Abstract: A pulsed laser diode driver includes an inductor having a first terminal configured to receive a source voltage. A source capacitor has a first terminal connected to the first terminal of the inductor to provide the source voltage. A bypass switch has a drain node connected to a second terminal of the inductor and to a first terminal of a bypass capacitor. A laser diode switch has a drain node connected to the second terminal of the inductor. A laser diode has an anode connected to a source node of the laser diode switch and a cathode connected to a bias voltage node. The laser diode switch and the bypass switch control a current flow through the inductor to produce a high-current pulse through the laser diode, the high-current pulse corresponding to a peak current of a resonant waveform developed at the anode of the laser diode.

Abstract: An image display element includes micro light emitting elements disposed in an array on a driving circuit substrate. An excitation light emitting element includes a main body including a compound semiconductor, a metal electrode disposed on a side of the main body located closer to the driving circuit substrate, and a transparent electrode disposed on an opposite side to the driving circuit substrate, and a light emission layer included in the main body is disposed on a side opposite to the driving circuit substrate from a center portion of the main body.

Abstract: A pulsed laser diode driver includes multiple resonant laser diode driver cells, each cell including an inductor having a first inductor terminal to receive a source voltage, a source capacitor coupled between the first inductor terminal and ground, a bypass capacitor having a first terminal connected to the first inductor terminal and a second terminal connected to a second inductor terminal, a laser diode having a cathode that is connected to the first inductor terminal and an anode that is connected to the second inductor terminal, and a bypass switch connected between the second inductor terminal and ground. Each cell's bypass switch is configured to control a current flow through that cell's respective inductor to produce a high-current pulse through that cell's laser diode, the high-current pulse corresponding to a peak current of a resonant waveform developed at the anode of that cell's laser diode.

Abstract: A semiconductor process transport apparatus including a drive section with at least one motor, an articulated arm coupled to the drive section for driving articulation motion, a machine controller coupled to the drive section to control the at least one motor moving the articulated arm from one location to a different location, and an adapter pendant having a machine controller interface coupling the adapter pendant for input/output with the machine controller, the adapter pendant having another interface, configured for connecting a fungible smart mobile device having predetermined resident user operable device functionality characteristics, wherein the other interface has a connectivity configuration so mating of the fungible smart mobile device with the other interface automatically enables configuration of at least one of the resident user operable device functionality characteristics to define an input/output to the machine controller effecting input commands and output signals for motion control of the

Abstract: A method (900) includes a gain current (IGAIN) to an anode of a gain-section diode (D0) disposed on a shared substrate of a tunable laser (310), delivering a modulation signal to an anode of an Electro-absorption section diode (D2) disposed on the shared substrate of the tunable laser, and receiving a burst mode signal (330) indicative of a burst-on state or a burst-off state. When the burst mode signal is indicative of the burst-off state, the method includes sinking a sink current (ISINK) away from the gain current at the anode of the gain-section diode. When the burst mode signal transitions to be indicative of the burst-on state from the burst-off state, the method includes ceasing the sinking of the sink current away from the gain current and delivering an overshoot current (IOVER) to the anode of the gain-section diode.

Abstract: A method (900) includes delivering a first bias current (IGAIN) to an anode of gain-section diode (590a) and delivering a second bias current (IPH) to an anode of a phase-section diode (590b). The method also includes receiving a burst mode signal (514) indicative of a burst-on state or a burst-on state, and sinking a first sink current (ISINK) away from the first bias current when the burst mode signal is indicative of the burst-off state. When the burst mode signal transitions to be indicative of the burst-on state from the burst-off state, the method also includes sinking a second sink current away from the second bias current at the anode of the phase-section diode and ceasing the sinking of the first sink current away from the first bias current at the anode of the gain section diode.

