Abstract: Disclosed is a bio illuminance measuring apparatus including a circadian lambda filter passing external light along according to a circadian rhythm sensitivity curve, a visual lambda filter passing the external light along according to a visual sensitivity curve, a photo sensing portion sensing and converting the external light, which has passed through the circadian lambda filter, into a circadian wavelength signal and sensing and converting the external light, which has passed through the visual lambda filter, into a visual wavelength signal, and an illuminance calculating portion which calculates a ratio between the circadian wavelength signal and the visual wavelength signal, calculates a circadian action factor by applying the ratio between the circadian wavelength signal and the visual wavelength signal to a circadian action function which varies according to the visual wavelength signal, and calculates a bio illuminance value of the external light on the basis of the circadian action factor.

Abstract: Embodiments of the present disclosure are directed towards a laser device with a stepped graded index separate confinement heterostructure (SCH), in accordance with some embodiments. One embodiment includes a substrate area, and an active region adjacent to the substrate area. The active region includes an SCH layer, which comprises a first portion and a second portion adjacent to the first portion. A composition of the first portion is graded to provide a first conduction band energy increase over a distance from multiple quantum wells (MQW) to a p-side of a laser device junction. A composition of the second portion is graded to provide a second conduction band energy increase over the MQW to the p-side distance. The first conduction band energy increase is different than the second conduction band energy increase. Other embodiments may be described and/or claimed.

Abstract: In a drive unit according to an embodiment of the present disclosure, in each of a plurality of current pulses, a rising crest value is the largest, and after the rising, the crest value is damped. Further, a rising crest value of a pulse of an n+1-th wave is smaller than a rising crest value of a pulse of an n-th wave. Furthermore, rising crest values of the current pulses of a second wave and waves after the second wave are determined by a mathematical function expressed as an electric potential change caused by ON-OFF of an RC time constant circuit that is single-end grounded. Moreover, in the mathematical function, a time constant at an OFF time is larger than a time constant at an ON time.

Abstract: An image recording apparatus includes a plurality of laser emission parts disposed side by side in a predetermined direction for emitting laser light; an optical system configured to collect a plurality of beams of laser light emitted by the laser emission parts onto the recording target moving relative to the laser emission parts in a direction crossing the predetermined direction; and an output control unit configured to perform control such that energy of laser light emitted from an outermost end laser emission part of the laser emission parts is greater than energy of laser light emitted from a center laser emission part, the outermost end laser emission part emitting laser light to be transmitted through vicinity of an end portion of the optical system, the center laser emission part emitting laser light to be transmitted through a portion other than vicinity of the end portion of the optical system.

Abstract: Apparatuses, methods, and systems are disclosed to drive pumping laser diode arrays. In implementations, an integrated system can be constructed to in a compact, efficient and cost-effective manner and to meet the needs of driving laser diode arrays in various diode pumped solid state laser applications. The disclosed implementations include individual laser diode drivers or pulsers, methods of communicating with laser diode drivers, and methods of controlling the pulse shape of each laser diode driver.

Abstract: A display apparatus is provided. The display apparatus is a retinal scanning type display apparatus, and includes a low output laser whose operational current is less than that of a standard output laser; a shunting element that is connected in parallel with the low output laser; and a drive circuit that supplies a current to the low output laser and the shunting element. The drive circuit is a drive circuit for the standard output laser capable of adjusting a current value on a discrete basis in a range of an operational current that is higher than the operational current of the low output laser.

Abstract: A gamma-ray spectrometer calibration system comprises a photomultiplier tube and analysis electronics. The photomultiplier tube provides one or more reference signals that are analyzed relative to a spectrum by the analysis electronics to calibrate a gamma-ray spectrometer. Additional apparatus, methods, and systems are disclosed.

Abstract: A drive apparatus includes a light emitting device, a light receiving device configured to receive light emitted by the light emitting device, a comparison circuit configured to compare a light quantity of light detected by the light receiving device with a target value indicating a light quantity of light to be emitted by the light emitting device and generate a control signal corresponding to a comparison result, and a drive circuit configured to supply a drive signal corresponding to the control signal to the light emitting device. The drive circuit includes a gain changing switch configured to change, in accordance with the target value, a gain of the drive circuit.

