Abstract: A laser transmitter used in an optical communication system provides automatic compensation/stabilization of CNR (carrier to noise ratio) and OMI (optical modulation index) in conditions that would have caused these parameters to change if the compensation circuitry was not employed. The compensation circuitry is an open loop that operates in conjunction with a conventional APC (automatic power control) loop. When certain parameters change (i.e., temperature, laser aging, intentional change in optical power) they will affect the laser DC current (either directly or because of the existence of the APC loop) and as a result the CNR/OMI will change. The compensation circuitry senses the change in the laser DC current and changes the modulating current to the laser as required to minimize changes in CNR/OMI.

Abstract: There is provided a semiconductor laser driving circuit. The circuit has: an amplifier for receiving an emission level setting voltage, and outputting a first driving signal on the basis of the emission level setting voltage; a driving signal generation circuit for receiving a control signal for instructing a light-emission period of a semiconductor laser, and the first driving signal output from said amplifier, and outputting a second driving signal corresponding to a level of the first driving signal in accordance with a light-emission or extinction period; a driving circuit for receiving the second driving signal output from said driving signal generation circuit, and generating and outputting a driving current to be supplied to the semiconductor laser; and a control circuit for receiving the emission level setting voltage, and adjusting a level of the second driving signal during the extinction period in correspondence with the emission level setting voltage.

Abstract: A drive circuit of a light emitting element capable of setting a desired constant current and capable of operating stably at a high speed while holding a forward direction voltage required for the emission of light even under a low power supply voltage, wherein there is provided an input circuit which receives differential drive signals and outputs differential signals of levels in accordance with the level of a supplied drive voltage, a differential output circuit in which an emitter-connection portion of transistors is grounded via a resistor, the differential signals and are supplied to bases, and a laser diode is connected to a collector of the transistor, a reference voltage generation circuit which generates a reference voltage, a comparison circuit which compares the voltage of the emitter-connection portion with the reference voltage and outputs a signal of the level in accordance with the result of comparison, and a variable voltage supply circuit which generates a voltage in accordance with the inpu

Abstract: Disclosed is a two-level current driver suitable for driving a semiconductor laser for printing applications, the laser driver including a primary power source for producing a first current pulse of amplitude I.sub.1 and of duration T.sub.2, a secondary power source for producing a second current pulse of amplitude I.sub.2 and of duration T.sub.1, means for combining the outputs of the power sources, and sensing means for detecting the current pulse output from the primary power source.

Abstract: A fiber laser system including multiple fiber lasers fabricated to emit at respective different wavelengths when optically pumped by radiation at a pump wavelength. A pump laser emits the pump radiation and pumps one or more of the fiber lasers. The outputs of the fiber lasers are recombined onto a transmission fiber, preferably for use in a wavelength-division multiplexing (WDM) telecommunication system. In one set of embodiments, an optical switch switches the pump radiation to only one of the fiber lasers. A second switch controlled in correspondence to the first switch or a passive combiner, preferably a wavelength-division multiplexer, directs the output of the lasing fiber to an optical output path. In another embodiment, the one pump laser simultaneously pumps all the fiber lasers. One or more pump laser may be placed in parallel, and their outputs are combined. The parallel pump lasers may either be individually activated for redundancy or simultaneously operated for higher power.

Abstract: A system for monitoring the amount of light emitted from a surface emitting laser includes a beam splitter which is fixed to the surface emitting laser and splits a part of a laser beam emitted from the laser as a monitor light, and a photodetector which detects the monitor light.

Abstract: A driving method of the present invention drives a semiconductor laser which is provided with at least first and second electrodes through each of which current is injected into the semiconductor laser. Varying current is injected through the first electrode when the frequency of the varying current is in a high frequency band. Varying current is injected through the first electrode while phase-shifted current, whose phase is shifted relative to the varying current, is injected through the second electrode, when the frequency of the varying current is in a low frequency band which is lower than the frequency of the high frequency band. Feedback-control may be performed for controlling a ratio between amplitudes of the modulation current and the phase-shifted current based on a light output from the semiconductor laser.

