laser wavelength for generating a phase error signal and a second current generator is responsive to the phase error signal for generating a compensation current added to the driving current supplied to the laser source for generating a phase-adjusted laser signal. The device therefore defines a phase stabilization loop formed by the phase noise detector and the second current generator, for reducing the phase noise of the laser signal.Type: ApplicationFiled: October 12, 2006Publication date: March 4, 2010Applicant: Sensilaser Technologies Inc.Inventor: Qing He
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Patent number: 7672345Abstract: A drive signal for driving a semiconductor laser is generated on the basis of an image signal inputted in synchronism with a pixel clock. A bias signal to the semiconductor laser is generated at a timing earlier than the drive signal by a predetermined time. The bias signal is disabled in synchronism with the leading edge of the drive signal.Type: GrantFiled: January 20, 2009Date of Patent: March 2, 2010Assignee: Canon Kabushiki KaishaInventor: Tsuyoshi Moriyama
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Patent number: 7656037Abstract: An integrated circuit arrangement is disclosed. In one embodiment, the integrated circuit arrangement includes at least three conductive structures levels and elongated interconnects.Type: GrantFiled: September 21, 2006Date of Patent: February 2, 2010Assignee: Infineon Technologies AGInventors: Martina Hommel, Heinrich Koerner, Markus Schwerd, Martin Seck
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Patent number: 7653103Abstract: A pulse oscillating type solid laser unit that has a laser unit body whose exciting source is a laser diode that emits light in a principal energy absorbing spectrum of a solid laser activated media, and characterized by that prior to radiating laser light outside the laser unit body as a calibrating operation of a pulse laser output value, specified several varieties of rectangle pulse current values are conducted to a laser diode inside the pulse oscillating type solid laser unit so as to pulse-oscillate the laser unit body, a mean laser output value in each rectangle pulse current value is measured by the use of a laser output measuring instrument arranged inside the laser unit body so as to obtain a mean laser output value data, and in case that the laser output light is radiated outside the laser unit body, a pulse current value linear-predicted based on an obtained mean output value data is conducted to the laser diode so as to obtain a desired pulse laser output value.Type: GrantFiled: April 19, 2007Date of Patent: January 26, 2010Assignee: Kataoka CorporationInventor: Nobuaki Iehisa
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Patent number: 7653101Abstract: A semiconductor laser light emitting circuit includes a semiconductor laser diode emitting a laser light by modulating a current supplied thereto, a light intensity detection circuit that detects the laser light and generates a voltage, and a voltage-current conversion circuit converting a voltage into a current supplied to the laser diode. A S/H capacitance is provided to store electric charge and output a voltage to the voltage/current conversion circuit. A first operational amplifier is provided to output a first current charging the S/H capacitance. A rapidly charging circuit is provided to charge the S/H capacitance with a second current. The rapidly charging circuit terminates charging when the voltage is equal to or more than a second reference voltage.Type: GrantFiled: March 3, 2008Date of Patent: January 26, 2010Assignee: Ricoh Company, Ltd.Inventors: Junichi Ikeda, Hiroaki Kyougoku
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Patent number: 7653102Abstract: High-speed measurements of the output power level of a laser are obtained by using a high-speed laser output power monitoring device that is capable of producing an electrical feedback signal having an amplitude that varies as the output power level of the laser varies. A high-speed amplitude detector receives the electrical feedback signal and detects the amplitude of the feedback signal and produces an optical modulation amplitude (OMA) detection signal. The OMA detection signal is received in a high-speed amplitude measurement device that measures the OMA and produces an OMA measurement value. The OMA measurement value is then processed by the laser controller to obtain a modulation current control signal, which is then output to the laser driver to cause the laser driver to adjust the laser modulation current to obtain a desired or optimum laser output power level.Type: GrantFiled: January 25, 2007Date of Patent: January 26, 2010Assignee: Avago Technologies Fiber IP (Singapore) Pte. Ltd.Inventor: Frederick W. Miller
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Patent number: 7649919Abstract: An automatic power control (APC) circuit applicable to controlling a laser generation module including a laser generator for generating laser and a photosensor for outputting a detection result corresponding to the power of the laser, includes: a comparator, coupled to the photosensor and biased by a first voltage level, for comparing the detection result and a reference signal to generate a comparison result; a level shifter, coupled the comparator, for shifting an intermediate voltage level controlled by the comparison result to generate a control voltage; and a driver, coupled to the level shifter and the laser generator, for driving the laser generator according to the control voltage and a second voltage level.Type: GrantFiled: May 26, 2006Date of Patent: January 19, 2010Assignee: MediaTek Inc.Inventor: Chien-Ming Chen
