Abstract: Various embodiments of a multi-laser system are disclosed. In some embodiments, the multi-laser system includes a plurality of lasers, a plurality of laser beams, a beam positioning system, beam focusing optics, a thermally stable enclosure and a temperature controller. The thermally stable enclosure is configured to thermally and mechanically couple to a flow cell. The thermally stable enclosure substantially comprises a material with high thermal conductivity. The thermally stable enclosure can have a relatively small volume.

Abstract: The invention describes the method and apparatus for enhancement of coupling efficiency in effective-ridge laterally-coupled surface-etched grating waveguide structures, where a slab waveguide has a sequence of the periodic parallel segmented trenches etched from its top surface, such that the segments of intact material having higher refractive index than that in the surrounding segments of periodic trenches form the effective ridges which confine the optical field in and around these ridges, on one hand, and provide bidirectional coupling for the confined modes experiencing Bragg reflection from the segments of the periodic trenches, on the other.

Abstract: Laser power control arrangements interrupt power to a laser used in electro-optical readers upon detection of an over-power condition not conforming to preestablished regulatory standards. In one embodiment, during an operational mode, a difference between laser drive currents at two operating points is compared to a difference between laser drive currents at the same two operating points during a calibration mode. The over-power condition is recognized when the difference during the operational mode exceeds the difference during the calibration mode by a predetermined amount. In another embodiment, the laser is only energized to emit the beam at a reduced power level well below regulatory standards for staring at even if a motor drive failed.

Abstract: The invention is directed to a laser diode assembly having a laser diode and a support, whereon the laser diode is arranged or formed in one single piece. The laser diode assembly further includes a coupling capacitor integral therewith, wherein the laser diode is subjected to the action of a laser driver circuit via the coupling capacitor associated with the assembly. The invention is also directed to a device for operating a laser diode, wherein the device includes a coupling capacitor integral with a laser diode assembly. The invention enables a reduction in the number of coupling paths between a laser driver circuit and a laser diode assembly, thereby reducing the occurrence of parasitic elements.

Abstract: Techniques and devices to stabilize a passively mode-locked laser against the timing jitter by using a feedback control signal based on a signal component at a high harmonic frequency of the laser pulse repetition frequency in the laser output to control the optical path length of the laser resonator.

Abstract: The invention relates to a method for initializing a control of a supply voltage of a light source, such as a laser diode, the light source being arranged in a first circuit configuration having an associated first reference voltage level or the light source being arranged in an alternative second circuit configuration having an associated alternative second reference voltage level, the method comprising the steps of gradually changing the supply voltage into the direction of the first reference voltage, measuring a light emission of the light source while gradually changing the supply voltage, if no light emission is measured: starting the control of the supply voltage of the light source after the first reference voltage has been reached and if a light emission is measured gradually changing the supply voltage into the direction of the second reference voltage and starting the control of the supply voltage of the light source after the second reference voltage has been reached.

Abstract: A laser noise elimination circuit raises the gain of a first TIA and at the same time reflected light from an optical disc of a laser beam is subjected to photoelectric conversion by means of a photo detector and a second TIA to obtain an RF signal. Then, the direct current component of the FPD signal obtained by photoelectric conversion of part of the laser beam by means of another photo detector and the first TIA is cut out by a high pass filter and then subtracted by a subtracter. The gain of the first TIA is raised in a read mode of operation for reading data from the optical disc and lowered in a write mode of operation for writing data onto the optical disc so as to always effectively eliminate only the laser noise from the RF signal and prevent the circuit from being saturated in a write mode.

Abstract: An inexpensive laser drive device which is capable of driving a laser for emission of an appropriate amount of light. Electric currents supplied from a supply current control device formed in an integrated circuit to a plurality of predetermined ports of the integrated circuit are turned on and off by switching devices in response to a signal from a signal output device of the supply current control device, and the on currents are supplied, as a driving current, from the supply current control device to a laser beam-emitting device through corresponding ones of the predetermined ports and resistors externally attached to these ports. A generator device formed in the integrated circuit generates a pulse signal for turning on and off a laser beam based on image data.