Abstract: A stabilized laser is comprised of a laser for generating radiation responsive to a control signal. A control circuit connected to the laser provides the control signal and an injection circuit injects a radio frequency into the control circuit and the control signal. A back facet photodiode sensor detects radiation emitted from a back faceted laser diode and provides a feedback signal to the control circuit for adjusting laser output power.

Abstract: A laser diode 11 performs switching operation with a high speed in response to a digital-modulated electric signal inputted in differential input terminals 10a and 10b. At this time, a voltage detecting portion 14 detects a terminal voltage of the laser diode 11. A peak detecting portion 15 detects a peak value of output of the voltage detecting portion 14. A current control portion 16 controls a drive current of the laser diode 11 in accordance with an output of the peak detecting portion 15. The current control portion 16 includes a reference voltage generating portion 16a generating a reference voltage, and an error detecting portion 16b detecting an error between the reference voltage generated by the reference voltage generating portion 16a and the output of the peak detecting portion 15. In accordance with an output signal of the error detecting portion 16b, the drive current of the laser diode 11 is controlled.

Abstract: A method and apparatus for laser frequency stabilization and precise laser frequency tuning comprises splitting a laser beam into two beam portions and recombining the two portions after they traverse differing optical distances. The thus-processed combined beam exhibits a time variation in intensity, the time variation being a function of the time rate of change of the laser beam. A signal proportional to the laser frequency's time rate of change is derived from the time variation of the processed beam's intensity and used to generate a control signal to provide feedback to control the laser frequency, thereby providing for laser frequency stabilization. Precise laser frequency tuning may be achieved by introducing a controlled variation in the derived signal, such as by adjusting a frequency differential introduced between the beam portions, or by otherwise introducing a controlled variation in the signal derived from the processed beam.

Abstract: A laser system which generates short duration pulses, such as under five nanoseconds at an energy level of up to a few milli-Joules per pulse (mJ/p) with near diffraction limited beam quality. A laser crystal is pumped (excited) by diode lasers. A resonator having at least two mirror surfaces defines a beam path passing through the laser crystal. The beam path in the resonator is periodically blocked by a first optical shutter permitting pump energy to build up in the laser crystal, except for a short period near the end of each pumping period. While the first optical shutter is open a second optical shutter blocks the light in the resonator except for periodic short intervals, the intervals being spaced such that at least one light pulse traveling at the speed of light in the resonator is able to make a plurality of transits through the resonator, increasing in intensity by extracting energy from the excited laser crystal on each transit.

Abstract: A circuit for presenting one or more current source outputs which may be used to optimize the interface between optical components in a computer system. The multiple currents may be independently varied in each particular component to provide a current adjustment for proper functioning of a wide variety of LEDs and photo transistors. As a result, a dynamic optimization of the devices is provided. Since the present invention allows a wide variety of optical components to be used, the overall cost of implementing the device may be reduced.

Abstract: The invention features an apparatus providing electromagnetic radiation including: a first non-linear optical crystal for converting input radiation from a laser into intermediate radiation; a second non-linear optical crystal for converting the intermediate radiation into output radiation; and a plurality of optics forming an optical cavity that encloses the first and second non-linear optical crystals, substantially confines and resonates the intermediate radiation, and has a cavity length matching the cavity length of the laser to within less than the coherence length of the input radiation. The apparatus can be used to convert the output from a multimode, diode-pumped, solid-state laser into high power ultraviolet radiation.

Abstract: A laser apparatus employing a semiconductor laser or the like, and a method of controlling the laser apparatus capable of controlling an driving a temperature control unit on the basis of the sum of the respective power consumptions of the temperature control unit and a driving means so that the laser apparatus operates at a minimum power consumption. The temperature control unit included in a laser oscillator heats or cools a nonlinear optical medium, a temperature detecting means detects the temperature of the nonlinear optical medium, a power consumption detecting unit detects the respective power consumptions of the temperature control unit and the driving means, and a processing means controls and drives the temperature control unit on the basis of the sum of the respective power consumptions of the temperature control unit and the driving means.