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Patent number: 7649917Abstract: The invention relates to a method and system for providing a set of continuous tuning regions from a discontinuously tuned laser, by providing a wavelength reference having at least first and second resonance peaks, sweeping the laser across a pre-determined wavelength range of the wavelength reference, and defining, within the laser sweep, one or more regions of continuous tuning operation of the laser, each of the regions corresponding to a response of the laser between adjacent resonance peaks of the wavelength reference. The advantage of the invention is that it provides a way for stitching together continuous regions of a multi-section tunable laser in an efficient and accurate manner.Type: GrantFiled: April 14, 2004Date of Patent: January 19, 2010Assignee: Intune Technologies LimitedInventors: Tommy Mullane, David McDonald, Thomas Farrell, Ciaran Polley, Peter B. O'Connor
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Patent number: 7643522Abstract: A gas discharge laser system bandwidth control mechanism and method of operation for controlling bandwidth in a laser output light pulse generated in the gas discharge laser system is disclosed which may comprise a bandwidth controller which may comprise an active bandwidth adjustment mechanism; a controller actively controlling the active bandwidth adjustment mechanism utilizing an algorithm implementing bandwidth thermal transient correction based upon a model of the impact of laser system operation on the wavefront of the laser light pulse being generated and line narrowed in the laser system as it is incident on the bandwidth adjustment mechanism. The controller algorithm may comprises a function of the power deposition history in at least a portion of an optical train of the gas discharge laser system, e.g., a linear function, e.g., a combination of a plurality of decay functions each comprising a respective decay time constant and a respective coefficient.Type: GrantFiled: October 20, 2005Date of Patent: January 5, 2010Assignee: Cymer, Inc.Inventors: Fedor B. Trintchouk, Robert N. Jacques
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Patent number: 7643525Abstract: A laser driver comprises a plurality of current sources, including at least one bias current source and at least two drive current sources. To control the laser driver, a set of operating states is defined where each operating state corresponds to a desired laser output power level and a ratio is defined that establishes a relationship between a first desired laser output and a second desired laser output. A calibration operation samples laser output power of the laser source for less than all of the operating states, computes adjustments to the current levels of the current sources based at least in part upon the ratio such that sampled laser power levels converge towards their corresponding desired laser output level. The current sources are adjusted to their corresponding computed current levels.Type: GrantFiled: October 31, 2007Date of Patent: January 5, 2010Assignee: Lexmark International, Inc.Inventors: Philip Jerome Heink, Daniel Richard Klemer, Stanley Coy Tungate, Jr., Eric Wayne Westerfield
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Patent number: 7630426Abstract: A wavelength detector detecting a change of a wavelength of a laser light with high accuracy, such that the wavelength detector includes a diffraction grating diffracting a laser light, photodetectors positioned symmetrically with respect to a 0-order diffracted light diffracted by the diffraction grating, and respective light incidence surfaces of the photodetectors that have a same shape and that are divided into a plurality of areas. The wavelength detector detects the change of the wavelength based on a value obtained by dividing a difference between (i) a sum of light intensities measured by all of the plurality of divided areas of a first photodetector and (ii) a sum of light intensities measured by all of the plurality of divided areas of a second photodetector, by a sum of light intensities measured by all of the plurality of divided areas of both photodetectors.Type: GrantFiled: March 14, 2008Date of Patent: December 8, 2009Assignee: Panasonic CorporationInventors: Kenji Nakayama, Shinichi Kadowaki
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Patent number: 7620082Abstract: A method for seeding and stabilizing an optical device, wherein the optical device includes one of a continuous wave laser, a pulsed laser, and a parametric system, the method including seeding the optical device with a seed signal, generating a feedback signal from an output of the optical device, and adjusting a wavelength of the seed signal to maintain a stable operation of the optical device based on the feedback signal. An apparatus, including an optical device having a cavity, a seed laser for generating a seed signal coupled to the optical device, a feedback generator coupled to the output of the optical device for generating a feedback signal, and means for adjusting a wavelength of the seed laser to maintain a stable operation of the optical device based on the feedback signal.Type: GrantFiled: April 30, 2007Date of Patent: November 17, 2009Assignee: The Regents of the University of CaliforniaInventor: Wytze E. van der Veer