Abstract: A laser diode module with an adjustable monitoring current, wherein the photo diodes monitoring the light-emitting power of the laser diode are arranged in array, and wherein a programmed photo diode is formed by the photo diodes in match of a memory and switch control unit. In this way, the problem of an inconstant monitoring current of the prior art is avoided. Meanwhile, an adjustable monitoring current is achieved.

Abstract: According to various illustrative embodiments, a device, method, and system for measuring optical fine structure of lateral modes of an optical cavity are described. In one aspect, the device comprises at least one photodetector arranged to detect an output of the optical cavity in a lateral direction thereof. The device also comprises an analyzer coupled to an output of the at least one photodetector and arranged to analyze at least a portion of signals produced in the at least one photodetector by at least a portion of the lateral modes of the optical cavity. The device also comprises a processor arranged to determine the optical fine structure of the at least the portion of the lateral modes of the optical cavity based on an output of the analyzer.

Abstract: A semiconductor laser driving unit is disclosed that includes a first part generating a bias current; a second part generating a first current for causing the semiconductor laser to emit light, and outputting the first current to the semiconductor laser in accordance with an input control signal; a third part performing initialization to detect a light emission characteristic of the semiconductor laser, and causing the second part to generate a second current of a value obtained from the detected light emission characteristic; and a fourth part causing the second part to generate the first current in which a set offset current is added to the second current. The first part detects the amount of light emission of the semiconductor laser, and generates and outputs the bias current so that the amount of light emission produced by the sum of the bias current and the first current is a predetermined value.

Abstract: In an optical control apparatus, a semiconductor laser emits a laser beam having a power corresponding to an energizing current. A light power detecting device detects a light power of the laser beam. A monitor voltage generating device generates a monitor voltage set based on the light power. A reference voltage generating device generates a reference voltage set based on a target light power of the laser beam. A current control device controls the energizing current such that the monitor voltage approaches the reference voltage based on a deviation of the monitor voltage from the reference voltage. A pseudo voltage input device inputs a predetermined pseudo voltage to the current control device instead of the monitor voltage under a predetermined condition such that a variation range of the deviation lies within a predetermined range.

Abstract: The invention discloses an optical transmission module with digital adjustment and method thereof. The module includes a laser (21), a laser driver (22), an automatic power adjustment circuit (23), an automatic temperature adjustment circuit (24), a digital adjustment circuit (25) and a memory (26). The digital adjustment circuit, consisted of a digital-to-analog converter or a digital adjustment potentiometer, receives a digital adjustment signal and outputs, respectively, a extinction ratio adjustment signal and a cross point adjustment signal to the laser driver, an optical power adjustment signal to the automatic power adjustment circuit and an optical wavelength adjustment signal to the automatic temperature adjustment circuit. The memory stores data, using for on-line adjustment of the optical transmission module, at least including parameters of said optical transmission module and said laser emitting optical power parameters, to be reported upward.

Abstract: An auxiliary component such as a bias inductance (6) associated with a laser source (2) is mounted generally “upright”, that is with its major dimension substantially orthogonal to the general plane of the submount (S) supporting both the laser (2) and the auxiliary component (6). The inductor (6) is preferably mounted at a location displaced laterally with respect to the lasing direction (X) of the laser source. The arrangement preferably includes a submount (S) with a recess (13) and at least part of the laser driver is arranged in the recess so that the driver (3) has an end surface extending from the recess substantially flush with the pad (12) for mounting the laser source. The arrangement minimises surface occupation as well as RF and EMI parasitic effects related to wirebonding.

Abstract: In a laser power control apparatus for controlling a laser power of a combination drive, first laser light Lc applied onto a first optical disk and second laser light Ld applied onto a second optical disk is collected by one photodetector 8.

Abstract: A light transmitter and an auto-control circuit thereof are provided. The circuit includes a driving module and a feedback module. The driving module is coupled to the feedback module and a load. The driving module provides a driving current for driving the load. The feedback module provides a bias signal to the driving module according to the change of the temperature, for adjusting the driving current and stabilizing an output power.

Abstract: A laser-drive-current control circuit outputs a drive current indicating signal for indicating a laser drive current for driving a laser light emitting element that emits a laser beam to an optical disk and controls the output of the laser drive current based on a light emission monitor signal.