Abstract: A method of and apparatus for measuring chirp passes an input modulated optical signal through a Waveguide Grating Router (WGR) and processes the signals from adjacent WGR output ports in an oscilloscope, to obtain the real-time dynamic chirp measurements of the modulated optical signal.

Abstract: A laser apparatus capable of emitting a laser beam upon wavelength conversion and intensity modulation, which comprises a fundamental wave resonance means comprising a light emitting part, an optical resonator comprising mirrors sandwiching the light emitting part and capable of laser resonating, and a modulation-conversion means set inside said optical resonator, said light emitting part being a semiconductor light emitting element or a laser medium, said modulation-conversion means converting, by a nonlinear optical effect, a fundamental laser resonance wavelength light, and phase modulating said light by an electro-optical effect, and a modulation part of said modulation-conversion means comprising electrodes for application of a modulation voltage.

Abstract: In a laser beam processing apparatus, a laser monitor comprises a photo sensor, a laser power measuring circuit, an A-D converter, a monitor control unit, a comparison decision unit, a display control unit, a display, an alarm generating circuit and a buzzer. A measured laser power signal (analog voltage signal) representative of an instantaneous value of laser power of a pulsed laser beam is produced by the photo sensor and the laser power measuring circuit, and the digital measured laser power signal from the A-D converter is supplied to the comparison decision unit and to the monitor control unit. The monitor control unit sets or determines a monitor reference waveform corresponding to a laser control reference waveform used for waveform control in the processing apparatus and controls the comparison decision unit. The comparison decision unit provides a monitoring decision on the power of the pulsed laser beam, which is displayed by a visual presentation or by display lamps on the display.

Abstract: A laser diode power controller, and method, are disclosed. The controller can be implemented entirely in CMOS technology due to the simplicity of its quasi-decision-based control routines. The control routines involve the use of a window comparator which determines whether the measured power level of a laser diode falls within a desired range of values. The simplified control routines are also manifested by the use of digital registers to set the desired current values that are to be output to the laser diode and monitor diode. The modulation current supplied to the laser diode exhibits much lower noise levels because the modulation digital to analog converter (DAC) By supplying a continuous current that is selectively switched between the laser diode and a dummy load, much less noise is induced in the power supply than if it had to respond to large changes in modulation current, i.e., OFF (zero) and ON (desired Imod).

Abstract: In the apparatus for driving a laser diode, a light receiving element detects a light output level of the laser diode to produce an electric signal. That is, the light receiving element detects a first electric signal when the laser diode is driven based upon an ON signal, and a second electric signal when the laser diode is driven based upon an OFF signal. A control circuit outputs a control signal in response to the signal. A driving circuit drives the laser diode in response to the control signal such that a difference between the first electric signal and the second electric signal is maintained at a constant value.

Abstract: A temperature compensated laser diode transmitter circuit includes a laser diode, a driver circuit for supplying an a.c. drive current to the laser diode, a thermistor arranged to thermally sense the laser diode, a current source having a first and a second current output controlled by the thermistor, the first current output connected to the driver for temperature compensating the drive current, and the second current output connected to supply a temperature compensated bias current to the laser diode.

Abstract: A laser light quantity control device includes a semiconductor laser element having a plurality of light emitting portions and a light quantity detector for detecting light quantities of the individual light emitting portions. Currents supplied to the individual light emitting portions are controlled by a light quantity adjusting section on the basis of outputs from the light quantity detector. The light quantity adjusting section performs light quantity adjustments of the individual light emitting portions at predetermined time interval.

Abstract: The present invention relates to a semiconductor laser drive device, and an image recording device whose function includes scanning a predetermined body to be scanned with a laser beam carrying image information in the course of recording an image, and which makes high speed image regeneration while maintaining a high quality of the image, wherein the devices are equipped with a first feedback circuit including a first operational amplifier and a second feedback circuit including a second operational amplifier, so that the double feedback can concurrently be effected to obtain current vs. light output characteristics with a high speed and high accuracy in an analog mode.