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Patent number: 7620083Abstract: A semiconductor laser drive system and a semiconductor laser driving method where both internal noise and optical feedback noise can be simultaneously reduced are provided at low cost and low power consumption.Type: GrantFiled: August 31, 2006Date of Patent: November 17, 2009Assignee: National University Corporation Kanazawa UniversityInventor: Minoru Yamada
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Patent number: 7620081Abstract: A system for real-time linewidth reduction in an optical source includes a laser device comprising a back facet, wherein the laser device receives a modulated input current and generates an optical output signal; an etalon device disposed adjacent to the back facet of the laser device, wherein the etalon device receives an optical feedback output signal from the back facet of the laser device, and wherein the etalon device monitors the optical feedback output signal for changes in frequency and, if they exist, generates an optical correction output signal; a photo-detector device disposed adjacent to the etalon device, wherein the photo-detector device receives the optical feedback and correction output signals, and wherein the photo-detector device converts the optical feedback and correction output signals into an electrical signal; and a feedback correction loop coupled to the photo-detector device, wherein the feedback correction loop receives the electrical signal from the photo-detector device and generType: GrantFiled: September 21, 2006Date of Patent: November 17, 2009Assignee: Ciena CorporationInventor: Michael Haidar Shahine
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Publication number: 20090274471Abstract: An optical network terminal is provided for use in a passive optical network (PON). The optical network terminal includes a data port for receiving data packets from an external device and a processor for converting the data packets to data link frames. In addition, the optical network terminal includes a memory configured to store a time division multiplexing scheme identifying a time slot assigned to each of a plurality of network nodes in the PON for transmission of upstream optical signals. An optical transceiver is provided for converting the data link frames to upstream optical signals and transmitting the optical signals on an upstream TDMA (time division, multiple access) channel to an Optical Line Terminal (OLT). The optical transceiver includes a burst mode laser diode for generating the optical signals and a burst mode laser driver for biasing the laser diode with a bias signal and a modulation bias signal. The laser driver includes a dual closed loop feedback control circuit.Type: ApplicationFiled: April 30, 2008Publication date: November 5, 2009Applicant: GENERAL INSTRUMENT CORPORATIONInventors: David B. Bowler, James M. Aufiero, Francis J. Calabresi, Christopher J. Pekalsky
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Patent number: 7613216Abstract: A laser frequency stabilizing apparatus stabilizes an oscillation frequency of laser light by varying a resonator length on the basis of a saturated absorption line included in an optical output signal. The optical output signal is obtained by irradiating an absorption cell with the laser light. The laser frequency stabilizing apparatus includes: a light detecting section for detecting the optical output signal; a differential signal detecting section for detecting a differential signal of the optical light signal; an actuator for varying the resonator length; a drive section for driving the actuator; and a control section for controlling the drive section on the basis of the differential signal.Type: GrantFiled: November 30, 2007Date of Patent: November 3, 2009Assignee: Mitutoyo CorporationInventor: Hideyuki Nakagawa
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Patent number: 7608806Abstract: A method and apparatus is disclosed for optic signal power control to maintain a desired or optimum optic signal power level. During start-up, a default or target value from memory may be utilized to bias or otherwise control operation of an optic signal generator or driver. During operation, one or more parameters or aspects of the optic module or the environment may be monitored. In response to the monitoring one or more control signal may be generated to created to modify bias level, modulation level, or both. The monitoring may monitor the optic signal itself. The bias level and modulation level may be changed simultaneously.Type: GrantFiled: May 20, 2005Date of Patent: October 27, 2009Assignee: Mindspeed Technologies, Inc.Inventors: Daniel Draper, Maurice M. Reintjes, Gilberto I. Sada, Keith R. Jones