Abstract: The invention describes the method and apparatus for enhanced efficiency in a laterally-coupled distributed feedback (LC-DFB) laser. In a device featuring the effective ridge design, lateral confinement of the guided optical modes is provided by a surface etched grating, which also serves as a DFB element of the laser. Coupling and quantum efficiency of such a LC-DFB laser both improve with an increase of the lateral mode order. In accordance with this invention, a dramatic enhancement of the laser efficiency is achievable by designing it to operate in one of the higher order modes, notably the first order mode, while all the other lateral modes, including the zero order mode, are suppressed through gain-loss discrimination.

Abstract: In case of driving each of light emitting parts of a surface emitting laser, each of light emitting parts is made to be in forward-bias state and switches appropriately change bias voltage, which is lower than laser oscillation threshold voltage, and drive voltages, which are not less than the laser oscillation threshold voltage to directly apply the changed voltage to each of drive ends of the light emitting parts. Whereby, each of light emitting parts is driven.

Abstract: A laser power control circuit that is constituted by CMOS transistors reduces variations in a laser power that is emitted from a semiconductor laser, which are caused by a mismatch of the transistors. An offset amount of a differential amplifier is digitally calculated using an A/D converter that is located on the same chip, and a voltage value of a variable voltage source is controlled for applying a voltage in a direction opposite to the offset voltage of the differential amplifier to correct the offset voltage of the laser power control circuit, thereby reducing the variations in the laser power emitted from the semiconductor laser.

Abstract: An apparatus and method to safely control the power output of a laser source. A power monitor is optically coupled to monitor a power output of laser source generating an optical signal. The power monitor is coupled to generate power feedback data indicative of the power output. A processor is coupled to control the power output of the laser source in real-time in response to the power feedback data from the power monitor.

Abstract: Circuitry for reliably regulating the current driving a laser diode or other current-driven load is described. In particular, a dual-current driver circuit is described that uses both a current source circuit and a current sink circuit. The current source circuit and the current sink circuit may each independently control the laser diode drive current within a desired operating tolerance. The current driving the laser diode will be maintained within tolerance despite the failure of either the current source circuit or the current sink circuit. This is because the current source circuit and the current sink circuit are combined with the laser diode in series, such that the current driving the laser diode will be controlled at the lower of the two currents driven by the current source circuit and the current sink circuit.

Abstract: A laser driver IC has an RS flip-flop for latching a signal that indicates an event of fault detection, to output it as an internal fault signal, and a fault signal processing section for generating a disable signal for inactivating the driving function of the laser driver IC in response to output of the RS flip-flop. One of outputs of the fault signal processing section is connected to a fault signal output terminal linked to outside the laser driver IC.

Abstract: A semiconductor optical amplifier, an acousto-optic tunable filter, a phase shifter, a lens, and an internal etalon are arranged in a resonator. Outside the resonator, two lenses, two beam splitters, two photo-detectors, and an external etalon are arranged. The internal etalon is a quartz etalon and the external etalon is a crystal etalon. Therefore, the rate of change in transmission peak wavelength of the internal etalon to a temperature change is greater than that of the external etalon.

Abstract: One aspect of the present invention can include a laser light output control apparatus having a plurality of laser light output control systems including a laser light source capable of receiving supplying of current via a power supplying path from a power source and irradiating laser light, a photo-detecting device capable of receiving the light irradiated from the laser light source and outputting a monitor current dependent on the amount of light received, a conversion circuit capable of converting the monitor current into a voltage value, a control circuit capable of controlling the current supplied to the laser light source based on the voltage value outputted from the conversion circuit so that the intensity of laser light irradiated from the laser light source changes to a predetermined value, the respective conversion circuits of each said output control system have a fixed resistor and a variable resistor connected in series to each other, and at least one of the fixed resistors of each said pluralit

Abstract: The present invention provides a compact analog directly modulated laser configuration that is suitable for use in the field that uses electrical feedback to compensate for non-linearity in real time, such that no matter how the LI curve changes, the electrical feedback compensates for non-linearity by amplifying a portion of the output analog optical signal and combining it with the input analog electrical signal using the standard control method of negative feedback. When the gain of the feedback loop is relatively high, the overall transfer function of the system is primarily dependent on the feedback loop gain block, which is substantially linear. This is accomplished by incorporating a relatively large bandwidth photo-detector at the back facet of the laser that both monitors the output power of the system and provides a feedback signal to the linearization control circuit, as well as an amplifier.

