Abstract: Average-power control loops and methods through laser supply voltage closed-loop control. In accordance with one of the methods, a switching converter is coupled to provide power to a first terminal of a laser diode, a programmable current source is coupled to control the average current through a laser diode, an average power control circuit is coupled to a monitor diode to monitor the average power out of a laser diode and to control the programmable current source to maintain a desired average power out of a laser diode, and the output of the switching converter is adjusted responsive to the headroom of the programmable current source to limit the output of the switching converter to a voltage that will still assure adequate operation of the current source. Various embodiments are disclosed.

Abstract: An LD-Driver with the push-pull arrangement is disclosed. The driver includes the high side driver driven by the positive phase signal and the low side driver driven by the negative phase signal. When the positive phase signal is in HIGH, the high side driver becomes ON and the LD driver provides additional current to the bias current for the LD; while, when the negative phase signal is in HIGH, the low side driver becomes ON and the LD driver extracts a portion of the bias current for the LD.

Abstract: Various embodiments of the present invention provide single-ended and differential current drivers for heat assisted magnetic recording and other applications. For example, a current driver is disclosed that includes an upper output terminal and lower output terminal, a number of current switches operable to selectively contribute electrical currents through the upper and lower output terminals, a control input for each of the current switches operable to control the electrical currents, and a voltage supply operable to establish a voltage across the upper and output terminals.

Abstract: The present invention relates to a pulse modulation method and the like having a structure for effectively suppressing nonlinear optical phenomena which increase as an optical pulse becomes wider when amplifying the optical pulse with a predetermined period as seed light. A modulator performs pulse modulation for a laser light source which is a seed light source or light outputted from the laser light source. A modulation pattern of a modulated voltage outputted from the modulator is adjusted such as to include a plurality of pulse components each having a signal width shorter than the pulse width of the optical pulse as an optical pulse generation pattern within a modulation period corresponding to a period of the optical pulse.

Abstract: A method of driving a GaN-based semiconductor light emitting element formed by laminating a first GaN-based compound semiconductor layer having a first conductive type, an active layer having a well layer, a second GaN-based compound semiconductor layer having a second conductive type, includes the steps of: starting light emission by the start of the injection of carrier; and then stopping the injection of the carrier before a light emission luminance value becomes constant.

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 transmission module includes a bias current driver circuit adapted to input bias current set in response to a temperature of a laser diode to the laser diode, a modulation current driver circuit adapted to input modulation current set in response to the temperature of the laser diode to the laser diode, and a decision circuit adapted to decide whether or not an error of optical output power of the laser diode detected by a light reception device with respect to a target value of the optical output power of the laser diode at the set bias current and the set modulation current is equal to or higher than a threshold value. The modulation current driver circuit inputs, while the error is equal to or higher than the threshold value, correction modulation current higher than the set modulation current to the laser diode.

Abstract: A method of closed loop control for an optical link is presented, utilizing a copper feedback connection between the optical transmitter and optical receiver, suitable for short distance applications. An architecture is provides that may be used to define and maintain an optimum optical launch power for a defined bit error rate, guaranteeing extinction ratio and absolute optimum operating power. The invention also includes the use of such a loop in achieving fast link initialization and dynamic optimization to compensate for all effects of time and temperature for all components within the link.

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 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: A control circuit for a fiber amplifier having a first stage pump and at least one second stage pump and method of controlling thereof is disclosed. The control circuit includes a control gate controlling a current through the first stage pump. A sensor for detecting a voltage across the first stage pump and providing a measured output of the voltage is provided. The control circuit further includes a control loop configured for selectively controlling the current through the control gate in accordance with the measured output and a set reference point is also provided.

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: 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: The present disclosure relates to an optical power monitoring circuit including an automatic power control (APC) loop and a microcontroller unit (MCU), and a method for monitoring the same. The APC loop comprises a laser diode (LD) and a feedback loop to maintain a laser optical power. The MCU is configured to (i) monitor a bias current using a current sense circuit, (ii) monitor a rate of change of the bias current with time, and (iii) adjust a target power of the APC loop. By monitoring the bias current and the rate of change, and comparing them against thresholds, the target power can be adjusted by the MCU, to prevent roll-over in the laser diode, damage to the laser, and/or a hard failure in the data links that use the laser.

Abstract: A high-power laser unit capable of accurately correcting laser output from low to rated outputs, even when the laser unit has a laser power monitor which may be affected by environmental factors inside or outside the laser unit, by effectively reducing environmental factors. The laser unit has a laser power monitor for measuring laser output, and a laser controller for correcting the laser output by correcting an amount of excitation energy to a laser power supply so that a measurement value coincides with a laser output command value. The laser unit has a laser output commanding part for generating a laser output command. When it is not necessary to correct the laser output command, the laser output command is converted into an excitation energy command value and sent to the power supply. Otherwise, an output correcting part of the laser controller corrects the laser output command.