Abstract: An electro-optic transceiver module, method of manufacturing, and method of transmitting signals are provided that allow multiple optical signals at different wavelengths (e.g., according to CWDM) to be combined for transmission via a number of optical fibers that is smaller than the number of electrical channels according to which the optical signals were generated. Thus, CWDM may be used in connection with lower-cost VCSEL technology (e.g., as opposed to higher-cost edge-emitting lasers) by providing for wavelength compensation at the VCSEL driver to offset any changes in wavelength that may have otherwise occurred at the VCSELs. In particular, a microcontroller of the electro-optic transceiver module correlates a monitored temperature of the VCSELs to an actual wavelength of the corresponding optical signals transmitted by the respective VCSELS and determined an adjustment in a current supplied by the VCSEL driver to each VCSEL to achieve more precise and consistent wavelengths at the VCSELs.

Abstract: Power leveling a system under test (SUT). An input signal is provided at an initial power level to the SUT. Multiple iterations are performed, each including measuring, over a specified measuring interval, power of a signal produced by the SUT in response to the input signal, and dynamically adjusting the power of the input signal in response. The measuring interval is increased over the iterations, thereby increasing accuracy of the measuring over the iterations while converging the signal to a specified power level. An initial power leveling operation may be performed for the SUT to establish a specified power level, after which the SUT is tested, during which multiple power leveling operations are performed, each including measuring power of a signal from the SUT over a specified measuring interval, and adjusting the input signal in response, thereby maintaining the specified power level during the testing while correcting for thermal droop.

Abstract: Systems and methods of minimizing distortion produced when modulating an optical signal using an electrical signal.

Abstract: Power leveling a system under test (SUT). An input signal is provided at an initial power level to the SUT. Multiple iterations are performed, each including measuring, over a specified measuring interval, power of a signal produced by the SUT in response to the input signal, and dynamically adjusting the power of the input signal in response. The measuring interval is increased over the iterations, thereby increasing accuracy of the measuring over the iterations while converging the signal to a specified power level. An initial power leveling operation may be performed for the SUT to establish a specified power level, after which the SUT is tested, during which multiple power leveling operations are performed, each including measuring power of a signal from the SUT over a specified measuring interval, and adjusting the input signal in response, thereby maintaining the specified power level during the testing while correcting for thermal droop.

Abstract: A tunable optical transmitter, comprising a tunable laser comprising a distributed Bragg reflector (DBR) section, a phase section, and a gain section, a photodiode detector (PD) optically coupled to the tunable laser, wherein the tunable optical transmitter lacks a temperature controller, and wherein the tunable optical transmitter is configured to lock onto a wavelength at different operating temperatures.

Abstract: A method for providing a feedback circuit for a three dimensional projector. First and second input devices and a sensor for determining the rotational speed of the second input device are provided. A control device for controlling the rotational speed of the second input device and a phase locked loop (PLL) are provided. A phase reference signal is created based on the signal rate of the first input device. A phase signal is created based on the rotational speed of the second input device. The PLL compares the phase reference signal and the phase feedback signal to determine whether the first input device and the second input device are synchronized. A signal is sent to the control device for the second input device to change the rotational speed of the second input device in response to determining that the first input device and the second input device are not synchronized.

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: A microlaser system includes an optical source, a microlaser, an actuator switch, and a photovoltaic power source. The microlaser, which includes a control element, is optically pumped by at least a portion of light emitted by the optical source. The actuator switch is configured to be activated by a triggering event. Furthermore, the photovoltaic power source is coupled in a series connection with the actuator switch and the control element, the series connection configured to connect the photovoltaic power source to the control element of the microlaser when the actuator switch is activated by the triggering event.

