Abstract: A laser assembly for use with an additive manufacturing system, which includes a base block configured to be moved along a scan direction axis in the additive manufacturing system, a plurality of laser emitters preferably arranged in an array of at least two rows of two or more laser emitters. At least a portion of a heat sink assembly is configured to draw heat away from the base block and/or the laser emitters. The assembly includes a controller assembly a controller assembly configured to control a movement of the base block along the first axis and to independently control at least timing and duration of energy emitted from each laser emitter of the plurality of laser emitters as the base block moves along the first axis.

Abstract: An optical arithmetic-logical unit [“ALU”] processes one or more combined input signals, which result from a combination of multiple elementary input signals, each of which comprises at least one polarization component. One of the combined input signals is a synchronization signal having a phase and an amplitude. At least one laser has an output and is configured to synchronize with the synchronization signal, wherein the synchronization of the laser with the synchronization input signal generates an output signal, which preserves the phase of the synchronization signal but normalizes its amplitude. Generation of the output signal by said normalization of the synchronization signal provides the ALU with a capability of performing one or more arithmetic-logical operations on the one or more combined input signals.

Abstract: Aspects are generally directed to optical signal receivers and methods. In one example, a receiver includes an optical resonator assembly configured to receive an optical signal at each of a plurality of optical resonators, each optical resonator configured to resonate optical signal energy at a corresponding frequency of the received optical signal, each optical resonator being tuned to a different corresponding frequency of the received optical signal, and each optical resonator being configured to output corresponding output optical signal energy. The receiver includes a detector assembly to detect the corresponding output optical signal energy from each optical resonator, and a signal processing circuit configured detect a frequency variation of the received optical signal based on the corresponding output optical signal energy from at least two of the plurality of optical resonators, and configured to generate a digital signal based on the frequency variation.

Abstract: Provided is a passively Q-switched element or the like, which enables mode selection without increasing the number of components in a resonator in a Q-switched pulse laser or the like that oscillates in a great number of high-order modes and which is also applicable to a waveguide type laser in which a mode cannot be controlled spatially. By combining a saturable absorber (2) with a transparent material (3) which is transparent to a laser oscillation wavelength or the like, a passively Q-switched element having a mode selection function and a passively Q-switched laser device in which a passively Q-switched element has a mode selection function, and a planar waveguide type passively Q-switched element and passively Q-switched laser device are provided.

Abstract: Embodiments of the invention describe integrating a phase shifting component into a cavity of a laser. Said phase shifter is capable of a continuous phase shift at a single wavelength over a large range (where the maximum energy consumption of the phase shifting component does not scale with the phase shifting range). In other words, said phase shifter is used to form a configurable optical cavity length for a laser. Embodiments of the invention thus utilize a plurality of optical cavity lengths—including one or more optical cavity lengths to potentially shift the phase of the output optical signal, to maintain a laser cavity's output wavelength and avoid spatial mode-hops in the presence of fluctuations such as temperature drift or changes to the drive current of the laser.

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

Abstract: An opto-electronic oscillator circuit, including: an opto-electronic circuit loop including an optical modulator that receives a first electrical signal and produces an optical output signal coupled with an optical resonator, a photodetector circuit optically coupled with the optical resonator, and a phase shifter coupled with the photodetector circuit for producing a phase shifted output signal that is fed back as the first electrical signal; an optical loop comprising the optical coupling of the optical resonator with the photodetector; and an electrical feedback circuit loop for coupling the first electrical signal with the photodetector circuit.

Abstract: Embodiments of the invention describe an illuminator having a light source to originate an illumination beam, wherein the light source further comprises a set of vertical-cavity surface emitting lasers (VCSELs), including a first VCSEL having a first laser emission wavelength, and a second VCSEL having a second laser emission wavelength different than the first laser emission wavelength. Thus, by varying laser emission wavelengths of VCSELs in a VCSEL array, embodiments of the invention produce low-contrast speckle, and do not limit the imaging capabilities of the host illumination system. In some embodiments of the invention, vertical external cavity surface emitting lasers (VECSELs) are utilized to produce the above described varying laser emission wavelengths.