Abstract: A ranging system includes a first ranging unit with a first laser driver, a first control circuit generating a first trigger signal, and a first data interface with a first trigger transmitter transmitting the first trigger signal over a first data transmission line and a first calibration receiver receiving a first calibration signal over a second data transmission line. A second ranging unit includes a second laser driver, a second data interface with a second trigger receiver receiving the first trigger signal and a second calibration transmitter transmitting the first calibration signal, and a second control circuit generating the first calibration signal in response to receipt of the first trigger signal. The first control circuit determines an elapsed time between transmission of the first trigger signal and receipt of the first calibration signal. The determined elapsed time is used to synchronize activation of the first and second laser drivers.

Abstract: Methods for driving a tunable laser with integrated tuning elements are disclosed. The methods can include modulating the tuning current and laser injection current such that the laser emission wavelength and output power are independently controllable. In some examples, the tuning current and laser injection current are modulated simultaneously and a wider tuning range can result. In some examples, one or both of these currents is sinusoidally modulated. In some examples, a constant output power can be achieved while tuning the emission wavelength. In some examples, the output power and tuning can follow a linear relationship. In some examples, injection current and tuning element drive waveforms necessary to achieve targeted output power and tuning waveforms can be achieved through optimization based on goodness of fit values between the targeted and actual output power and tuning waveforms.

Abstract: A waveform generator configured to generate two waveforms of opposite polarity so as to provide a voltage gain across a load. The waveform generator has a primary side circuit comprising a first inductor. The waveform generator has a secondary side circuit comprising a second inductor, a first output region conductively coupled to the load, and a second output region conductively coupled to the load. The second inductor is inductively coupled to the first inductor. The first inductor is conductively coupled to the first output region so as to supply a first of the two waveforms to the load. The second inductor is conductively coupled to the second output region so as to supply a second of the two waveforms to the load. A system incorporating the waveform generator and a method of driving the waveform generator are also provided.

Abstract: In an embodiment of the present invention, a method for controlling a voltage across a single photon avalanche diode includes: providing an output based on a current flowing through the single photon avalanche diode; and controlling the voltage applied across the single photon avalanche diode based on the provided output.

Abstract: A laser driving apparatus includes a driver, a tracking circuit, a comparator and a control circuit. The driver includes a laser driving circuit, and the tracking circuit includes a reference current source and a replica circuit. The laser driving circuit generates a driving current to drive a laser. The reference current source generates a reference current as a reference for the laser driving apparatus. The replica circuit corresponds to at least a portion of the laser driving circuit, generates a sensing current according to the reference current and track the driving current. The comparator compares voltages respectively on the laser driving circuit and the replica circuit to generate a comparison signal. The control circuit adjusts the sensing current or the driving current according to the comparison signal. The laser driving apparatus can include multiple channels with multiple drivers.

Abstract: A display system comprises a current source, pulse circuitry, a pulsed laser, control circuitry, and a display surface. The pulse circuitry outputs a first pulse of electrical current based upon electrical current emitted by the current source. The pulsed laser emits first light based upon the first pulse, wherein luminance of the first light is based upon a first amplitude of the first pulse. The control circuitry generates an estimate of pulse history effects on second light that is to be emitted by the pulsed laser, the estimate is generated based upon a parameter of the first pulse and a desired luminance of the second light. The control circuitry causes the pulse circuitry to output a second pulse of electrical current based upon the estimate. Based upon the second pulse, the pulsed laser emits second light with the desired luminance.

Abstract: A push-pull circuit for an opto-electronic device includes: an output node; a pull-up circuit that, in operation, controls a falling edge rate of an input signal to the opto-electronic device while sharing charge with the output node; and a pull-down circuit that, in operation, controls a rising edge rate of the input signal to the opto-electronic device while sharing charge with the output node.

Abstract: A micro laser diode projector comprises: an MEMS scanning device, which rotates around a first axis and a second axis that are orthogonal to each other; and a micro laser diode light source including at least one micro laser diode, wherein the micro laser diode light source is mounted on the MEMS scanning device and rotates around the first and second axes with the MEMS scanning device to project light to a projection screen. An electronics apparatus including the micro laser diode projector is also discussed.