Abstract: Both a system and method are provided for modulating the intensity of an output beam generated by semiconductor laser. The exemplary system includes a source of pulsating current connected to the laser that generates a pulsating beam of laser light, an external modulator having an input that receives the pulsating beam, and an output controlled by pulsating control signal, wherein the output beam transmitted by the external modulator output is modulated by changing a relative phase angle between the pulsating current powering the laser, and the control signal of the external modulator over time. The external modulator may be an intensity-type modulator whose output is controlled by a gate signal having a constant phase, and the source of pulsating current powering the laser may be variable phase in order to modulate the output beam with an external modulator having a simple structure.

Abstract: A package for a laser diode component is described. This comprises a carrier, which has on a front side a mounting region for a laser diode chip or laser diode bar, and at least one holding device, which is arranged on the carrier and has at least one aperture, in which an electrical terminal conductor is held. The holding device is designed for surface mounting. Moreover, a laser diode component with such a package and a method for producing a laser diode component are described. In the method, preferably a plurality of carriers are provided together in an interconnected assembly and are loaded with laser diodes. Subsequently, holding devices each with at least one electrical terminal conductor are fitted on the carriers.

Abstract: Embodiments of the invention are directed to an atomic-based frequency reference that includes an architecture that eliminates the need for local oscillator components and instead is implemented with a “photonic local oscillator,” that provides for a relatively low power consumption, compact, atomic clock/frequency reference. Such a system is based on a laser cavity which contains an alkali-vapor-cell within the laser cavity. The laser cavity is designed to oscillate in two or more optical wavelengths, with the frequency difference of these lasing wavelengths equal to the atomic hyperfine resonance frequency. Embodiments of the system can include relatively few elements, namely: a) an optical gain element with an emission band centered at the atomic absorption band; b) collimating optics; c) an atomic vapor cell; and d) a cavity end mirror. Optionally, specific polarization optics may be used depending on the specifics of the optical pumping.

Abstract: An optical disk apparatus uses a laser driver which can measure the frequency of the high-frequency superimposed current of the semiconductor laser simply and accurately. The apparatus includes a semiconductor laser which emits a laser beam onto the optical disk, a laser driver which drives the semiconductor laser with a current, with the high-frequency current being superimposed thereon, and measures the frequency of the high-frequency current, and a main controller which controls the frequency of the high-frequency current produced by the laser driver by using the frequency measured by the laser driver.

Abstract: A laser diode driver circuit includes: a current source for generating a laser drive current which drives a laser diode; a switch for switching the passage/non-passage of the laser drive current into the laser diode; an APC circuit for controlling the magnitude of the laser drive current such that the optical output power of the laser diode is equal to a predetermined value; a switch control circuit for controlling the operation of the switch according to an input signal; and a ringing suppression circuit connected to an output terminal through which the laser drive current is supplied to the laser diode, the filter circuit having a variable time constant. Herein, the switch control circuit and the ringing suppression circuit respectively switch the drive power to the switch and the time constant in conjunction with the control of the magnitude of the laser drive current by the APC circuit.

Abstract: The bias current of a current injection-type light-emitting element is set very close to the threshold current, and to guarantee a stable optical output and high-speed initiation of the light-emitting operation. In the bias current supply circuit 12, particularly in closed-loop circuit 20, feedback operation of bias APC with variable bias current Ib is performed so that monitor voltage VM1 comes to equal reference voltage VA1. With this feedback operation, the steady state of VM1=VA1 is reached, and drive current Ib (Iba+Ibb) sent to laser diode 10 converges to a constant value. After a prescribed time, S/H circuit 34 is switched to hold mode. As a result, drive current Ib (Iba+Ibb) is temporarily held to a constant value corresponding to the prescribed optical output.

Abstract: A method and apparatus to automatically control an output power of a laser diode, include generating an error voltage between an output voltage of the laser diode sampled during an automatic power control period and a reference voltage, and performing proportional-integral processing on the error voltage to generate a compensated control voltage and applying the compensated control voltage to the laser diode.