Abstract: A method for providing a feedback circuit for a three dimensional projector. First and second input devices and a sensor for determining the rotational speed of the second input device are provided. A control device for controlling the rotational speed of the second input device and a phase locked loop (PLL) are provided. A phase reference signal is created based on the signal rate of the first input device. A phase signal is created based on the rotational speed of the second input device. The PLL compares the phase reference signal and the phase feedback signal to determine whether the first input device and the second input device are synchronized. A signal is sent to the control device for the second input device to change the rotational speed of the second input device in response to determining that the first input device and the second input device are not synchronized.

Abstract: A control method of a semiconductor optical amplifier includes: controlling a driving current of the semiconductor optical amplifier in a region where a light output intensity decreases in accordance with increasing of the driving current, a drive current in the region being higher than a drive current in a region where a light output intensity increases in accordance with increasing of the driving current.

Abstract: A projector system that includes a first input device, a second input device, a control device, a sensor and a phase locked loop (PLL). A phase reference signal is created based on a signal rate of the first input device. A phase feedback signal is created based on the rotational speed of the second input device as it is measured by the sensor. The PLL compares the phase reference signal and the phase feedback signal to determine whether the first input device and the second input device are synchronized. A signal is sent to the control device for the second input device to change the rotational speed of the second input device in response to determining that the first input device and the second input device are not synchronized.

Abstract: The invention provides a wavelength-controlled pump MOPA laser and a method of operation thereof. A monolithic semiconductor MOPA laser chip has a DFB-laser based MO (master oscillator) and PA (power amplifier) sections formed in a same monolithic waveguide, and separate MO and PA electrodes for individual control of current injection into the MO and PA sections. The laser wavelength is defined by the DFB grating and is kept fixed by suitably controlling the MO current to compensate for a thermal crosstalk from the PA section, or tuned by suitably changing the MO current or direct heating of the DFB region.

Abstract: There provided is a semiconductor laser control device which including plural light sources that are configured with eight or more semiconductor laser elements, a one detecting section that detects a light power of the light sources, a light power control unit that compares a signal according to a light power detected by the detecting section with a control signal corresponding to a predetermined light power to control a current supplied to the light sources, and a voltage clamp circuit that functions as an overvoltage preventing means for the detecting section when turning on each of the light sources to perform light power control.

Abstract: In a VCSEL driver for automatic bias control and automatic modulation control, the VCSEL driver includes: a feedback module configured to receive an output of a VCSEL to provide a bias signal through a feedback loop; an automatic bias control block configured to adjust a bias current by switching on or off a plurality of power sources, which are connected in parallel with each other; an automatic modulation control block configured to connect in parallel a plurality of bias transistors that are connected to each of the plurality of power sources, and to adjust modulation current by switching each of the plurality of bias transistors on or off; and a main driver configured to provide the VCSEL with a drive current including the bias current and the modulation current, which are adjusted by control of each of the control blocks.

Abstract: A laser diode (LD) driver to suppress the excess emission of an LD is disclosed. The LD driver has the shunt configuration with a driving transistor connected in parallel to the LD to shunt the bias current provided to the LD. The driver further provides a protection circuit to divide the bias current when the bias current is active but the driving transistor is turned off at an instant of the power on and off of the LD driver.

Abstract: A light source including a laser diode, and a method of operating a light source including a laser diode are disclosed. A driving current of the laser diode is dithered to cause a near-field light intensity distribution at an end facet to be perturbed, thereby reducing a time-averaged local intensity of the laser light at the end facet of the laser diode. The reduced time-averaged intensity reduces a possibility of a damage of the end facet.

Abstract: A pulse laser includes a laser medium, a charge storage unit, a power source unit configured to supply an electrical charge to the charge storage unit, an excitation unit configured to cause irradiation of the laser medium with excitation light onto the laser medium by being supplied the electrical charge stored in the charge storage unit, a switching unit configured to repeatedly supply the charge stored in the charge storage unit to the excitation unit, an energy monitoring unit configured to monitor energy stored in the charge storage unit, and a control unit configured to prevent the switching unit from supplying the electrical charge stored in the charge storage unit to the excitation unit when the energy monitored by the energy monitoring unit is larger than a threshold.

