Abstract: A light generation and emission system and method is disclosed. A light generator generates light from a diode at a wavelength between 300 nm and 490 nm. A light beam forming subsystem forms the light to a directional light beam, and a controller that controls and directs the directional light beam to a target. The light generator can be suitably used for aiming, target acquisition, communication, identification, scanning, surveying, tracking, ignition and weapons operation.

Abstract: A correction circuit is provided, which may reduce dullness of a light output waveform due to wavelength detuning. The correction circuit includes an RC time constant circuit. The RC time constant circuit is used to correct a waveform of a current pulse outputted from a current source, the current source driving a surface-emitting semiconductor laser in a pulsed manner, so that a pulse waveform of light output of the semiconductor laser is approximately a rectangle.

Abstract: Embodiments of the present invention provide a system for increasing an operational life of a VCSEL. The system can include control circuitry for reducing an amount of bias current at high temperatures and increasing a power of the laser at low temperatures. This control circuitry can further include at least one of a temperature sensor, a Field Programmable Gate Array, a read only memory module, and an electrically erasable programmable read only memory module (EEPROM). In alternate embodiments, the control circuitry can further include a lookup table that sets the bias current depending on a temperature of the laser. The laser can be part of an optoelectronic transceiver module which can include, by way of example and not limitation, SFP, XFP, X2, XAUI, XENPAK, XPAK, GBIC, 8G, 16G, and other optoelectronic modules.

Abstract: The existing diodes in an LED or laser diode package are used to measure the junction temperature of the LED or laser diode. The light or laser emissions of a diode are switched off by removing the operational drive current applied to the diode package. A reference current, which can be lower the operational drive current, is applied to the diode package. The resulting forward voltage of the diode is measured using a voltage measurement circuit. Using the inherent current-voltage-temperature relationship of the diode, the actual junction temperature of the diode can be determined. The resulting forward voltage can be used in a feedback loop to provide temperature regulation of the diode package, with or without determining the actual junction temperature. The measured forward voltage of a photodiode or the emissions diode in a diode package can be used to determine the junction temperature of the emissions diode.

Abstract: Embodiments of the invention provide a laser light source comprising: a plurality of lasers connected in series; and a laser driver controllable to simultaneously drive a substantially same current through a combination of the lasers selectable from different combinations of lasers in the plurality of lasers and not through lasers in the plurality of lasers that are not in the combination.

Abstract: Disclosed is a semiconductor laser driving unit that outputs a driving current for driving a semiconductor laser. A value of a correction current is set in such a manner as to determine a rising characteristic and/or a falling characteristic of an output of the driving current in accordance with a value of the driving current.

Abstract: A laser system can include a laser and a laser output modulator to modulate the output of the laser.

Abstract: A command apparatus (10) for a plurality of laser power supplies (11, 12) comprises: a command generating section (5) generating commands for the laser power supplies; and a separating section (36) separating the generated commands into a bias command, an output command, an offset command and a gain command, wherein the bias command and the output command are common to the laser power supplies, the offset command and the gain command are defined at least in accordance with the discharge tubes corresponding to the laser power supplies respectively, wherein the command apparatus further comprises a transmitting section (37) transmitting, to the laser power supplies, the bias and the output command which are common to the laser power supplies and, transmitting the offset and the gain command defined at least in accordance with the discharge tubes corresponding to the laser power supplies respectively, corresponding to the laser power supplies.

Abstract: A laser diode driving device (1) of the present invention includes: a variable DC power supply (3) for outputting a voltage for driving laser diodes (LD1 to LDn); a current driving element (4) for causing a current If to flow; a current control section (5) for controlling (i) turning on and off of the current driving element (4) and (ii) the amount of the current If; and a power supply control section (7) for controlling an output voltage of the variable DC power supply (3). The power supply control section (7) controls, on the basis of If-Vf characteristic data (D2), voltage drop characteristic data (D3), and Vds setting data (D4) all stored in a memory section (8), the output voltage of the variable DC power supply (3) so that the current driving element (4) has a constant inter-terminal voltage regardless of the amount of the current If.