Abstract: A laser driver circuit driving a laser diode to generate an optical output corresponding to an input data, and controlling the optical output based on an output current from a photodiode that detects the optical output. The output current is converted into a voltage signal, whose amplitude is detected after filtering the voltage signal by a low-pass filter. A reference signal corresponding to the input data is generated, and its amplitude is detected. A modulator for generating a modulation current regulates the amplitude of the modulation current according to the difference between the two detected amplitudes.

Abstract: In one example configuration, an optical package includes a substrate that supports a laser. The laser is configured for electrical communication with circuitry disposed on the substrate, and the laser is arranged to emit an optical signal along a first path. The optical package also includes a beam steering device supported by the substrate and arranged so as to receive the optical signal from the laser along the first path. The beam steering device is configured such that the optical signal is output from the beam steering device along a second path. A group of electronic leads is provided that electronically communicates with the circuitry on the substrate. In this example, the group includes a set of modulation leads in electrical communication with the laser, and a set of bias leads in electrical communication with the laser. The set of bias leads is electrically isolated from the set of modulation leads.

Abstract: An automatic power control filter circuit that outputs a signal corrected to make a laser drive current for driving a laser light emitting element irradiating an optical disc with a laser beam become a desired value, on the basis of a signal obtained by sampling and holding a light emission monitor signal corresponding to an output current of a photodetector for detecting output power of the laser light emitting element.

Abstract: The temperature of a laser diode changes in response to video content across a line of a displayed image, and the radiance changes as a function of temperature. An adaptive model estimates the temperature of the laser diode based on prior drive current values. For each displayed pixel, diode drive current is determined from the estimated diode temperature and a desired radiance value. A feedback circuit periodically measures the actual temperature and updates the adaptive model.

Abstract: Optical switches and logic devices comprising microstructure-doped nanocavity lasers are described. These switches and logic devices have gain and thus can be cascaded and integrated in a network or system such as for example on a chip. Exemplary switching elements switch the intensity, wavelength, or direction of the output. Exemplary logic devices include AND, OR, NAND, NOR, NOT, and XOR gates as well as flip-flops. Microfluidic sorting and delivery as well as optical tweezing and trapping may be employed to select and position a light emitter in a nanooptical cavity to form the nanolaser.

Abstract: An apparatus and method of controlling emission of a laser beam in an image forming apparatus. The method includes generating a first reference voltage and a second reference voltage corresponding to a normal mode and a toner save mode, supplying one of the first reference voltage and the second reference voltage corresponding to a mode selection signal in a switching manner, generating a first control voltage and second control voltage to control emission of the laser beam, and supplying a drive current corresponding to one of the generated first and second control voltages to a laser diode to control intensity of the laser beam according to the selection mode.

Abstract: A transmitting and receiving device, in which the received signal which is produced by the receiving device has only a small amount of crosstalk. This object is achieved by providing a transmitting and receiving device having a transmitting device for producing a transmission signal, a receiving device for producing a received signal, and a compensation device which is connected to the transmitting device and to the receiving device and which at least reduces any crosstalk which is produced by the transmitting device in the receiving device.

Abstract: A laser diode driver circuit can comprise fast loop portion and a closed-loop portion. The closed-loop driver portion can provide a part of the current for a laser diode. The closed-loop drive portion output can be independent of a photodetector. The fast-loop driver portion can provide a second part of the current for the laser diode. The fast-loop driver portion can use the output of the photodiode to determine the output of the fast-loop driver portion.

Abstract: Various systems and methods are provided for biasing a laser. In one example, a feedback circuit establishes a bias current in a laser. A stabilizing capacitor is coupled to the feedback circuit, the stabilizing capacitor slowing the response of the feedback circuit to a feedback input. A capacitor charging circuit is included in the feedback circuit. The capacitor charging circuit is activated upon a start-up of the feedback circuit to charge the stabilizing capacitor. Thereafter, the capacitor charging circuit is deactivated when a charge on the stabilizing capacitor reaches a predefined charge threshold.