Abstract: The invention relates to a method and a device for illuminating or irradiating an object, a sample (8), or the like, for the purpose of imaging or analysis, particularly for use in a laser microscope (1), preferably in a confocal microscope having a laser light source (2) emitting the illuminating light, the laser light being coupled directly or by means of a glass fiber into an illumination light path (4), characterized in that the laser light source (2) is switched on rapidly upon a trigger signal directly prior to the actual need, for example, directly prior to imaging.

Abstract: A method to tune an emission wavelength of a wavelength tunable LD is disclosed. The wavelength tunable LD includes two regions each providing micro heaters to modify the refractive index of micro regions provided with power. The method periodically detects a difference between the emission wavelength and the target wavelength. This wavelength difference is converted into power next supplied to respective micro heaters independently.

Abstract: Embodiments of the present invention use an external cavity laser source with dual input terminals, such as bias current for a gain section, and a voltage signal for a modulator section. An aspect of the present invention provides an ultra-low frequency noise external cavity frequency modulated (FM) semiconductor laser source frequency stabilized by a dual electronic feedback circuitry applied to semiconductor gain section and a modulation section. A further aspect of the present invention provides an optical frequency discriminator based on homodyne phase demodulation using an unbalanced Michelson interferometer with fiber optics delay and a symmetrical 3×3 optical coupler.

Abstract: Some aspects of the present disclosure provide system and method of operation of a driving circuit for a light emitting element in a Time-of-Flight (ToF) camera. A DC-DC converter is configured to emit a constant current, and is coupled in parallel to a first modulation switch configured to connect the driving circuit to ground. The first modulation switch is further configured to alternate connections between the current source and ground at a frequency in a desired range of operation to produce an AC current. In some embodiments, an RC circuit element is coupled to an output electrode of the light emitting element and configured to apply a reverse bias to decrease turn-off time of the light emitting element. In some embodiments, a second modulation switch is coupled to the output electrode and configured to apply the reverse bias across the light emitting element. Other systems and methods are also disclosed.

Abstract: A laser device (100) includes a laser (110; 210; 310; 410; 510) in turn including at least one Distributed Bragg Reflector (DBR) section (111), at least one phase section (112) and at least one gain section (113), further including a laser control element (150), a feedback control element (140) and a frequency noise discriminator (130,131), which feedback control element is arranged to feed a variable feedback signal to at least one of the at least one DBR section and the at least one phase section of the laser, so that the output laser frequency is altered in response to a variation in the feedback signal or the combination of respective feedback signals, whereby the feedback signal or combination of respective feedback signals is varied as a function of the detected frequency fluctuation so as to counteract the detected frequency fluctuation.

Abstract: A method or algorithm to control a driving current supplied to a semiconductor laser diode (LD) is disclosed. the method first prepares the look-up-table (LUT) that stores a set of parameters, ? and ?, for evaluating the modulation current Im by the equation of Im=?×Ib+?, where Ib is determined by the auto-power-control (APC) loop. In a practical operation of the LD, the APC loop determines Ib, while, Im is calculated according to the equation above by reading above two parameters corresponding to the current temperature of the LD from the LUT.

Abstract: Apparatus and systems create differential drive signals suitable for HAMR data recording. A laser diode differential driver provides heating current pulses at a time ?1. The pulses energize a laser diode to pre-heat the magnetic medium to be written. Some embodiments duplicate portions of the laser diode circuit architecture to create a magnetic write head differential driver. The write head driver provides write current pulses to a magnetic write head in one direction with ?1 timing and in the opposite direction with ?2 timing. Both drivers utilize sets of reference voltages capable of being switched to one terminal or the other of the element to be driven. In the laser diode case, the common mode is split between the anode and cathode sections of the driver. A feedback element is added between the cathode and anode sections to provide current accuracy independent of the electrical characteristics of the selected laser diode.