Abstract: A master oscillator may include: a pumping laser that outputs pumping light; a seed laser that is oscillated by the pumping light; an amplifier that amplifies the pulsed laser light outputted by the seed laser using the pumping light; at least one optical shutter disposed in the optical path between the seed laser and the amplifier; and a controller that causes the pumping laser to oscillate continuously at a predetermined repetition rate and that controls the optical shutter to open and close.

Abstract: A laser system may include a master oscillator that outputs pulsed laser light, an amplification device that amplifies the pulsed laser light outputted from the master oscillator, and a controller that controls the master oscillator and the amplification device. The master oscillator may have a pumping laser that outputs pumping light, a seed laser that is oscillated by the pumping light, an amplifier that amplifies the pulsed laser light outputted by the seed laser using the pumping light, and at least one optical shutter disposed in the optical path between the seed laser and the amplifier. The controller may control the opening and closing of the optical shutter and discharging of the amplification device so that the amplification device discharges when the pulsed laser light that has passed through the optical shutter passes through the amplification device.

Abstract: A gain medium and an interband cascade laser, having the gain medium are presented. The gain medium can have one or both of the following features: (1) the thicknesses of the one or more hole quantum wells in the hole injector region are reduced commensurate with the thickness of the active hole quantum well in the active quantum well region, so as to place the valence band maximum in the hole injector region at least about 100 meV lower than the valence band maximum in the active hole quantum well; and (2) the thickness of the last well of the electron injector region is between 85 and 110% of the thickness of the first active electron quantum well in the active gain region of the next stage of the medium. A laser incorporating a gain medium in accordance with the present invention can emit in the mid-IR range from about 2.5 to 8 ?m at high temperatures with room-temperature continuous wave operation to wavelengths of at least 4.

Abstract: A light pointer apparatus and method of use comprising: a substantially flat bottom surface comprising a sufficiently large surface area such that when said substantially flat bottom surface is rested upon a substantially flat horizontal surface, said apparatus remains substantially immobile and stable relative to the substantially flat horizontal surface solely by virtue of the plane of contact formed between said substantially flat bottom surface and the substantially flat horizontal surface; a light source for emitting a low-divergence light beam comprising wavelengths in the visible light spectrum with a beam divergence of at most three degrees, fixed in orientation relative to said substantially flat bottom surface so as to emit said low-divergence light beam at a predetermined emission angle of at least 45 degrees relative to said substantially flat bottom surface; and surfaces other than said substantially flat bottom surface capable of being held and moved by a human hand.

Abstract: A wavelength-tunable directly modulated fiber ring laser is provided. Generally speaking, the wavelength-tunable directly modulated fiber ring laser employs an RSOA (reflective semiconductor optical amplifier) and an OTF (optical tunable filter) to construct a novel ring resonant cavity. Additionally, a signal generator can be further employed to transmit modulated signals to the RSOA, whereby generating light wave with the modulated signals, so as to provide tunable wave-length and direct modulation at the same time.

Abstract: A gain medium and an interband cascade laser, having the gain medium are presented. The gain medium can have one or both of the following features: (1) the thicknesses of the one or more hole quantum wells in the hole injector region are reduced commensurate with the thickness of the active hole quantum well in the active quantum well region, so as to place the valence band maximum in the hole injector region at least about 100 meV lower than the valence band maximum in the active hole quantum well; and (2) the thickness of the last well of the electron injector region is between 85 and 110% of the thickness of the first active electron quantum well in the active gain region of the next stage of the medium. A laser incorporating a gain medium in accordance with the present invention can emit in the mid-IR range from about 2.5 to 8 ?m at high temperatures with room-temperature continuous wave operation to wavelengths of at least 4.

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

Abstract: A high average power laser system with modulated gain suppression includes an input aperture associated with a first laser beam extraction path and an output aperture associated with the first laser beam extraction path. The system also includes a pinhole creation laser having an optical output directed along a pinhole creation path and an absorbing material positioned along both the first laser beam extraction path and the pinhole creation path. The system further includes a mechanism operable to translate the absorbing material in a direction crossing the first laser beam extraction laser path and a controller operable to modulate the second laser beam.