Abstract: An optical device includes: a light source that emits laser beams; a detecting unit that detects the laser beams and converts light amounts of the detected laser beams into voltage values; a first storage unit that stores in advance a light amount to be output for each of the laser beams and the voltage value; a second storage unit that stores in advance a value indicating light use efficiency of an optical system that guides the laser beams to a surface to be scanned for scanning; a calculating unit that calculates a target voltage value for each of the laser beams based on the light amount and the voltage value and also on the value indicating the light use efficiency; and a control unit that controls emission power for each of the laser beams so that the voltage value output from the detecting unit approaches the target voltage value.

Abstract: A broadband quantum cascade laser (QCL) source includes one or more QCLs having an active region designed based on a diagonal laser transition. The QCL source may include multiple QCLs formed in an array or the QCL source may comprise a single QCL device. Although each QCL provides an emission spectrum comprising a small range of wavelengths at a given applied voltage, changes in the applied operating voltage result in changes in the emission spectrum of the QCL due to the Stark shift. When the QCL source comprises a plurality of QCLs formed in an array, at least some of the elements in the array may receive different applied operating voltages such that the combined output spectrum of the array is broader than that achievable by a single QCL.

Abstract: A semiconductor laser driving device and an image forming apparatus are disclosed that are capable of accurately detecting the deterioration of the semiconductor laser with a smaller circuit size and regardless of the variation of the characteristics of the semiconductor laser and the use conditions of the semiconductor laser by adding a minimum circuit are disclosed. In the semiconductor laser driving device, the output voltage generated by an operational amplifier circuit by amplifying a voltage difference between a monitoring voltage (Vm) and a predetermined reference voltage (Vref) is transmitted to a bias current generating circuit unit as a bias current setting voltage (Vbi) through a sample/hold circuit having a switch (SW1) and a sample/hold capacitor (Csh). When the bias current setting voltage (Vbi) is greater than a predetermined voltage, a deterioration detecting circuit transmits a deterioration detecting signal indicating that the deterioration of the semiconductor laser is detected.

Abstract: An apparatus is provided. The apparatus includes a lasing element, a laser driver and logic. The laser driver is configured to drive the lasing element at multiple current levels, and the laser driver includes a switching network, multiple direct current (DC) loops, and an output circuit. The switching network receives a differential input signal, and each DC loop is coupled to the switching network. The output circuit is also coupled to the lasing element, and the logic is coupled to each of the DC current loops, where the logic selects one or more of the DC loops in each (of several) modes. Each mode generates one or more output lasing currents for the lasing element that corresponds to a one or more of the current levels in response to the differential input signal.

Abstract: An algorithm to drive a semiconductor laser diode (LD) is disclosed. The algorithm assumes that the modulation current to keep the extinction ratio in constant has temperature dependence represented by an exponential function under the average output power of the LD is kept constant by an auto-power-control (APC). When a tracking error exists and the approximation by an exponential function is turned out in failure, the algorithm adds a correction to the exponential function determined by a difference between a practically measured modulation current and another modulation current calculated from a value determined for a bared LD.

Abstract: Methods and systems for generating pulses of laser radiation at higher repetition rates than those of available excimer lasers are disclosed that use multiple electronic triggers for multiple laser units and arrange the timings of the different triggers with successive delays, each delay being a fraction of the interval between two successive pulses of a single laser unit. Methods and systems for exposing nanoscale patterns using such high-repetition-rate lasers are disclosed.

Abstract: The performance of a laser scanner is optimized in the field by automatically determining appropriate laser parameters for the scan location. A laser control system uses information such as the environmental temperature to select an appropriate range of start points for various laser parameters, such as pump temperature and laser currents. Test pulses over that range can be used to determine optimal operating parameters.

Abstract: In one embodiment, a transmitter can bias a vertical-cavity surface-emitting laser (VCSEL) coupled to an optical medium. The biasing of the VCSEL determines at least in part an optical power output by the VCSEL to the optical medium. The transmitter can also modulate the VCSEL with data to transmit the data optically through the optical medium to a receiver; receive from the receiver through a feedback channel an error vector representing a degradation in performance of the VCSEL sensed by the receiver or an instruction vector comprising one or more coefficients for use in biasing the VCSEL; and adjust the biasing of the VCSEL based on the error vector or the instruction vector to regulate the optical power output by the VCSEL to the optical medium.