Abstract: A laser machining control system includes a laser diode, a laser power controller connected to the laser diode, a light transmission-reflection element positioned on a light path of a laser light beam to a workpiece, and an output power meter. The output power meter detects the laser light beam being reflected by the transmission-reflection element and measures an output power of the laser diode. The output power meter gives a signal to the laser power controller if there is a power loss of the laser light beam, and the laser power controller adjusts the voltage and the current input to the laser diode in compensation.

Abstract: Circuit arrangement or circuit, in particular driver circuit, and a method for controlling at least one light-emitting component, such as an electro-optical transducer, a light-emitting diode (LED), an electroluminescent diode, a laser, or a semiconductor laser, by switching a switching element between a first switching position and a second switching position, and the voltage supply is effected by a supply element, such as a voltage source or a current source supported by a decoupling capacitor on the output side, so that current drain and output resistance are as low as possible, so that the highest possible frequency or switching speed as well as the highest possible output voltage for the light-emitting component can be achieved, the light-emitting component is controlled by varying its operating voltage, in particular by switching between the switching positions, and the first and second switching positions are of low impedance for the operating frequency.

Abstract: A scanning laser projector includes a scanning mirror that moves in a sinusoidal motion on at least one axis. Pixels are displayed by modulating a laser beam that is reflected by the scanning mirror. Pixels are generated using light pulses of different duty cycles based on the position and/or angular velocity of the laser beam.

Abstract: A laser diode driving apparatus for optical communication is provided so as to prepare a low-price and low-power optical transmission and reception apparatus by realizing the high performance laser diode driving apparatus for optical communication with a structure appropriate for a multichannel array that can easily and effectively provide stable bandwidths and high gains of the optical communication laser diode at a transmission end of the optical transmission and reception apparatus.

Abstract: A method for monitoring a laser system including a plurality of laser modules connected in series, there being connected in parallel to each laser module a bypass arrangement for bridging the corresponding laser module, includes determining a first laser power of the laser system with a plurality of laser modules operational; activating the bypass arrangement of at least one laser module so that at least one of the plurality of laser modules is bypassed; determining a second laser power of the laser system with the at least one of the plurality of laser modules bypassed; and monitoring the laser system based on a difference between the first and second laser power.

Abstract: A laser processing apparatus, a filter device and a method are used for controlling a pulse laser, which is controllable in terms of its pulse energy and of a temporal triggering of laser pulses, during material processing of an object, in particular during the marking of a plastics-based document. The method includes comparing a pulse energy signal which assumes voltage values, in temporal correlation with a clock signal, which represent a pulse energy for the laser pulses for processing, with a threshold value condition and generating a logic result signal. The clock signal is passed to a gate and controlling the gate using the logic result signal and generating a retrieval signal thereby. An energy control signal is provided which has a voltage according to a specification of a control voltage. The retrieval signal and the energy control signal are used to control the pulse laser.

Abstract: A laser apparatus may include a master oscillator configured to output a laser beam, at least one amplifier disposed in a beam path of the laser beam from the master oscillator, at least one power source for applying a high-frequency voltage to the at least one amplifier, and a controller for varying the high-frequency voltage to be applied to the at least one amplifier from the at least one power source.

Abstract: A semiconductor laser driving device that drives a semiconductor laser with a driving current output from a driving current output terminal is disclosed. The semiconductor laser driving device includes a driving current monitoring terminal configured to output a driving current monitoring current having a value of 1/? of the driving current; a current-voltage conversion resistor connected to the driving current monitoring terminal and configured to convert the driving current monitoring current having the value of 1/? of the driving current into a corresponding driving current monitoring voltage; and a detector configured to generate a reference voltage and detect whether the corresponding driving current monitoring voltage has reached the reference voltage.

Abstract: Embodiments for driving a laser diode includes generating a bias current having a duty cycle that is less than 100%. The current level of the bias current is insufficient to turn on the laser diode. A drive current is generated and combined with the bias current to turn on the laser diode almost instantly.