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Patent number: 7606273Abstract: An efficient and low-noise solid-state laser is optically pumped by one or more laser diode(s) driven by RF modulated current. The solid-state laser operation is stabilized by the pump source stable in both spectrum and intensity, in conjunction with automatic power control wherein the feedback loop accurately reflects the true drift in the output power. Moreover, the pump efficiency is optimized and the optical noise is minimized by adjusting the diode operation temperature such that the pump wavelength coincides with the absorption peak of the gain medium. By internally or externally modulating the amplitude of the drive current, the pump diode(s) operate in pulsed mode with controllable shape, width, repetition rate, and pulse-to-pulse intervals, which enables essentially constant optical energy produced from each pulse of the solid-state laser in high repetition rates with variable pulse-to-pulse intervals.Type: GrantFiled: October 15, 2007Date of Patent: October 20, 2009Inventors: Sheng-Bai Zhu, Ningyi Luo, Jing Yu
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Patent number: 7602825Abstract: Techniques and devices to stabilize a passively mode-locked laser against the timing jitter by using a feedback control signal based on a signal component at a high harmonic frequency of the laser pulse repetition frequency in the laser output to control the optical path length of the laser resonator.Type: GrantFiled: September 9, 2005Date of Patent: October 13, 2009Assignee: Calmar Optcom, Inc.Inventors: Anthony Hong Lin, Jingjun Zhao
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Publication number: 20090252187Abstract: The present invention relates generally to semiconductor lasers and laser projection systems. According to one embodiment of the present invention, a projected laser image is generated utilizing an output beam of the semiconductor laser. A gain current control signal is generated by a laser feedback loop to control the gain section of the semiconductor laser. Wavelength fluctuations of the semiconductor laser are narrowed by incorporating a wavelength recovery operation in a drive current of the semiconductor laser and by initiating the wavelength recovery operations as a function of the gain current control signal or an optical intensity error signal. Additional embodiments are disclosed and claimed.Type: ApplicationFiled: December 12, 2008Publication date: October 8, 2009Inventors: Anthony Sebastian Bauco, Douglas Llewellyn Butler, Martin Hai Hu, Dragan Pikula, Daniel Ohen Ricketts
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Publication number: 20090245305Abstract: Disclosed is a laser system comprising: A laser assembly (101) comprising a plurality of emitters; first and second light feedback devices (208, 232) forming respective external cavities with the laser assembly; a dispersive device (205) for redirecting respective portions of the light from the laser assembly to the first and second feedback devices (208, 232), wherein the first feedback device (232) is adapted to reflect a feedback portion of the redirected beam back onto the dispersive device (205) and to generate the output beam (233) from an output part of the first redirected beam, —an imaging device (213) for generating an optical Fourier transform of the plurality of emitters at a Fourier plane (235). The dispersive device (205) is positioned displaced from said Fourier plane (235) by a predetermined displacement (d) in a direction along said principle axis (230).Type: ApplicationFiled: December 5, 2006Publication date: October 1, 2009Applicant: Danmarks Tekniske UniversitetInventors: Ole Bjarlin Jensen, Birgitte Thestrup Nielsen, Paul Michael Petersen
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Publication number: 20090245306Abstract: 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: ApplicationFiled: April 1, 2009Publication date: October 1, 2009Applicant: TELARIS INC.Inventor: George A. Rakuljic
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Publication number: 20090225800Abstract: The subject of the invention is a laser comprising a semiconductor active medium with a population inversion lifetime ?c and a resonant cavity with a lifetime of the photons in the cavity ?p. The cavity includes means for being longitudinally monomode and means so that ?p>?c, such as for example a very long cavity, so as to obtain a laser with a very low intrinsic noise.Type: ApplicationFiled: June 7, 2006Publication date: September 10, 2009Inventors: Mehdi Alouini, Ghaya Baili, Chantal Moronvalle, Fabien Bretenaker, Daniel Dolfi
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Publication number: 20090225801Abstract: The present invention provides a semiconductor optical element applicable to an EC-LD or an SLD, and an external cavity laser having the semiconductor optical element. The semiconductor optical element has a pair of cleavage surfaces, and comprises a semiconductor substrate 11 having a base surface and a planer structure provided on the base surface and provided with a waveguide 1G having an active layer. The waveguide 1G has an end surface with low reflectivity and another end surface with certain reflectivity.Type: ApplicationFiled: September 27, 2006Publication date: September 10, 2009Applicant: ANRITSU CORPORATIONInventors: Hiroshi Mori, Atsushi Yamada, Takahiro Samejima