Abstract: A circuit and method for driving a laser diode with high stability. A steady state current is generated and used to drive the laser diode. A dynamic feedback signal is generated and used to operate the laser diode in a constant power mode. An operational amplifier having a transistor and an RC circuit in the feedback loop is used to couple the drive voltage source to the laser diode. A potentiometer in the inverting amplifier input is used to control the laser diode output current amplitude. A longevity signal is provided to indicate whether or not the laser diode current is excessive.

Abstract: The present invention relates to a laser beam emitting apparatus employing a semiconductor laser or the like and, more particularly, to a laser beam emitting apparatus capable of operating at low power consumption. A Peltier device driving unit of the present invention drives a Peltier device included in the laser beam emitting apparatus provided with an optical resonator having at least a laser crystal and an output mirror. A switching regulator generates a voltage corresponding to the duty factor of a pulse width modulator. An H-bridge changes the flowing direction of a current supplied to the Peltier device. The H-bridge comprises p-channel FETs, and n-channel FETS connected in parallel with the p-channel FETS.

Abstract: Superresolution elements which provide masks and are integrated into superresolution lenses, and in confocal imaging, optical disk and reprographic systems and laser pattern generation systems. The elements are phase-only elements, where the phase transmittance varies across the diameter of the element while the amplitude transmission is kept to one, although the amplitude can be varied to provide more design flexibility. These element filters can be fabricated by means of a variety of techniques including diffractive optics technology, holographic methods, thin film deposition, and as gradient-index elements.

Abstract: A laser cavity assembly includes means (12, 13, 14; 14", 56, 57) defining respective optical resonance cavities (20, 22) for stimulated radiation of different wavelengths, which cavities include at least some common volume. Such means includes window means (13, 14) for emission of radiation amplified in the respective cavities. Means (15, 54) in one of said cavities is responsive to stimulated radiation emitted by a laser medium at one of the wavelengths to emit radiation at another of the wavelengths. Dual mode means (12, 54) has respective selectable first and second modes at which the laser cavity assembly is adapted to emit laser radiation predominantly at the respective wavelengths. Also disclosed are a novel Q-switch device and a combination laser oscillator and dual mode means.

Abstract: A light intensity controlling device has a beam splitter which splits light fluxes emitted from a plurality of independently controlled semiconductor lasers, guided by optical fibers, into monitor light fluxes and main light fluxes. A gain adjusting circuit corrects the changes of output of light receiving elements depending on the polarization states of the light fluxes incident into the beam splitter. The changes result from the polarization characteristics of the optical fibers and/or the beam splitter. Alternatively, a filter is provided at one of the light receiving elements to compensate for the changes, thus providing a corrected output signal. Laser control circuits control the light emitting intensity of each semiconductor laser based on corrected output signals. The light receiving elements are set at an angle to the incoming light as so to avoid directing reflected light back toward an imaging system or the lasers.

Abstract: A bias controller for a semiconductor laser, for example, a laser having an light output which exhibits a threshold at a threshold value of an input drive current, is disclosed. The bias controller includes a test signal generator arranged to generate a low frequency test signal which is the superposition of a modulated control signal on a DC bias signal which is applied to the laser as a drive current superimposed on a high frequency data signal. A detector is arranged to determine the value of either the third harmonic component, or the second harmonic component, of the light output of the laser. A control means is arranged to control the DC bias current to have a value close to the threshold value by maintaining the detected value of the harmonic component of the light output of the laser near to a predetermined value.

Abstract: An electro-optical apparatus transforms a single frequency, linearly polarized laser input beam (18) from a light source (10) into an output beam (36) having two collinear orthogonally polarized output beam components (32,33) differing in frequency from each other by the frequency of a stabilized electrical signal (40) provided from an electronic oscillator (38). The output of the oscillator (38) is provided to a power amplifier (42) which is used to drive a piezoelectric transducer (46) affixed to an acousto-optical Bragg cell (52) through which the input beam (18) passes and is transformed into the output beam (36) composed of two beam components (32,33). The electrical output (44) of the power amplifier (42) is adjusted so that each of the output beam components (32,33) has approximately a preselected fraction of the intensity of the input beam (18).