Abstract: A driver device for a laser includes a control device configured to generate a control current, an NPN differential amplifier connected to the control device and configured to superimpose a modulation current onto the control current to generate a combined current, and a laser activation switch coupled to the output of the NPN differential amplifier, the laser activation switch operating the laser utilizing the combined current. Also described herein is a communication system including a driver device.

Abstract: A method to operate a semiconductor laser diode (LD) in a differential configuration is disclosed. The method first obtains the threshold current ITH in a bared LD under at least one temperature. Then, a linear relation with coefficients of ? and ? between the bias current IB and the modulation current IM independent of temperatures is evaluated by, under the operation of the APC circuit to set the bias current and under the at least one temperature, measuring at least two extinction ratios, ER1 and ER2, as varying the modulation current at two levels, IM1 and IM2. Two coefficients of ? and ? are estimated by a mathematical comparison.

Abstract: Disclosed is a method of controlling a laser apparatus, which has a laser light irradiation unit, an excitation unit including a flash lamp, a laser light shielding unit, and a control unit configured to control light shielding by the light shielding unit and release of the light shielding and control setting conditions of the flash lamp. The control unit performs a process of blocking the laser light by the light shielding unit when irradiation of the laser light is stopped, then performs a process of controlling the setting condition so that consumption of the flash lamp is reduced, performs, when the irradiation is restarted, a process of controlling the setting conditions so that the laser light is stably irradiated, and then performs a process of releasing the light shielding.

Abstract: 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 circuits for monitoring the operation state of the wavelength variable light source converge to the target values.

Abstract: A bias circuit of an electro-absorption modulated laser and a calibration method thereof are provided. The bias circuit includes a drive circuit and a direct current bias voltage circuit. The drive circuit is used for providing a forward bias voltage to a laser diode in the electro-absorption modulated laser to generate laser. The direct current bias voltage circuit is connected to a cathode of an electro-absorption modulator in the electro-absorption modulated laser, and provides a positive direct current bias voltage to the cathode to enable the reverse bias voltage of the electro-absorption modulator to fall within the range of modulation. When the reverse bias voltage falls within the range of modulation, the electro-absorption modulator utilizes the laser generated by the laser diode as optical carrier wave, modulates the optical carrier wave with the modulation voltage, and outputs a modulated optical signal.

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: A method for tuning a semiconductor laser including a plurality of wavelength selection portions, each of which has a periodic wavelength characteristic, including: controlling a value of a refractive index controlling means of the wavelength selection portions to achieve a desired output wavelength of the laser; and shifting the value when the value is equal to or excess of a predetermined value to a basal value side until achieving the desired output wavelength, the basal value being a value without applying refractive index variation by the refractive index controlling means, the predetermined value being a value for shifting one period of the periodic wavelength characteristic.

Abstract: An apparatus of automatic power control for burst mode laser transmitter and method are provided. In one implementation a method includes: generating an output current with a modulation pattern determined by a transmit data and a transmit enable signal, and a modulation level determined by a first control code and a second control code, wherein a light signal is generated in response to the output current; generating a first decision based on a comparison between a photodiode current and the first reference current, a second decision based on a comparison between the photodiode current and the second reference current, wherein the photodiode current is generated in accordance to the light signal; and generating the first control code and the second control code in response to the first decision and the second decision.

Abstract: A laser device includes: a signal light source that outputs seed light; an electro-optic modulator that chops a portion of the seed light outputted from the signal light source and outputs signal light; an optical amplifier that amplifies the signal light outputted from the electro-optic modulator; a wavelength conversion optical element that wavelength converts the signal light amplified by the optical amplifier; a converted light detector that detects the signal light that has been wavelength converted by the wavelength conversion optical element; and an EU control unit that controls the operation of the electro-optic modulator, wherein the EU control unit is adapted, in the state in which the seed light is being outputted, to adjust bias voltage of the electro-optic modulator on the basis of the applied voltage when the intensity of the signal light after wavelength conversion detected by the converted light detector becomes substantially maximum.