Abstract: Disclosed is a high current radiation system. The system includes a high current radiation source to generate radiation and an analog circuit to generate, based, at least in part, on an input signal representative of the present current level delivered to the high current radiation source and a user-controlled input representative of a desired current level, an output signal to control a current level to be delivered to the high current radiation source. The system further includes a current driver to control the current delivered to the high current radiation source based, at least in part, on the output signal of the analog circuit.

Abstract: A method is provided to calibrate a monitor photodiode that measures the optical output power generated by an optoelectronic transceiver module that includes a burst mode laser diode. The method includes disabling the power control loop that controls an average optical output power generated by the laser diode during a laser burst. A series of logic zero signals is applied to a data input of the transceiver module and the logic zero level of the optical signal generated by the burst mode laser diode while applying the series of logic zero signals is measured. The logic zero bias level applied to the laser diode is adjusted until the measured logic zero level of the optical signal reaches a first desired value. While maintaining the optical signal at the first desired value, a first value of a current generated by the monitor photodiode in response to optical energy received from a back facet of the laser diode is stored.

Abstract: A display device (100) of the present invention has a first switch (3) and a second switch (4) on an upper surface of its casing, and includes a control circuit (18) for controlling the first switch (3) and the second switch (4) and a light source (19) inside the casing. The control circuit (18) performs control so that the light source (19) is turned on when the second switch (4) is pressed after a predetermined period of time has passed from when the first switch (3) was pressed. Thereby, the display device (100) of the present invention prevents entering of a person into a projection area before projection of video, and controls inadvertent start-up.

Abstract: A laser system (10) is disclosed comprising a laser device (1) for emitting laser radiation and an optical fibre (2) adapted to connect, in use, to the laser device (1) for delivering the laser radiation. The optical fibre contains a label (3), such as an RF identification tag, a barcode or a colour code. The laser device (1) interrogates the optical fibre (2) and receives information back from the optical fibre (2). If the usage of the optical fibre (2) has exceeded safety limits then the laser device (1) may be prevented from operating. The laser device (1) on receiving information from the optical fibre (2) may also be configured to deliver laser radiation having a specific power, pulse width, pulse interval and treatment duration.

Abstract: Apparatus and methods of performing fast single-qubit quantum gates using ultrafast femtosecond frequency chirped laser pulses are disclosed. The use of chirped pulses removes the demanding restrictions of prior art approaches and allows for the construction of fast quantum gates that operate at speeds on the of order several picoseconds. The apparatus includes two synchronized lasers (pump and Stokes) used to manipulate a qubit wave function in a select manner. Each laser system generates a train of optical pulses. Pulse pickers choose pump and Stokes pulses, which propagate though respective pulse shapers that apply necessary time-dependent phases. To achieve complete overlap between the pulses in time domain, necessary adjustments can be made by using an additional time delay line, which can be located in any path or in both paths.

Abstract: Emissive quantum photonic imagers comprised of a spatial array of digitally addressable multicolor pixels. Each pixel is a vertical stack of multiple semiconductor laser diodes, each of which can generate laser light of a different color. Within each multicolor pixel, the light generated from the stack of diodes is emitted perpendicular to the plane of the imager device via a plurality of vertical waveguides that are coupled to the optical confinement regions of each of the multiple laser diodes comprising the imager device. Each of the laser diodes comprising a single pixel is individually addressable, enabling each pixel to simultaneously emit any combination of the colors associated with the laser diodes at any required on/off duty cycle for each color. Each individual multicolor pixel can simultaneously emit the required colors and brightness values by controlling the on/off duty cycles of their respective laser diodes.

Abstract: An optical fiber for performing pulse stretching, and fiber laser systems and methods using the pulse-stretching fiber are disclosed. The pulse-stretching (PS) fiber has low fourth-order dispersion (dispersion curvature) and a third order dispersion (dispersion slope) with a small negative, nearly zero or small positive value. Two different types of fiber laser systems that use the PS fiber in a manner that achieves optimum performance are described. The PS fiber enables an all-fiber (up to the final pulse compressor) ultra-short pulsed laser systems reaching pulse energies exceeding 100 ?J, average powers exceeding 100 W, and output pulse widths of less than 100 fs.