Abstract: An optical recording/reproducing apparatus has a laser diode and a semiconductor integrated circuit device for driving the laser diode. The semiconductor integrated circuit device has a driver circuit for producing a drive current to be supplied to a laser diode in accordance with an input signal representative of a laser beam power varying depending on a relative speed between a magneto-optical disk and a spot of a laser beam emitted by the laser diode on the optical disk. The driver circuit has a non-linear first operation range and a substantially linear second operation range subsequent to the first operation range. For a linear operation of the driver circuit, a level shifter circuit is connected to the driver circuit for applying a shift voltage to the driver circuit with a result that an excess output current is produced by the driver circuit even when the input signal is non-existent.

Abstract: The illumination energy of an excimer laser is measured and adjusted to always effect illumination at constant energy. A laser beam output from an optics is reflected by a mirror, and applied to a sample. A beam profiler is disposed behind the mirror to measure the energy of an illumination laser beam. An energy attenuating device disposed between another mirror and the optics is operated based on the measurement value so that the energy of the laser beam applied to the sample is kept constant.

Abstract: A semiconductor laser package including a mounting structure at least partially encapsulating a vertical cavity surface emitting laser and a photodetector. The vertical cavity surface emitting laser generating an emission along a path. The photodetector optically positioned and/or integrally formed with the vertical cavity surface emitting laser to receive a portion of the emission. An optical element is optionally positioned in the path, mounted on the mounting structure utilizing a snap-fit connection, a threaded or adhesive mounting. The mounting structure and optical element are fabricated to allow for proper z-axis alignment of the optical element relative to the laser emission aperture.

Abstract: A laser system capable of providing light of high intensity is disclosed. This system includes a laser gain medium and three reflectors. A first reflector and a second reflector spaced from the first reflector define a laser cavity that contains the laser gain medium. Light reflected by the first reflector is amplified by the laser gain medium. A third reflector is spaced from the second reflector to define a resonant cavity external to the laser cavity. Light passes from the laser cavity to resonate in the external resonant cavity. Part of the light passes from the external resonant cavity to the laser cavity. A light-screening device, e.g., an aperture, is disposed between the second reflector and the gain medium to screen light reflected from the external cavity such that the light portion of constructive interference is preferentially passed over the light portion of destructive interference. This enables the gain medium to optically lock to the resonant frequency of the external cavity.

Abstract: An X-ray laser generating apparatus comprises a laser oscillator for generating a pulse laser beam, a pulse train converter for converting the pulse laser beam into a pulse train laser beam, an optical device for focusing the pulse train laser beam to a thin line, a target material placed at the laser beam focused position and generating high temperature plasma containing highly charged ions with irradiation of the linearly focused pulse train laser beam, a vacuum chamber for keeping a vicinity of the irradiated region of the target material under a decompressed state, and a pair of X-ray reflecting mirrors positioned on both sides of the target material and on the extended thin line, and at least one of the paired mirrors partially transmits X-ray.

Abstract: A laser scanning unit emits a laser beam for scanning a surface within a predetermined scanning range. The laser scanning unit has a laser diode, and a laser diode controller for controlling the laser diode to emit the laser beam. The laser beam has an intensity set in accordance with image data corresponding to one of a plurality of predetermined graduation steps within an intensity range defined by a first intensity and a second intensity greater than the first intensity. The laser scanning unit is further provided with a first adjusting system for adjusting the first intensity to become a first predetermined intensity, and a second adjusting system for adjusting the second intensity to become a second predetermined intensity. One of the first adjusting system and the second adjusting system is actuated during each scanning operation, and are actuated alternately during successive scanning operations.

Abstract: An optical communications source has a laser optically coupled with an external optical modulator (25). The laser has a long optical cavity and a narrow spectral bandwidth Bragg reflector (24) so that the longitudinal mode separation of the laser emission is small compared with the spectral bandwidth of the reflector. This makes the laser operate multi-mode, but without any significant dispersion penalty.