Abstract: A high-power laser system includes a laser master oscillator, a plurality of fiber laser amplifiers producing intermediate output beamlets, a diffractive optical element for combining the intermediate beamlets into a combined output beam, and one or more error controllers for minimizing errors related to beam combination that may degrade the quality of the combined output beam. A piston error controller uses phase modulation to tag each non-reference intermediate beamlet with a unique dither signal harmonically unrelated to those used for the other beamlets. For each intermediate beamlet, the associated piston error is recovered using a synchronous detector, and an error control signal proportional to the piston error is supplied to a phase modulator to control the piston error for that beamlet. A tilt error controller uses amplitude modulation based on Hadamard code words to tag each non-reference intermediate beamlet with a unique code sequence orthogonal to those used for the other beamlets.

Abstract: A laser unit having a preparatory function for activating the unit and an activation method for the unit, capable of stabilizing the temperature of each component of the laser unit in the preparation stage when the laser unit is activated in a low-temperature or high-temperature environment, and then effectively judging completion of the preparation. During a period of time Ta from T1 to T2, a first trial of laser oscillation is performed. After a period of time Tb in which the laser is not oscillated, a second trial of laser oscillation from T3 to T4. Such an operation is repeated until a predetermined criterion is satisfied. Laser output values P2, P4, P6, . . . , at the last moment in each trial of laser oscillation are recorded. Then, each difference between the laser outputs at the last moments of two neighboring or continuous trials, is calculated. When the difference is lower than a predetermined criterion value, the preparation of the laser unit is judged to be completed.

Abstract: The present invention is directed to a method and system for providing phase modulated current to a semiconductor laser to control beam wavelength. A first current is received into a gain portion of the semiconductor laser and a second current is received into a DBR portion of the semiconductor laser. The second current is phase modulated based upon a required intensity value. An output beam is generated by the semiconductor laser based upon the received first current and the received second current.

Abstract: A laser diode is employed to output light. A laser driver is employed to drive the laser diode. A laser driver control unit is employed to control the driving, such that carrier concentration of the laser is substantially forced to a desired concentration as photon level of the laser initially arrives at a desired level. In one embodiment, the laser driver outputs a drive pulse to drive the laser diode, with the drive pulse having a complex waveform. In one embodiment, the complex waveform includes different transition time periods, and transient rates to raise the drive pulse from an initial level to a peak level. In another embodiment, the complex waveform includes different transition time periods and transient rates to raise the drive pulse from an initial level to a transition peak level and then drop the drive pulse back to an intermediate low level and then finally transition to a final peak level.

Abstract: A method embodiment of the invention includes a scheme for trimming and compensation of a laser emitter in a fiber optic link. A laser emitter is provided. Also a reference optical power value is determined using data models of laser emitter performance generated by statistical analysis of sample population of lasers that are similar to the subject laser emitter. The performance of the subject laser is measured and qualified optical power levels for the subject laser emitter are determined using the reference operating power value and measured performance of the subject laser emitter. The driving current of the subject laser emitter is adjusted to compensate for changes in temperature until the optical power of the subject laser emitter obtains a desired qualified optical power level. Related methods of determining qualified optical power levels for a laser emitter in a fiber optic link are also disclosed.

Abstract: A laser head generating ultrashort pulses is integrated with an active beam steering device in the head. Direct linkage with an application system by means of an adequate interface protocol enables the active device to be controlled directly by the application system.

Abstract: VCSEL array with a structure in which vertical cavity surface emitting devices are arranged on a substrate. The VCSEL array includes first and second optical devices. The second optical device receives light that is directed parallel to the substrate and emitted from the first optical device and converts the light into an electric signal when a voltage applied to the second optical device is switched to a reverse bias. The second optical device emits light that is directed parallel to the substrate when a voltage applied to the second optical device is switched to a forward bias.

Abstract: An automatic power control system provides a control signal that regulates the output power of at least one laser diode. Coarse adjustment of the control signal is provided by a first means, preferably a digital variable resistor, while fine adjustment and compensation is provided by a second means, preferably by a digital-to-analog converter that receives an input signal proportional to a sensed control system parameter. The control system includes an operational amplifier having a first input coupled to sense output power, and a second input coupled to a DAC to provide finer resolution control. Memory can store system parameter or system parameter variations that can be coupled to the DAC and/or variable resistor to enhance system stability over ambient variations.