Abstract: A laser driver with high-speed and high-current and current modulating method thereof is invented. The laser driver includes a first driving unit and a second driving unit, each driving unit including a pre-drive amplifier circuit and a main drive amplifier circuit. The pre-drive amplifier circuit includes a first differential transistor pair circuit, a differential voltage conversion circuit, a DC common mode level reduction circuit and a first cascode current mirror circuit. The main drive amplifier circuit includes a second differential transistor pair circuit, a bandwidth boost circuit, a matching circuit and a second cascode current mirror circuit. The present invention avoids the enhancement of chip area caused by the use of passive inductors peaking mode to enhance bandwidth, and reduces the cost of chip, design complexity and circuit power consumption.

Abstract: A system for surgical treatment, in particular endovenous laser treatment, includes a laser device and an application module, wherein the laser device comprises a laser light source having at least one first laser diode element and the application module is optically connectable or connected to the laser light source. The application module is designed as a flexurally flexible catheter having an optical waveguide which comprises an RFID chip with a parameter and/or release coding, wherein the laser device comprises a controlling means with an RFID transmitter and receiver unit for reading from and writing to the RFID chip. The controlling means is configured such that an activation of the laser light source ensues in response to the RFID receiver unit detecting a predetermined parameter and/or release coding, and a timestamp is stored on the RFID chip for the invalidating of the catheter.

Abstract: A circuit includes a peak detector, a diode, a dynamic clamp circuit, and an offset correction circuit. The peak detector generates a voltage on the peak detector output proportional to a lowest voltage on the peak defector input. The anode of the diode is coupled to the peak detector input. The dynamic clamp circuit is coupled to the peak detector input and is configured to clamp a voltage on the peak detector input responsive to a voltage on the diode's anode being greater than the lowest voltage on the peak detector's input. The offset correction circuit is coupled to the peak detector output and is configured to generate an output signal whose amplitude is offset from an amplitude of the peak detector output.

Abstract: A current drive circuit has a first transistor that outputs a current, a second transistor connected to the first transistor by cascode connection, a third transistor connected to the second transistor by cascode connection, a first current source that supplies a current to the third transistor and the second transistor, a fourth transistor that shares a gate with the third transistor, a fifth transistor that is connected to the fourth transistor by cascode connection and shares a gate with the second transistor, a second current source that supplies a current to the fourth transistor and the fifth transistor, a sixth transistor that shares a gate with the third transistor and the fourth transistor and controls a gate voltage of the first transistor, and a third current source that supplies a drain current of the sixth transistor.

Abstract: A droplet timing sensor that detects droplet passage timing by receiving a light from a light source unit with which a droplet is irradiated in an extreme ultraviolet light generating apparatus eliminates an influence of droplet passage on light source control for obtaining a constant light income. The droplet timing sensor includes: a light source unit configured to irradiate a droplet with an illumination light at a predetermined position; a light receiving unit (70) configured to receive the illumination light having passed through the predetermined position and detect a change in a light income; and a light source controller (301) configured to obtain a frequency distribution of light incomes measured multiple times with time using a statistical processing unit (76), and control an output of the light source unit based on a light income at maximum frequency.

Abstract: A semiconductor device includes a substrate including a resistor region, a plurality of lower patterns in the resistor region, and a resistor line pattern on the plurality of lower patterns and the substrate of the resistor region. The plurality of lower patterns extend in a first direction parallel to a surface of the substrate and are spaced apart from each other in a second direction perpendicular to the first direction and parallel to the surface of the substrate. The resistor line pattern extends in the second direction. The resistor line pattern on the lower patterns has an upper surface and a lower surface protruding in a third direction perpendicular to the surface of the substrate.