Abstract: The present invention is concerned with a gas laser oscillator apparatus based on gas discharge excitation having a power supply unit, rectifying means connected to the power supply unit, a smoothing capacitor connected in parallel with the rectifying means, a choke coil connected in series with the rectifying means and a laser tube connected in parallel with the smoothing capacitor and in series with the choke coil, wherein a smoothing capacitor capacitance C and an inductance L of the choke coil are determined byf>1/2.pi..sqroot.LC.Even when with this construction, the capacitance C of the smoothing capacitor is set tof>1/2.pi..sqroot.LC,a ripple of a current flowing to the laser tube can be smaller than that in the conventional apparatus and a stable laser output can be obtained.

Abstract: In order to set the output optical power of a laser diode precisely and under digital control without expensive digital to analog conversion devices, a digital controller provides a sequence of pulses. A capacitor is charged by these pulses to produce a control voltage which controls the current through the laser diode via an operational amplifier driver stage. The output power obtained from the laser as detected by a photodetector, which is optically coupled to the laser and may be packaged therewith, is monitored by the computer so as to determine the rate at which laser power changes and indirectly at the rate at which the capacitor charges. This rate may vary depending upon environmental conditions and manufacturing tolerances. Based upon the charging rate, a pulse is generated and used to either provide additional charge or to charge the capacitor to the voltage corresponding to the desired optical power output.

Abstract: A method of producing a high power and brightness beam from diode laser source that either has a single emitting element or array with a plurality of segments or emitters that are concurrently addressable, or has a plurality of elements or subarrays each having a plurality of laser segments or emitters, which elements or subarrays are independently addressable relative to one another. Beam filling and focusing optics are disposed in front of the emitters so that light from the individual emitters from each subarray converge to from a single overlapping spot. Segmentation of laser subarrays and emitters improves laser life by reducing thermal gradients and isolating any local failures to a single segment emitters, while the focusing of the segments or emitters to overlapping light spots increases the tolerance of the source to local failures. Two or more emitters in a given element must fail before the source is considered to have failed.

Abstract: A high average power, high brightness solid state laser system. We first produce a seed laser beam with a short pulse duration. A laser amplifier amplifies the seed beam to produce an amplified pulse laser beam which is tightly focused to produce pulses with brightness levels in excess of 10.sup.11 Watts/cm.sup.2. Preferred embodiments produce an amplified pulse laser beam having an average power in the range of 1 kW, an average pulse frequency of 12,000 pulses per second with pulses having brightness levels in excess of 10.sup.14 Watts/cm.sup.2 at a 20 .mu.m diameter spot which may be steered rapidly to simulate a larger spot size. Alternately, a kHz system with several (for example, seven) beams (from amplifiers arranged in parallel) can each be focused to 20 .mu.m and clustered to create effective spot sizes of 100 to 200 .mu.m. These beams are useful in producing X-ray sources for lithography.

Abstract: In order to set the output optical power of a laser diode precisely and under digital control without expensive digital to analog conversion devices, a digital controller provides a sequence of pulses. A capacitor is charged by these pulses to produce a control voltage which controls the current through the laser diode via an operational amplifier driver stage. The output power obtained from the laser as detected by a photodetector, which is optically coupled to the laser and may be packaged therewith, is monitored by the computer so as to determine the rate at which laser power changes and indirectly at the rate at which the capacitor charges. This rate may vary depending upon environmental conditions and manufacturing tolerances. Based upon the charging rate, a pulse is generated and used to either provide additional charge or to charge the capacitor to the voltage corresponding to the desired optical power output.

Abstract: The present invention relates to a semiconductor laser control method used preferably for a reading control system such as a bar code reading device and to a semiconductor laser control device employing the above method. The object of the invention is to provide a semiconductor laser control device which can be controlled based on the output of a semiconductor laser, provides a stable laser output in a noise environment, enables easy output adjustment, and is immune to external thermal or electrical noises. In the semiconductor laser control method where the light amount of a light amount to current controllable semiconductor laser is subjected to a feedback control with a predetermined time constant while it is monitored, when the light amount is less than a predetermined value, the semiconductor laser is subjected to an feedback control with a first time constant. When the light amount is more than a predetermined value, the semiconductor laser is subjected to a feedback control with a second time constant.

Abstract: A power monitoring system including a vertical cavity surface emitting laser generating an emission. A beam splitter optically positioned to receive the emission and split the emission into a first portion and a second portion. A monitor optically positioned to receive the first portion of the emission. An output of the monitor is used to control emissions of the vertical cavity surface emitting lasers.