Abstract: An active laser guarding system 1 comprises at least one screen 3 provided with at least two spaced apart conductors 7, 9 each defining a respective electrically conductive path that is electrically separate from the other. The screen 3 comprises material, at least between the two conductors 7, 9, which is arranged to carbonize when struck by a laser beam to form a further conductive path 19 which extends between, and electrically connects, the two conductors 7, 9. The system 1 further comprises a detector 15 operative to detect the further conductive path 19 so formed, the detector 15 being operative to generate a laser deactivation signal response to detecting the further conductive path 19.

Abstract: A laser driving device includes: a pulse signal generating unit that, after a voltage has risen from a predetermined reference voltage to a predetermined output voltage and a time of a sum of an oscillation period of relaxation oscillation and a light emission start time in a predetermined laser diode has nearly elapsed, generates a pulse signal having a waveform that falls divisionally in two or more stages from the output voltage to the reference voltage; and an output unit that generates a laser drive signal by performing signal processing on the pulse signal and outputs the signal to the laser diode.

Abstract: A laser diode read driver includes a first transistor producing a first voltage in response to receiving a first current signal. A transconductor has a first input coupled to receive the first voltage and produces a second current signal in response to differences between signals received on the first input and a second input. A second transistor is coupled to the second input and produces a third current signal in response to receiving the second current signal. A third transistor is coupled to the second transistor and the second input and produces an output current signal in response to receiving the third current signal. The first transistor is scaled to the first transistor by the inverse of a gain factor. First and second resistors are coupled between the first and third transistors and a low voltage supply, and are scaled to each other by the gain factor.

Abstract: Radio-frequency (RF) power supply apparatus for supplying RF power to discharge electrodes of a gas-discharge laser includes a plurality of amplifier modules each having an RF output. A power combining arrangement is provided for combining the amplifier module RF-outputs into a single combined RF-output connected to the discharge electrodes. A DC power supply is connectable to or disconnectable from each of the transistor amplifier modules, separately, to allow current drawn by any of the amplifier modules to be monitored by a single current sensor.

Abstract: A disclosed laser diode driving device drives laser diodes with driving currents obtained by adding switch currents to corresponding bias currents and includes a common switch current generating circuit configured to generate a common switch current according to an input signal; switch current generating circuits provided for the corresponding laser diodes and configured to generate the switch currents based on the common switch current and input signals; switches configured to control the output of the switch currents to the corresponding laser diodes according to input signals; bias current generating circuits configured to generate the bias currents and output the generated bias currents to the corresponding laser diodes; and a control unit configured to detect the light intensities of the respective laser diodes and to control the common switch current generating circuit, the switch current generating circuits, and the switches to adjust the light intensities of the respective laser diodes.

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: An RF powered CO2 gas-discharge laser includes discharge electrodes and a lasing gas mixture between the electrode. The lasing gas mixture is ionized when the RF power is applied to the electrodes and laser action is initiated when the RF power has been applied for a duration sufficient to ignite a discharge in the lasing gas mixture. The gas mixture is pre-ionized by periodically applying the RF power to the electrodes for a predetermined period during which ignition of a discharge is not expected to occur. RF power reflected back from the electrodes is monitored. If the monitored power falls below a predetermined level indicative of the imminent onset of laser action before the predetermined duration has elapsed, application of the RF power to the electrodes is terminated to prevent the laser action from occurring.

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: A method to control an LD (laser diode) is disclosed. The method compares the operating temperature of the LD with a transition temperature. When the former temperature exceeds the latter, the modulation current is set based on the bias current, which is independently determined by the APC loop. On the other hand, the operating temperature is less than the transition temperature; the modulation current is determined by the operating temperature.

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: An LD driver is disclosed where the power dissipation is reduced without enlarging the circuit scale. The LD driver, which drives a tunable LD including a SG-DGB region, a CSG-DBR region, and an SOA region, includes a DC/DC converter connected to current sources or voltage sources each coupled with at least two regions of the SG-DFB, CSG-DBR and SOA regions, and a voltage controller to control the output of the DC/DC converter which is commonly provided to the current sources or the voltage sources. The voltage controller independently monitors the bias conditions of the at least two regions above, and sets the output of the DC/DC converter so as to exceed a largest voltage among voltages currently provided to respective regions by a preset margin to operate the current sources or the voltage sources normally.