Abstract: A programmable laser pulse combines electrical modulation of the pulse frequency and optical modulation of the pulse shape to form laser pulses of prescribed pulse shapes. A prescribed pulse shape features high peak power and low average power. The laser system disclosed also allows for power-scaling and nonlinear conversions to other (shorter or longer) wavelengths. The system provides an economical reliable alternative to using a laser source with high repetition rates to achieve shaped pulses at a variety of wavelengths. The combinatorial scheme disclosed is inherently more efficient than existing subtractive methods.

Abstract: The laser drive circuit of the present invention includes a first drive circuit 105 receiving an input of a current from a variable current source 103 and a first pulse control signal 101 and outputting a first drive current in synchronism with the first pulse control signal 101; a pulse output circuit 107 outputting a pulse signal in response to a falling edge of the first pulse control signal 101; and a second drive circuit 106 receiving an input of a current from a variable current source 104 and a second pulse control signal 102, generating a second drive current in synchronism with the second pulse control signal 102, and outputting a decreased current value of the second drive current at least in synchronism with the pulse signal. According to this configuration, the falling time of the pulse can be shortened regardless of the relationship between the voltage of a laser connecting terminal and the power source voltage of a drive circuit or a ground voltage.

Abstract: A laser system for a spectroscopic catheter system uses multiple semiconductor gain media having gain peaks at different wavelengths. The output from the gain media is preferably coupled into single-mode fiber using conventional opto-electronic packaging techniques. As a result, the laser oscillator source has a spectral output that is wider than the gain bandwidth of a single medium to enable it to access the entire spectrum of interest, which is presently in the near infrared. Moreover, the semiconductor gain media can be packaged in a stable and controlled environment for long-term performance.

Abstract: A laser system is disclosed comprising a laser device for emitting laser radiation and an optical fiber adapted to connect, in use, to the laser device for delivering the laser radiation. The optical fiber contains a label, such as an RF identification tag, a barcode or a color code. The laser device interrogates the optical fiber and receives information back from the optical fiber. If the usage of the optical fiber has exceeded safety limits then the laser device may be prevented from operating. The laser device on receiving information from the optical fiber may also be configured to deliver laser radiation having a specific power, pulse width, pulse interval and treatment duration.

Abstract: An optical switch, wherein the first and second output ports (optical fibers) are disposed on the opposite sides of the input port (optical fiber) so as to form acute angles with respect to the input port, the input port and the first output port are optically coupled to each other through a first mirror surface, and the input port and the second output port are optically coupled to each other through a second mirror surface. The incident angles of an incident light beam with respect to the mirror surfaces are equalized, and optical path lengths between the input port and the first and second output ports are equalized. The actuator inserts and withdraws the second mirror surface on a position at the front of the first mirror surface.

Abstract: Apparatus and methods of performing fast single-qubit quantum gates using ultrafast femtosecond frequency chirped laser pulses are disclosed. The use of chirped pulses removes the demanding restrictions of prior art approaches and allows for the construction of fast quantum gates that operate at speeds on the of order several picoseconds. The apparatus includes two synchronized lasers (pump and Stokes) used to manipulate a qubit wave function in a select manner. Each laser system generates a train of optical pulses. Pulse pickers choose pump and Stokes pulses, which propagate though respective pulse shapers that apply necessary time-dependent phases. To achieve complete overlap between the pulses in time domain, necessary adjustments can be made by using an additional time delay line, which can be located in any path or in both paths.

Abstract: Methods and system are provided for automatic power control of a laser diode, e.g., in a laser driver. In accordance with an embodiment of the present invention, a power controller includes a detector circuit adapted to detect the output of the laser diode and to produce a measured output therefrom. A comparator compares a desired output to the measured output, and produces an error signal therefrom. The error signal is provided to an integrator circuit that produces an integrated error signal. At least one digital-to-analog converter (DAC) uses the integrated error signal to produce a current drive signal that drives the laser diode.