Abstract: This invention provides an accurate current mirror circuit in a low voltage headroom applied to common-anode laser drivers, including a reference current detection unit, a tail current source unit, and a control unit. The reference current detection unit generates a bias voltage and a reference voltage according to a reference current from the reference current source; the tail current source unit receives the bias voltage and generate a mirror current accordingly; the control unit receives the reference voltage and an output voltage corresponding to the mirror current and carry out a feedback regulation to the bias voltage accordingly. In this invention, the reference voltage and the output voltage are locked at same level, and then the bias voltage is mirrored to generate the mirror current outputted to the laser, thus avoiding the problem of inaccurate current output caused by the offset of the control unit in the low voltage headroom.

Abstract: A beacon system includes a controller, a laser module operably connected to the controller, and at least one sensor operably connected to the controller. In such a system, the controller is configured to receive a signal from the at least one sensor, and to determine whether a response to the signal is required.

Abstract: A controller includes an amplification ratio control unit, an amplification unit, a digital conversion unit, and a driving current control unit. The amplification ratio control unit is configured to generate an amplification ratio signal based on an ambient temperature of a laser diode. The amplification unit configured to amplify, based on the amplification ratio signal, a detection current from a photodiode configured to detect light output from the laser diode, and output the detection current as a voltage signal. The amplification ratio signal controls an amplification ratio of the amplification unit. The digital conversion unit is configured to convert the voltage signal into a digital signal. The driving current control unit is configured to control a driving current of a driver configured to drive the laser diode based on the digital signal.

Abstract: A driver for driving laser or a modulator comprises a switch block for switching a current to the laser or modulator and a voltage converter comprising a voltage supply node, an input port for connecting a laser or modulator supply voltage and an output port connected to the switch block. The voltage converter comprises a voltage replica block adapted for generating a pre-defined voltage and is adapted for equalizing DC voltages in the driver by using the pre-defined voltage. The pre-defined voltage approximates the threshold voltage drop of a laser when the driver is connected with a laser or approximates the bias voltage over a modulator when connected with a modulator. The driver comprises a balancer comprising a dummy load connected to the switch block adapted for equalizing voltages in the switch block.

Abstract: A modulated light source comprises a laser diode and a drive circuit coupled operatively to the laser diode. The laser diode is configured to lase upon passing an above-threshold current for an accumulation period. The drive circuit is configured to draw a priming current through the laser diode over a priming period, the priming current being insufficient to cause the laser diode to lase during the priming period, but sufficient to shorten the accumulation period. The drive circuit is further configured to draw the above-threshold current through the laser diode after the priming period, thereby triggering emission from the laser diode following a shortened accumulation period.

Abstract: A CMOS IR transceiver includes an IR transmitter circuit, an IR receiver circuit, and an IR diode configured to either emit or receive an IR signal. CMOS elements, such as a PMOS current mirror, a PMOS switch, a NMOS switch, a NMOS current mirror, and a receiver enabling PMOSFET switch are used in the CMOS IR transceiver. The CMOS IR transceiver may have advantages of increased integration, occupying less space, and lower cost.

Abstract: An optical module includes a laser transmitter driver chip, a Distributed Bragg reflection (DBR) raster, a laser transmitter, a first resistor, a first capacitor, a second resistor, a second capacitor and a power source. The first resistor is connected between a power source and a differential signal output positive terminal of the laser transmitter; the first capacitor is connected between the differential signal output positive terminal and the a positive terminal of the laser transmitter; the second resistor is connected between the power source and a differential signal output negative terminal of the laser transmitter driver chip; the second capacitor is connected between the differential signal output negative terminal and a negative terminal of the laser transmitter; and the negative terminal of the laser transmitter and a negative terminal of the DBR raster are grounded.