Abstract: A quantum cascade laser includes a substrate having a first surface, a second surface opposite the first surface, and a recess provided in the second surface; a semiconductor region provided on the first surface of the substrate; a ridge portion extending in one direction on the semiconductor region; a first electrode provided along the ridge portion; and a second electrode provided on the second surface of the substrate. Furthermore, the semiconductor region includes a first cladding layer of n-type, a core layer, and a second cladding layer of n-type stacked in that order. The recess is provided at a position corresponding to the ridge portion in the second surface of the substrate, and the second electrode is provided in the recess.

Abstract: A semiconductor light emitting device includes a pump light source, a gain structure, and an out-coupling mirror. The gain structure is comprised of InGaN layers that have resonant excitation absorption at the pump wavelength. Light from the pump light source causes the gain structure to emit light, which is reflected by the out-coupling mirror back to the gain structure. A distributed Bragg reflector causes internal reflection within the gain structure. The out-coupling mirror permits light having sufficient energy to pass therethrough for use external to the device. A frequency doubling structure may be disposed between the gain structure and the out-coupling mirror. Output wavelengths in the deep-UV spectrum may be achieved.

Abstract: A pulse width modulation method for controlling the output power of a pulsed gas discharge laser powered by a pulsed RF power supply comprises delivering a train of digital pulses to the RF power supply. Each pulse in the train has an incrementally variable duration. The power supply is arranged to deliver a train of RF pulses corresponding in number and duration to the train of digital pulses received. The average power in the RF-pulse train can be varied by incrementally varying the duration of one or more of the digital pulses in the digital pulse train. The train of RF pulses is used to power a gas discharge laser. The gas discharge laser outputs a pulse train corresponding to the RF pulse train.

Abstract: The present invention provides a method of driving a semiconductor laser, where the method can control changes in the internal temperature of a device as well as control optical output using a driving current. A method of driving a semiconductor laser includes steps of: preliminary driving the semiconductor laser by preliminary activating at a current value larger than a threshold value; de-activating the semiconductor laser, after the step of preliminary driving; and starting a formation of a latent image on a photosensitive drum based on a latent image formation signal, after the step of de-activating.

Abstract: An algorithm to drive a semiconductor laser diode (LD) is disclosed. The algorithm assumes that the modulation current to keep the extinction ratio in constant has temperature dependence represented by an exponential function under the average output power of the LD is kept constant by an auto-power-control (APC). When a tracking error exists and the approximation by an exponential function is turned out in failure, the algorithm adds a correction to the exponential function determined by a difference between a practically measured modulation current and another modulation current calculated from a value determined for a bared LD.

Abstract: A laser bias control and monitoring circuit receives a monitor diode current on an input node and generate a bias current for a laser diode on an output node where the monitor diode current flows into (positive polarity) or out of (negative polarity) the input node. The laser bias control and monitoring circuit includes a polarity independent current sensing circuit configured to receive the monitor diode current in either positive or negative polarity and to generate a normalized output current having a magnitude proportional to a magnitude of the monitor diode current. In this manner, the laser bias control and monitoring circuit can be used with laser diode and monitor diode combination in either the common anode or the common cathode configuration, or with the monitor diode current being provided from the anode or cathode of the monitor diode. No reprogramming or reconfiguration of the circuit is required.

Abstract: A laser light source experiencing an EOL condition, which might otherwise cause an unscheduled shutdown, is instead operated in a diminished capacity in one or more predetermined or calculated increments. Operating in such diminished capacity continues until the laser system can undergo appropriate maintenance either during a regularly scheduled shutdown or a newly scheduled shutdown. In the meantime, the diminished capacity of the laser system is accommodated by the utilization tool, as appropriate.

Abstract: An optical writing device includes a light source that emits multiple laser beams; a separating unit that separates each of the multiple laser beams into a monitor beam and a scanning beam; a photoelectric converting element 218 that outputs a monitor voltage depending on a quantity of the monitor beam; a memory that stores an initial correction value for correcting a set common current; and a microcontroller that calculates a reference current, which is produced by correcting the common current updated on the basis of the monitor voltages with the initial correction values, obtains corrected currents by correcting the common current with the calculated correction values, controls each quantity of the laser beam on the basis of the corrected currents, and determines that the light source is degraded if a ratio of the corrected current to the reference current is larger than a predetermined threshold value.