Abstract: The present invention relates to a fluorine gas discharge laser system and control of replenishment of fluorine gas as the gas discharge laser operates and consumes fluorine.

Abstract: A circuit for disabling an energy-generating component. The circuit comprises an input operable to receive a disable signal and a disable circuit operable to disable the component in response to the disable signal for a predetermined duration of time sufficient to maintain an average power generated by the component at or below a predetermined level. The disable circuit further comprises a signal-detection circuit operable to detect the presence of disable signals having a respective rising edge and falling edge, a mask-signal generating circuit coupled to the signal detection circuit and operable to generate a mask signal when one of the edges of a first disable signal is detected; and a latching circuit coupled to the mask-signal generating circuit and operable to generate a mask disable signal if the mask signal is being generated and the other edge of a subsequent disable signal is detected.

Abstract: A system that transmits amplitude modulated data in a wavelength-encoded format and then uses a wavelength-sensitive receiver to convert the received optical signal back to the original amplitude modulated data. This system enables transmission of optical signals that are less sensitive to attenuation and attenuation changes. This system is applicable to data in digital, multilevel, or analog formats.

Abstract: A light emitting element driving circuit for supplying driving current I2 to a light emitting element 10 connected to one line 2 of a current mirror circuit 12 is equipped with a pulse generating circuit 20 connected to the other line 1 so that pulse current flows therethrough, and superposing means 30 for superposing a first auxiliary pulse current on the pulse current in synchronization with the rise-up time of the pulse current. The rise-up time is shortened by the superposition. In the driving circuit, a source follower circuit is connected to the current mirror circuit, and current flowing through the source follower circuit is set to be substantially proportional to current flowing through the other line of the current mirror circuit.

Abstract: The present invention is a photonic logic circuit for multimode optical signals. The device includes a laser cavity having at least four conduits, the combination forming a substantially X-shaped construction. An output is attached to each conduit for transmission of the optical signals from the cavity. At least one input is connected to the laser cavity. The input is connected to an upper or lower edge of the laser cavity. These are the edges that do not include conduits. A bias contact is connected to the cavity and the two lower conduits. The bias contact is used to pump the photonic device. Preset contacts are attached to each of the upper two conduits and their respective outputs. The preset contacts are used to control the logic function of the photonic logic device. Altering current pump settings between the respective contacts controls the direction of lasing between outputs of the photonic device and the logic function performed.

Abstract: It is an object of the invention to provide a holographic laser and an optical pickup, with which it is possible to read from and write to a plurality of types of optical disks with different read wavelengths, and to achieve a more compact apparatus. The holographic laser includes for example a package, two semiconductor laser elements and a photodiode for reading out signals accommodated within the package, a holographic element positioned proximate to or in close contact with the top of a glass window, and a wavelength separating element positioned proximate to or in close contact with the top of the holographic element. The holographic laser is integrally formed as a single component.

Abstract: A laser driver for generating drive waveforms that are suitable for driving a single VCSEL or an array of VCSELs. A digital controller is integrated into the laser driver and is utilized to initially program and selectively adjust during the operation of the driver one or more of the following VCSEL drive waveform parameters: (1) bias current, (2) modulation current, (3) negative peaking depth, and (4) negative peaking duration. The laser driver has an aging compensation mechanism for monitoring the age of the laser and for selectively adjusting the dc and ac parameters of the VCSEL drive waveform to compensate for the aging of the laser. The laser driver also has a temperature compensation mechanism for monitoring the temperature of the driver IC and selectively adjusting the dc and ac parameters of the VCSEL drive waveform to compensate for the changes in temperature.