Abstract: A surface emitting laser apparatus includes an arithmetic processing unit including an I/O unit for externally inputting an instruction and a core unit that performs an operation based on the instruction and outputs a differential voltage signal modulated with a predetermined amplitude according to a result of the operation, capacitors respectively arranged on output paths of the differential voltage signal, and a surface emitting laser device that is directly connected to the arithmetic processing unit via the capacitors. An I/O voltage and a core voltage are externally supplied to the I/O unit and the core unit, respectively. The arithmetic processing unit generates a driving voltage signal by superimposing the differential voltage signal with the core voltage commonly supplied as a bias voltage without stepping up or down the core voltage and without amplifying the differential voltage signal and supplies the driving voltage signal to the surface emitting laser device.

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: A first transistor produces a first voltage in response to a first current signal. A first resistor is coupled between the first transistor and a low voltage supply. A transconductor has a first input receiving the first voltage and producing a second current signal in response to differences between signals received on the first input and a second input. A second transistor is coupled to the second input and produces a third current signal in response to the second current signal. A third transistor, coupled to the second transistor and the second input, produces an output current signal in response to the third current signal. The first transistor is scaled to the third transistor by the inverse of a gain factor. A second resistor is coupled between the third transistor and a low voltage supply. The first resistor is scaled to the second resistor by the gain factor.

Abstract: A semiconductor optical amplification module that can suppress ringing without increasing power consumption or circuit size or inhibiting high-speed operation. A semiconductor optical amplifier outputs an optical signal inputted according to driving current outputted from a drive circuit. A diode is connected in parallel with the semiconductor optical amplifier. As a result, it becomes possible to suppress ringing without connecting a large resistor to the drive circuit.

Abstract: A digital-to-analog (DA) converter includes: an analog output section that generates an output current corresponding to a value of a digital signal in response to a bias voltage and outputs an analog signal which is obtained from the output current by current-to-voltage conversion; a current source; a current control section that converts a current from the current source to a voltage signal and outputs the voltage signal as the bias voltage; and a sample and hold circuit section that samples and holds the bias voltage from the current control section and supplies the held bias voltage to the analog output section.

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 diode drive circuit includes: a duty control amplifier (23) that controls the duty ratio of a main signal for laser control in accordance with a duty control signal; and an AND gate (22) that outputs the duty control signal to the duty control amplifier (23), and outputs a duty control signal that controls the duty ratio of the main signal to be 0% in the duty control amplifier in accordance with a shutdown signal of a laser diode. With this structure, there is no need to input the main signal having the duty ratio controlled to a logic circuit that becomes unstable. Thus, outputs from a semiconductor laser can be shut down, and the output duty can be controlled in a stable manner.

Abstract: An apparatus comprising: a processor for determining if a laser is operating in a single-mode state and for determining the degree to which one of one or more tunable parameters for the laser must be adjusted so that laser operates in a single-mode state if not operating in a single-mode state, wherein the one or more tunable parameters include the following parameters: the laser current and the wavelength of the output light. The apparatus may include a laser and/or a holographic storage medium. Also provided is a method for determining if a laser is operating in a single-mode state and for determining the degree to which one of one or more tunable parameters for the laser must be adjusted so that laser operates in a single-mode state if not operating in a single-mode state.

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: An optical transmitter includes a light-emitting device and an optical modulator that modulates light output from the light-emitting device by using an input signal. The optical transmitter includes a drive current switching controller that performs an ON/OFF switching control of a drive current of the light-emitting device, by using an ON/OFF signal as an input that controls ON/OFF of an optical output of the light-emitting device, in response to a switching of the ON/OFF signal. The optical transmitter also includes a drive current adjusting and generating unit that detects an ambient temperature, and generates a drive current that is adjusted according to the ambient temperature detected thereby. The drive current switching controller includes a differential circuit that is supplied a drive current that is generated by the drive current adjusting and generating unit and controls the drive current that is output to the light-emitting device, according to the ON/OFF signal.

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 gas laser oscillator capable of initiating discharge, without applying excess voltage to a discharge tube, and correctly and rapidly judging the initiation of discharge. The oscillator has a laser power commanding part adapted to generate a laser power command including a pulse superimposed on a forefront of each step, a voltage applying part adapted to apply a voltage to a discharge tube based on the laser power command, a discharge tube voltage detecting part adapted to detect the discharge tube voltage, a discharge tube voltage monitoring part adapted to monitor the discharge tube voltage, and a discharge initiation judging part adapted to judge that the discharge is initiated when the difference, between a change rate of the monitored voltage and a change rate of the discharge tube voltage predetermined based on data obtained while the discharge is normally carried out, is smaller than a predetermined threshold.