Abstract: An object is to provide a wavelength-tunable laser apparatus that prevents a grid-hopping upon wavelength change, and a wavelength changing method thereof. A wavelength-tunable laser apparatus 101 according to the present invention includes a semiconductor optical amplifier 102 and a periodic wavelength-selection filter 106. Further, the wavelength-tunable laser apparatus 101 includes a phase control unit 111 that concurrently controls a current applied to the semiconductor optical amplifier 102 and a phase tuning of a wavelength-tunable laser under an open-loop control. Thus, dark-tuning can be achieved.

Abstract: The radiance of a laser is a function of drive current. The radiance is also a function of other factors, such as age and temperature. A laser projection device adjusts laser drive parameters using a gradient descent operation. The device parameters may be adjusted iteratively and periodically. The period may be shorter or longer than a scan line in a video image.

Abstract: A light generation and emission system and method is disclosed. A light generator generates light from a diode at a wavelength between 300 nm and 490 nm. A light beam forming subsystem forms the light to a directional light beam, and a controller that controls and directs the directional light beam to a target. The light generator can be suitably used for aiming, target acquisition, communication, identification, scanning, surveying, tracking, ignition and weapons operation.

Abstract: It is disclosed a method for driving a laser diode such as to enable mitigation or elimination of so called spiking effects related to the number of injected carriers in the laser overshooting the equilibrium value at the beginning of the lasing process. In this manner, among other things, the efficiency of a master oscillator power amplifier that may be utilized in range finding applications will be improved. It is further disclosed an optical pulse transmitter comprising such a laser diode.

Abstract: Various embodiments of the present invention relate to a laser driver, and more particularly, to systems, devices and methods of applying low current pulses to a laser modulation current to reduce the speckling noise on the projected images.

Abstract: A laser emission device comprises a plurality of laser elements, a plurality of laser driving power supplies, optical elements which uniformize the laser light amount distributions of laser lights, plural light-receiving elements, a measurement unit which measures at least the relations between the operation current values of the laser elements and the output power values of the laser lights with respect to the operation current values, and the control unit operates the laser driving power supplies according to the operation current values and the output power values so as to make the light output powers of the laser elements different from each other.

Abstract: Disclosed is a high current radiation system. The system includes a high current radiation source to generate radiation and an analog circuit to generate, based, at least in part, on an input signal representative of the present current level delivered to the high current radiation source and a user-controlled input representative of a desired current level, an output signal to control a current level to be delivered to the high current radiation source. The system further includes a current driver to control the current delivered to the high current radiation source based, at least in part, on the output signal of the analog circuit.

Abstract: A light source device including a semiconductor light emitting element and a control section for controlling the semiconductor light emitting element in accordance with an input value. The control section includes a supply section that supplies the semiconductor light emitting element with a drive current based on the input value and an estimated threshold current of the semiconductor light emitting element, and an estimation section that obtains the estimation of the threshold current using the drive current and the amount of light detected to be emitted from the semiconductor light emitting element.

Abstract: The radiance of a laser is a function of drive current. The radiance is also a function of other factors, such as age and temperature. A laser projection device adjusts laser drive parameters using a gradient descent operation. The device parameters may be adjusted iteratively and periodically. The period may be shorter or longer than a scan line in a video image.

Abstract: Output pulses from an optical system having a seed source and an optical amplifier coupled to the seed source may be controlled by controlling a power of a seed signal from the seed source. The seed signal may be varied between a minimum value and a maximum value in a way that the seed signal exhibits one or more pulse bursts. Each pulse burst may contain one or more pulses. During an inter-pulse period between successive pulses within a pulse burst or between successive pulse bursts, the power of the seed signal may be adjusted to an intermediate value that is greater than the minimum value and less than the maximum value. The intermediate value is chosen to control a gain in the optical amplifier such that a pulse or pulse burst that follows the period exhibits a desired behavior.