Abstract: A monolthically integrated VCSEL and photodetector, and a method of manufacturing same, are disclosed for applications where the VCSEL and photodetector require separate operation such as duplex serial data communications applications. A first embodiment integrates a VCSEL with an MSM photodetector on a semi-insulating substrate. A second embodiment builds the layers of a p-i-n photodiode on top of layers forming a VCSEL using a standard VCSEL process. The p-i-n layers are etched away in areas where VCSELs are to be formed and left where the photodetectors are to be formed. The VCSELs underlying the photodetectors are inoperable, and serve to recirculate photons back into the photodetector not initially absorbed. The transmit and receive pairs are packaged in a single package for interface to multifiber ferrules. The distance between the devices is precisely defined photolithographically, thereby making alignment easier.

Abstract: The present invention provides a set-reset flip-flop operating in an all-optical manner. In this invention, a set pulse is inputted from the setting port. In doing so, only oscillation in set mode is generated at the multi-mode interference portion in a waveguide. As a result, a non-inverting output Q is obtained from the non-inverting output port. This state is then continued even if the set pulse input goes off. Next, a reset pulse is inputted to the resetting port. In doing so, at the multi-mode interference portion, oscillation of light in the set mode is halted, and oscillation in the reset mode occurs. As a result, it is possible to obtain an inverting output Q-bar from the inverting output port. This state is then continued even if the reset pulse goes off.

Abstract: The invention in question relates to a laser arrangement (1). The device includes the means (2, 4) to steer the laser beam across a reflecting body (3). The body (3) is arranged to reflect the said laser beam so that it is aimed in a surrounding space within an area that, from an instrument plane (11) of the reflecting body (3), covers at least a part of a circular revolution, as well as an angle interval approximately ±60° to the instrument plane. The device is characterized in that its steering means (2, 4) is arranged in the path of the laser beam between the laser (1) and the reflecting body (3), and is arranged to steer the laser beam, within the area, in accordance with a pre-selected direction, whereby the steering means comprises a spatial light modulator (2), whose phase-shift pattern determines the modulated angle from the modulator.

Abstract: This disclosure discusses techniques for obtaining wavelength selected simultaneously super pulsed Q-switched and cavity dumped laser pulses utilizing high optical damage threshold electro-optic modulators, maintaining a zero DC voltage bias on the CdTe electro-optic modulator (EOM) so as to minimize polarization variations depending on the location of the laser beam propagating through the CdSe EOM crystal, as well as the addition of one or more laser amplifiers in a compact package and the use of simultaneous gain switched, Q-switched and cavity dumped operation of CO2 lasers for generating shorter pulses and higher peak power for the hole drilling, engraving and perforation applications.

Abstract: A new class of bistable coupled-resonator vertical-cavity semiconductor laser devices has been developed. These bistable laser devices can be switched, either electrically or optically, between lasing and non-lasing states. A switching signal with a power of a fraction of a milliwatt can change the laser output of such a device by a factor of a hundred, thereby enabling a range of optical switching and data encoding applications.

Abstract: Provided are a source follower circuit having a current source having its improved current characteristics, laser driving apparatus, semiconductor laser apparatus, current-voltage conversion circuit, and light receiving circuit. Each of the laser driving apparatus, semiconductor laser apparatus, current-voltage conversion circuit, and light receiving circuit comprises the source follower circuit. The source follower circuit 10 comprises a source follower stage 12 and a bias stage 14. The source follower stage has III-V compound semiconductor transistors 16, 18 and 20. The bias stage 14 has a first node 22 for providing a first bias voltage and a second node 24 for providing a second biasing voltage different from the first biasing voltage. The gate of transistor 16 is coupled to input 26 and a source thereof is coupled to output 28. The gate of transistor 18 is connected to the second node 24. The gate of transistor 20 is connected to the first node 24.

Abstract: A beam delivery system for a laser emitting at a relevant wavelength of less than 200 nm is provided. The system includes a sealed enclosure connected to the laser and surrounding the path of the beam as it exits the laser resonator. The enclosure extends between the laser output coupler and a photodetector sensitive at the wavelength of the relevant laser emission. The interior of the enclosure, and thus the beam path between the output coupler and the detector, is substantially free of species that strongly photoabsorb radiation at the relevant laser emission wavelength. A beam splitting element diverts at least a portion of the beam for measurement by the detector. The beam splitting element preferably includes a beam splitting mirror, holographic beam sampler or diffraction grating. In addition, optics are preferably provided for filtering a visible portion of the diverted beam, so that substantially only a VUV portion of the diverted beam is received at the detector.