Abstract: The present patent application provides a low power consumption pump driving circuit including a laser cooling chip, a PMOS transistor, a NMOS transistor, a LC filter circuit, a laser, and a voltage sampling circuit. The pulse width modulating signal generated by the laser cooling chip and the control terminal of the PMOS transistor are connected to the gate of the PMOS transistor. The source of the PMOS transistor is connected to a power supply. The drain of the PMOS transistor is connected to the LC filter circuit. The other terminal of the LC filter circuit is connected to the anode of the laser. The cathode of the laser is connected to the drain of the NMOS transistor. The source of the NMOS transistor is connected to the ground. One terminal of the voltage sampling circuit is connected to the laser. The other terminal of the voltage sampling circuit is connected to the laser cooling chip.

Abstract: The present invention comprises, in various embodiments, systems and methods for shutting down a laser system in an intelligent and flexible manner. An intelligent laser interlock system includes both hardwired components, and intelligent components configured to execute computing instructions. The hardwired components and the intelligent components are configured to shutdown the laser system to one or more alternative shutdown states in response to one or more interlock signals.

Abstract: A laser device includes a plurality of lasers that includes a first laser and a second laser. The laser device further includes a drive circuit configured to apply a pulsed current to the first laser at a first phase. The drive circuit is further configured to apply the pulsed current to the second laser at a second phase. The first phase and the second phase are different. A total voltage provided to the plurality of lasers during a period between the first and second phases is substantially smaller than a sum of individual voltages provided to the plurality of lasers, respectively, during a pulse period of the pulsed current.

Abstract: The invention relates to an integrated driver circuit suitable for driving a light emitter with a signal current I(time) based on a received signal said circuit comprising a differential pair of transistors having a first transistor and a second transistor each respectively forming part of a first branch and a second branch, said first branch comprises a node suitable for connecting to said light emitter and/or said first branch comprises said light emitter, wherein said second branch comprise at least one charge storage device. This charge storage device may be arranged to collect current otherwise wasted in the process of driving the light emitter. This current may be utilized to drive circuitry thereby reduce current consumption.

Abstract: A laser device includes a semiconductor laser, a signal generating circuit generating a pulse signal for driving the semiconductor laser, an amplifying circuit amplifying the pulse signal, and a control circuit unit provided between the amplifying circuit and the semiconductor laser and controlling the pulse signal by letting alternating-current components of the pulse signal pass through and removing at least part of direct-current components of the pulse signal.

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: An optical-switch drive circuit including a driver unit that generates, in response to a control signal, an on/off signal for driving a semiconductor optical amplifier gate switch, and a buffer unit having a high input impedance and connected between an output terminal outputting the on/off signal and the semiconductor optical amplifier gate switch. In the optical-switch drive circuit the buffer unit may include a high-resistance voltage divider that is connected with the output terminal, and an operational amplifier that buffers, and provides to the semiconductor optical amplifier gate switch, a divided voltage of the voltage divider.

Abstract: Apparatus and method for driving laser diodes with electrical power in pulsed operation. Pulsed power, for example using pulse-width modulation, is applied through an inductor in one or more parallel regulator circuits having little or no output capacitance to provide a high-efficiency laser-diode-driver power supply. Some embodiments that use two or more parallel regulator circuits in the laser-diode driver, drive each from a different phase of a clock signal. Some embodiments provide a first DC-to-DC converter has a relatively high-voltage input (e.g., about 275 volts, 0.75 amps) and an intermediate output of, e.g., 11 to 15 volts, 15 to 11 amps used to charge a storage capacitor, and a second DC-to-DC converter diode driver having one or more parallel circuits (each having, e.g., a PWM switching-mode controller and its respective switch, inductor, and diode) to turn on, regulate, and turn off a constant laser-diode current through one or more laser diodes.

Abstract: A light output control device for laser light sources for respective RGB colors includes, for each of RGB, three sets, each including: a semiconductor laser for one of the colors; light output detection unit for detecting a light output from the semiconductor laser; light output adjustment unit for updating a light output target value; light output control unit for controlling the semiconductor laser based on the updated light output target value; and division unit for dividing the light output by an output from the light output adjustment unit to obtain a ratio of the rising of the light output, and includes rising determination unit for determining, based on results obtained by the respective division unit, a semiconductor laser with a slowest rising and outputs light output adjustment values for the respective colors. The light output adjustment unit update their respective light output target values based on the light output adjustment values.

Abstract: A fiber laser processing apparatus controls a LD drive current ILD in a power feedback control mode (FIG. 3E) such that output of a fiber laser beam FB rises substantially from zero or a value around zero to a preceding level having no substantial effect on laser processing and arrives at a desired level (PA) for the laser processing from a preceding level PB after a first time period (preceding pulse width TB) has elapsed (time point t2 of FIGS. 3A to 3F) from the start of the rising to the preceding level (time point t1 of FIGS. 3A to 3F), and this may effectively prevent occurrence of a high-peak pulse HP at the rising edge of the fiber laser beam FB (FIG. 3F).