Abstract: An apparatus includes an array of lasers, an array of electrical drivers, and optical filter. Each laser is configured to produce light in a corresponding wavelength-channel, wherein the wavelength-channels of different ones of the lasers are different. The electrical drivers are connected to directly modulate the lasers. Each driver produces a first driving current or voltage to cause a corresponding one of the lasers to be in a first lasing state and produces a different second driving current or voltage to cause the corresponding one of the lasers to be in a different second lasing state. The optical filter is connected to receive light output by the lasers. The optical filter selectively attenuates light from each of the lasers in the first lasing states thereof and to selectively pass light from each of the lasers in second lasing states thereof.

Abstract: A display device (100) of the present invention has a first switch (3) and a second switch (4) on an upper surface of its casing, and includes a control circuit (18) for controlling the first switch (3) and the second switch (4) and a light source (19) inside the casing. The control circuit (18) performs control so that the light source (19) is turned on when the second switch (4) is pressed after a predetermined period of time has passed from when the first switch (3) was pressed. Thereby, the display device (100) of the present invention prevents entering of a person into a projection area before projection of video, and controls inadvertent start-up.

Abstract: A laser driver to drive an LD in the shunt mode and driven with signals complementary to each other is disclosed. The driver includes two FETs of the enhancement and a terminator. Two FETs are connected in parallel with the LD and driven by the complementary signals but have sizes different from each other. The terminator is connected between respective gate terminals of the FET. The driver further includes a capacitor that compensates the difference in the size of two FETs, which is substantially equal to a magnitude of the junction capacitance of the FET. The capacitor is integrated with the FETs.

Abstract: A method and apparatus are disclosed for controlling bandwidth in a multi-portion laser system comprising a first line narrowed oscillator laser system portion providing a line narrowed seed pulse to an amplifier laser system portion, may comprise utilizing a timing difference curve defining a relationship between a first laser system operating parameter other than bandwidth and the timing difference and also a desired point on the curve defining a desired timing difference, wherein each unique operating point on the curve corresponds to a respective bandwidth value; determining an actual offset from the timing difference at the desired point on the curve to an actual operating point on the curve; determining an error between the actual offset and a desired offset corresponding to a desired bandwidth; modifying the firing differential timing to remove the error between the actual offset and the desired offset.

Abstract: A laser control method includes the steps of: using a laser control circuit which includes a constant current circuit that maintains a constant current flowing through a semiconductor laser element, and which includes an adder and a multiplier connected to a stage preceding the constant current circuit, and using detection means for calibration for detecting an applied laser output; calculating, on the basis of a detection signal output from the detection means, a reference bias value and a reference gain value for obtaining a specified laser output with respect to a specified input to the multiplier; inputting the reference bias value and the reference gain value to the adder and the multiplier, respectively; and controlling the applied laser output from the semiconductor laser element by performing calibration.

Abstract: A current drive circuit according to the present invention includes: a first current source and a second current source (I101, I102); a first current mirror (CM103) for generating a first mirror current of a current (I2) generated by the second current source (I102); a second current mirror (CM106) for generating a second mirror current of the current (I2) generated by the second current source (I102); and a third current mirror (CM101) for generating a mirror current (IOUT1) of a current which is generated by the first current source (I101) and which is corrected according to a difference between the first mirror current and the second mirror current, to supply the current to a load (LD101).

Abstract: Techniques are disclosed that enable fine features such as serifs and narrow strokes of texts to be produced by xerographic devices, for example. The fine features may be generated by subpixels which are produced when a pulse width used to image a pixel is shorter than a corresponding physical size of a laser beam spot used to write the image on a Xerographic photoreceptor. The laser driver may be modified to drive a light emitting element with a boost current profile that includes an overshoot above a steady state current at a rising edge. The overshoot results in a light intensity time profile that has an increased area for a subpixel.

Abstract: An apparatus includes a window to absorb and/or reflect a radiation of a laser light. The apparatus may include a continuous material affixed to the window to transfer energy through the continuous material in a continuous pattern such that an alteration of the continuous material from the laser light of a laser adjusts a power of the laser light of the laser. The window may be a transparent shield to allow a user to view the laser process and to protect the user from the radiation of the laser light. The continuous material may be a wire. The wire may be a string of a conductive material. Examples of the conductive material may include platinum, silver, iron, copper, aluminum, gold, brass, bronze, conductive plastic, and/or semiconductor. The alteration may be damage to the wire to interrupt the current of the electricity through the wire.