Abstract: The present disclosure is generally directed to a laser subassembly for use in a TOSA module that includes an integrated impedance matching network to enable a plurality of selectable resistance configurations to ensure the driving circuit and laser emitter of the TOSA module have matching, or substantially matching, impedances. The laser subassembly includes a substrate with a driving circuit disposed thereon. The driving circuit includes signal conductors for electrically coupling to an external transmit connecting circuit, a conductive laser mounting section, and an impedance matching network. The impedance matching network includes a plurality of resistors, with one or more of the resistors being selectively electrically coupled to the conductive laser mounting section to introduce a selected amount of impedance to minimize or otherwise reduce reflection.

Abstract: A driver circuit for driving a laser diode is described herein. In accordance with a first exemplary embodiment the driver circuit includes a first electronic switch connected to an output node that is configured to be operably connected to a laser diode. The electric connection between the first electronic switch and the output node has a first inductance. The driver circuit further includes a bypass circuit that is coupled to the output node and configured to take over, when activated, the current supplied to the output node via the first electronic switch, thus magnetizing the first inductance.

Abstract: The present disclosure is directed to an optical device including at least one temperature-dependent tunable element for controlling a wavelength of an optical signal, a first temperature control circuit for controlling a temperature of a first region of the optical device; and a second temperature control circuit for controlling a temperature of a second region of the optical device. The second region may include a portion of the first region. The second region may be smaller than the first region. The tunable element may be positioned in the second region such that a temperature of the tunable element is controlled based on the second temperature control circuit controlling the temperature of the second region. The tunable element may be one of (i) a laser for transmitting an outgoing optical signal and (ii) an optical filter coupled to a photodetector for receiving an incoming optical signal.

Abstract: An integrated high speed electro-optical control loop for very high-speed linearization and temperature compensation of an electro-absorption modulator (EAM) for analog optical data center interconnect applications is disclosed. The control loop can function in a stable manner because the electronics and optical components are monolithically integrated on a single substrate in small form factor. Because of the small size enabled by monolithic integration, the temperatures of the optical blocks and electronics blocks are tightly coupled, and the control loop time delays and phase delays are small enough to be stable, even for very high frequency operation. This arrangement enables a low cost, low power analog transmitter implementation for data center optical interconnect applications using advanced modulation schemes, such as PAM-4 and DP-QPSK.

Abstract: Systems and methods for calibrating, operating, and setting the magnitude of the power of light provided by a laser diode in a conducted electrical weapon (“CEW”). The light of the laser diode assists in targeting by providing a visible indication of the projected point of impact of the tethered electrode of the CEW. The calibration process enables laser diode of a CEW to operate within regional guidelines of the maximum output power of light permitted by a laser. The method further permits the magnitude of the power of the light provided by a laser diode to be set and operated in changing environmental conditions in the field.

Abstract: A battery-powered laser-based dermatological treatment device may include a laser unit comprising at least one laser diode, a battery unit, at least one sensor configured to generate sensor signals, and a laser drive control system including a laser drive circuit comprising the laser unit, the battery unit, a first switch (e.g., a first FET), and a second switch (e.g., a second FET), wherein the laser unit is arranged in series between the first switch and the second switch, and control electronics configured to control the first switch based at least on sensor signals from the at least one sensor, and control the second switch using pulse width modulation (PWM), thereby delivering current from the battery unit to the laser unit with a PWM current waveform. The laser drive circuit may also include a snubber circuit configured to prevent voltage spikes upon the second switch being turned off.

Abstract: A method for biasing a tunable laser during burst-on and burst-off states through a common-cathode laser driving circuit includes delivering a bias current to an anode of a gain-section diode having a shared substrate with the laser, and receiving a burst mode signal indicative of a burst-on state or a burst-off state. When the burst mode signal is indicative of the burst-off state, the method includes sinking a sink current away from the anode of the gain-section diode. The sink current is less than the bias current delivered to the anode of the gain-section diode. When the burst mode signal transitions to be indicative of the burst-on state from the burst-off state, the method includes ceasing the sinking of the sink current away from the anode of the gain-section diode, and delivering an overshoot current to the anode of the gain-section diode to accelerate heating of the gain-section diode.