Abstract: A laser light generator includes an adder 12 which adds an optical frequency modulation signal Sm onto a d.c. voltage for driving a laser diode 10 for continuous laser oscillation, and applies the sum signal to the laser diode 10 to drive it. An light output from the laser diode 10 is introduced to an optical intensity controller 14 that is controlled by a control signal prepared by adjusting the optical frequency modulation signal Sm both in phase and in amplitude by a phase adjusting circuit 16 and an amplitude adjusting circuit 18. The optical intensity controller 14 may be an electroabsorption modulator that changes its transmissivity in response to an output voltage of the circuit 18. Quantities of adjustment by the circuits 16 and 18 are determined so that fluctuation in transmissivity of the optical intensity controller 14 suppresses intensity fluctuation of the light output of the laser diode 10.

Abstract: An integrated laser-based light source that generates an output light beam having a controlled intensity. The light source comprises a package in which are mounted a laser, a light sensor and a coupler. The laser has one and only one light-emitting face from which a light beam is radiated as a radiated light beam. The light sensor generates an electrical signal representing the intensity of light energy falling it. The coupler couples a fraction of the radiated light beam to the light sensor, and provides the remainder of the radiated light beam as the output light beam. Since the light coupled to the light sensor by the coupler is a fraction of the radiated light beam, the electrical signal generated by the light sensor also represents the intensities of the radiated light beam and of the output light beam.

Abstract: An integrated laser-based light source that generates an output light beam having a controlled intensity. The light source comprises a package in which are mounted a laser, a light sensor and a coupler. The laser has one and only one light-emitting face from which a light beam is radiated as a radiated light beam. The light sensor generates an electrical signal representing the intensity of light energy falling it. The coupler couples a fraction of the radiated light beam to the light sensor, and provides the remainder of the radiated light beam as the output light beam. Since the light coupled to the light sensor by the coupler is a fraction of the radiated light beam, the electrical signal generated by the light sensor also represents the intensities of the radiated light beam and of the output light beam.

Abstract: A process and circuit arrangement for regulating the luminous power of a laser diode in an optoelectronic point-by-point or line recording device for recording information on a recording material. A deviation is determined by comparing a luminous power set value to a measured luminous power real value. A fast regulator generates a regulating current based on the deviation. A slow regulator with storage capabilities generates a working point regulating current that determines the working point on a laser diode characteristic curve and that is added to the regulating current to provide the driving current of the laser diode. The luminous power set value and the slow regulator are used during the switching-on periods of the laser diodes at the beginning of the recording periods and during preliminary periods that precede the recording periods.

Abstract: A power monitoring system including a first substrate having a first vertical cavity surface emitting laser and a second vertical cavity surface emitting laser formed thereon and being generally identical. A second substrate having a photodiode formed thereon. The second substrate is flip chip mounted on the first substrate with the photodiode in optical alignment the second vertical cavity surface emitting laser. The output of the photodiode is used to control emissions of the first and second vertical cavity surface emitting lasers.

Abstract: To obtain a predetermined power intensity without influencing the wavelength of output light by external APC, a laser beam having a predetermined plane of polarization and output from a tunable wavelength light source passes through a Faraday element and a polarizer constituting an optical attenuator and is split into a split light beam and an output light beam by a beam splitter. The split light beam is received by a light-receiving device, and a detection signal according to the power intensity is output from the light-receiving device. A controller supplies a signal according to the difference between the detection signal output from the light-receiving device and a set value set at an intensity setting device to a coil of the Faraday element constituting the optical attenuator.

Abstract: A power stabilizer for maintaining a constant level of output power from a laser transmitter. The laser transmitter has a laser diode which produces an optical output which corresponds to the level of bias current received. In addition, the laser transmitter has a photodiode which produces a feedback signal which corresponds to the optical output power being produced by the laser diode. Furthermore, the power stabilizer consists of a digitally controlled potentiometer for producing a reference input signal and an op-amp for comparing the feedback signal and the reference input signal to produce a control signal to supply bias current.