Abstract: Provided is a method for driving a surface emitting semiconductor laser including an active region that generates light, a resonator structure disposed such that it sandwiches the active region, and a driving electrode that provides power to the active region. The surface emitting semiconductor laser has an internal resistance defined by voltage and current applied to the driving electrode. The method includes applying a modulation signal to the driving electrode, in which the modulation signal has a current amplitude defined by a first current value and a second current value that is greater than the first current value. The modulation signal is in a negative gradient region in which the internal resistance decreases in contrast to the increase of the current.

Abstract: Methods and systems for increasing the threshold for stimulated Brillouin scattering are described. A seed source may generate one or more chirped seed pulses characterized by a pulse duration ?, and a frequency chirp. The pulse duration ? may be greater than about 2 nanoseconds. A photonic crystal amplifier amplifies the seed pulses to produce one or more amplified pulses characterized by a peak power P greater than about 1 kilowatt. The pulse duration ?, frequency chirp, and the photonic crystal fiber may be selected such that a threshold for stimulated Brillouin scattering (SBS) in the photonic crystal fiber is greater than the peak power P.

Abstract: Many approaches to tunable lasers use an array of DFBs, where each element of the array has a different wavelength. In some operations one element of the array is activated at a time depending on the desired wavelength. For modulated applications, an RF voltage is applied to a specific element of the DFB array, generally using an RF switch. In standard configurations, the demands on the switch are relatively difficult, generally requiring low RF insertion loss and good high frequency performance to 10 GHz. The DFB arrays are generally common cathode or common anode, depending on the type of the substrate used to fabricate the devices. Described herein is an array with a common cathode or anode configuration using a MEMS based switch that shorts the selected laser to RF ground. With this topology, preferably the off-state capacitance should be low with the MEMS switch.

Abstract: A multi-band (multi-color) multiwavelength mode locked laser diode is provided by dynamic phase compensation of a quantum dot active medium. The laser diode is provided with a PIN diode structure where the active medium consists of a plurality of layers of quantum dots such as those produced by self-assembly from known chemical beam epitaxy methods. The multiplicity of bands may be produced by AC Stark splitting, frequency selective attenuation, or by the inclusion of multiple different layers having different, respective, peak ASE emissions. Dispersion compensation within laser facets, waveguides, and the optically active media permit the selection of a fixed dispersion within the cavity. A dynamic group phase change induced by the AC Stark effect permits compensation of the fixed dispersion sufficiently to produce an intraband mode-locked laser. Even interband mode locking was observed.

Abstract: A circuit for driving a light-emitting element such as a laser diode LD has a boost circuit for boosting an input voltage to supply it to the light-emitting element, a photoreceptor such as a photodiode PD for monitoring light from the light-emitting element; and a boost control circuit for controlling a boost voltage of the boost circuit based on a monitored amount of the photoreceptor. In the method for driving a light-emitting element by boosting an input voltage to supply the voltage to the light-emitting element, light from the light-emitting element is monitored and its monitored amount is used as a basis to control a boost voltage to the light-emitting element. A control circuit may be provided to control a driving current that passes through the light-emitting element based on the monitored amount of the photoreceptor.

Abstract: Systems and methods for controlling a thermoelectric cooler (TEC) in an optical transceiver. A TEC system includes a processor that interacts with a power supply and a TEC controller to prevent inrush current. The power supply is switched by the processor and turned on only at a particular time. The power supply has a relatively large time constant such that it ramps slowly to its full value. In the meantime, the processor and TEC controller cause the temperature to ramp to a target value by repeatedly incrementing or decrementing a target value over time and by controlling when the maximum available voltage can be applied to the TEC.

Abstract: An ultrashort pulse/ultra-high power laser diode with a simple structure and configuration. The laser diode can be driven by a pulse current which is 10 or more times higher than a threshold current value. The width of the pulse current is preferably 10 nanoseconds or less, and the value of the pulse current is specifically 0.4 amperes or over.