Abstract: An optical module that includes at least one semiconductor optical device, a carrier, a housing, and eutectic alloy that fixes the carrier to the housing is disclosed. The carrier mounts a component that couples with the semiconductor optical device. The housing, which includes a side wall made of ceramics and a base made of metal to form a space that encloses the semiconductor optical device, the carrier, and the component therein. The carrier provides a room facing the base and the side wall, where the room receives excess eutectic alloy oozing out from a gap between the carrier and the base.

Abstract: A light source apparatus includes at least one light-emitter, a driving circuit, an input unit, a temperature control circuit, and an effective light power setting circuit. The driving circuit allows the light-emitter to emit light by applying a driving waveform to the light-emitter. The effective light power setting circuit drives the driving circuit to allow the light-emitter to emit light with a predetermined effective light power, in accordance with a driving condition set by the temperature control circuit. The temperature control circuit controls the light-emitter to be in a predetermined heat generation state by increasing or decreasing a heat generation amount of the light-emitter without changing the predetermined effective light power of the light emitted from the light-emitter by adjusting the driving condition of the light-emitter.

Abstract: Provided is a technology for suppressing variations in the waveform of a light emission pulse caused by various factors in a light-emitting device. A light-emitting device is provided with: a light source 101 in which relaxation oscillation occurs immediately after energization; a light source drive circuit 104 which includes a differentiation circuit 102 having a resistor and a capacitor connected in parallel, and in which a switching element 103 for voltage application is connected in series with the differentiation circuit; a power supply circuit 105; a light-reception element 107 which detects pulsed light emitted from the light source 101; and a voltage control unit 109 which controls an output voltage from the power supply circuit 105 in correspondence with the waveform of the detected pulsed light.

Abstract: Excimer laser annealing apparatus includes and excimer laser delivering laser-radiation pulses to a silicon layer supported on a substrate translated with respect to the laser pulses such that the consecutive pulses overlap on the substrate. The energy of each of the laser-radiation pulses is monitored, transmitted to control-electronics, and the energy of a next laser pulse is adjusted by a high-pass digital filter.

Abstract: A semiconductor laser driving circuit that ensures the satisfied extinction ratio, the accuracy of the light output, and enables the light output dynamically to change based on a modulation signal.

Abstract: A controllable current driver integrated circuit is provided. The controllable current driver includes a multitude of different current value output transistors digitally controlled and combined to provide a controllable current output. The different current value transistors are each provided as single lithographic devices on a same substrate in proximity to each other having weighted drain and source areas corresponding to the different current values. The weighted drivers reduce the implementation area required on the semiconductor die for decoding and driving the output transistors substantially increasing the density of current drivers which can be integrated in one semiconductor die.

Abstract: Non-ideal downstream loading of a differential driver in a single ended circuit driving a communications laser—e.g., Electro absorption Modulated Laser (EML)—may be compensated by deploying a second matching network at the non-functional (terminated) driver output node. Certain embodiments may further compensate for distortion arising from circuit non-ideality, by introducing a laser replica downstream of the second matching network to mimic electrical properties of the laser. Embodiments may sufficiently compensate for downstream circuit non-ideality to allow replacing the bulky choke inductor of a bias tee, with a resistor. Substituting a resistor for a more complex inductor structure can simplify design and fabrication of the single-ended driver circuit, and also reduce footprint by eliminating area formerly occupied by the choke inductor.

Abstract: An imaging device has a photoconductor with a surface that is selectively discharged by a light from a laser diode to create a latent electrostatic image for attracting toner for transfer to a media. A circuit drives the laser diode. The circuit has a switch for turning on and off the light, a resistor complementary to the laser diode selectively connectable to the switch, and a passive circuit component coupled to the laser diode. The passive circuit component is a delay line, inductor, choke, coiled wire, or ferrite bead is contemplated. It may also typify a length of copper tracing on a printed circuit board that supports the laser diode. The circuit causes an initial overshoot voltage spike in an on voltage pulse that is about 20% or more than the settled on voltage. The voltage spike dampens out in about one-fourth of a total voltage on time of the pulse.

Abstract: An optical module includes a laser transmitter driver chip, a Distributed Bragg reflection (DBR) raster, a laser transmitter, a first resistor, a first capacitor, a second resistor, a second capacitor and a power source. The first resistor is connected between a power source and a differential signal output positive terminal of the laser transmitter; the first capacitor is connected between the differential signal output positive terminal and the a positive terminal of the laser transmitter; the second resistor is connected between the power source and a differential signal output negative terminal of the laser transmitter driver chip; the second capacitor is connected between the differential signal output negative terminal and a negative terminal of the laser transmitter; and the negative terminal of the laser transmitter and a negative terminal of the DBR raster are grounded.

Abstract: According to the invention, a plurality of elementary laser beams (fi) are generated, the phases of which are adjusted by an electro-optical feedback loop (6, 7i, 8i, 9) implementing the matrix equation of a phase-contrast filtering device (6).

Abstract: A light scanning apparatus, including: a light source configured to emit a light beam; a light intensity detection portion configured to detect a light intensity of the light beam; and a light intensity control portion configured to control the light intensity of the light beam based on a detection result of the light intensity detection portion, wherein the light intensity control portion supplies, in advance, to the light source, a bias current equal to or less than a threshold current at which the light source starts emitting the light beam, and supplies, to the light source, a switching current superposed on the bias current, the switching current being modulated in order to control light emission of the light source in accordance with an image signal, and wherein the light intensity control portion includes a bias current changing unit configured to change the bias current.

Abstract: Systems and methods described herein include methods and systems for controlling bias voltage provided to an optical modulating device. The optical modulating device is biased at a bias point that is different from a null point of the device such that an offset to the received optical power due to limited extinction ratio is reduced.

Abstract: A drive circuit includes a bias current supply circuit for supplying a bias current to a light-emitting element and a modulated current supply circuit for supplying a modulated current to the light-emitting element, and has a first path through which the bias current flows, a second path including a path for supplying the modulated current to the light-emitting element from the modulated current supply circuit, through which a current returns to the bias current supply circuit through the modulated current supply circuit from the bias current supply circuit without going through the light-emitting element when the bias current flows, and a third path which is joined to the second path in the modulated current supply circuit and has an adjusting resistance before a junction, through which a current flows through the adjusting resistance to the bias current supply circuit when the bias current flows.

Abstract: A driving circuit for causing a light emitting element to emit light in response to a driving signal is provided. The driving circuit comprising a first current supply circuit that starts to supply a driving current to the light emitting element in response to the driving signal, a second current supply circuit that starts to supply a supplementary current to the light emitting element in response to the driving signal. The second current supply circuit stops to supply the supplementary current upon detecting that a voltage applied to the light emitting element has reached a threshold voltage.

Abstract: A laser diode driving method that reliably maintains average optical power and extinction ratio is disclosed. The present invention for laser driving uses a preloaded laser diode characteristic curve/table and/or mathematical equations to create a programmable bias and modulation current range. This ensures stable closed-loop operation and prevents system failure if the feedback signal is impaired by confining the operation of the laser diode to a normal operating range.

Abstract: A light scanning apparatus, including: a light source configured to emit a light beam; a rotary polygon mirror configured to deflect the light beam emitted from the light source so that the light beam scans on a surface of a photosensitive member in a main scanning direction; a motor configured to rotate the rotary polygon mirror; and a rotational position detection unit configured to detect a magnetic flux change caused by rotation of the motor to generate a rotational position detection signal, wherein an emitting start timing of the light beam from the light source is determined based on the rotational position detection signal in order to maintain a writing start position of the light beam with respect to the photosensitive member in the main scanning direction.