Abstract: The present invention provides an optical multimeter for use in calibrating and testing optical components. The optical multimeter includes an optical analog/digital signal generator for delivering an output beam over a wide range of frequencies, duty cycles and amplitudes. The optical signal generator includes a tunable laser. The tunable laser exhibits a small form factor, due in part to a novel wavelength control process which utilizes an open loop system to maintain precise output wavelength control, without the requirement of either a wavelength or position feedback device.

Abstract: It is an object of the invention to provide a holographic laser and an optical pickup, with which it is possible to read from and write to a plurality of types of optical disks with different read wavelengths, and to achieve a more compact apparatus. The holographic laser includes for example a package, two semiconductor laser elements and a photodiode for reading out signals accommodated within the package, a holographic element positioned proximate to or in close contact with the top of a glass window, and a wavelength separating element positioned proximate to or in close contact with the top of the holographic element. The holographic laser is integrally formed as a single component.

Abstract: A control circuit (10) controls the operation of a laser diode (1) for controlling the average power output (Pav) and the extinction ratio. A state machine (21) controls the control circuit (10) which reads the current from a monitor photo diode (2) which is coupled to the laser diode (1). An amplifier (20) determines the average power output of the laser diode (1) which is fed to a first comparator (23). The first comparator (23) compares the average power output with a reference value set by a resistor (R3). The output from the comparator (23) is fed to the up/down pin of a first counter (25) which is clocked by the state machine (21). In the event that the average power output is too high the first counter (25) decreases the bias current to the laser diode (1) outputted by a constant current source (5), and vice versa.

Abstract: The present invention demodulates a FM, WM or AM optical input beam, amplifies the signal impressed on the beam, and then modulates without intervening electronics the signal amplitude of an output beam. The apparatus can be made from any semiconductor laser, including edge-emitting lasers and VCSELs. Light transmitted through the waveguide (the “control beam”) interacts with the carrier population of the laser, reducing the available gain and thereby the output intensity. The present invention has three key advantages: (i) a FM control beam produces an amplitude-modulated output beam from the main-laser, (ii) the amplitude of the AM beam depends directly on the differential gain ∂G/∂&ohgr;, and (iii) the apparatus and method provides gain for all LOGiC devices. The present invention works with available and future semiconductor lasers, including those emitting in the blue as well as those operating at 670, 850, 980, 1300, and 1500 nm.

Abstract: An arrangement is disclosed for geometrically shaping a radiation field, in particular the radiation field of a diode laser array which propagates in the z direction and has a radiation cross section which is larger, in a direction defined as the y direction, which is perpendicular to the first, and has a lower radiation quality in said direction. X, y and z form a Cartesian coordinate system. The radiation is grouped into radiation fractions in the x direction and the radiation fractions are reoriented as regards their radiation cross sections. The arrangement has at least two reflective elements (6) and is characterized in that each reflective element has a pair of reflection surfaces (7,8) at approximately or exactly 90° to each other. This opening angle (9) is oriented against the direction of propagation. The line (10) at which the reflection surfaces intersect is oriented at approximately below 45° to the x direction.

Abstract: A system contains a laser output measurement circuit used in a laser control system (210). The circuits contain a photodiode sensor (109), sample and hold amplifier (202), IC with synchronizer and delay circuits (206), and an analog to digital converter (204). The circuits measure the laser light output (107) while the laser Module (106) transmits signals. The measurement circuit tracks and stores the laser light output (107) signal using a Photodiode Sensor (109) and with a Sample/hold (202). The methods calculate the value of the laser light output (107) from mathematical relationships, which correlate the light output (107) of the laser Module (106) to the current value of the drive signal (100). Some of the distinguishing features in the present invention are 1) feedback information from the photodiode is obtained in a synchronous manner as a snapshot of the laser performance, and 2) the measurements are precise and calibrated, and 3) no disruption of the signal transmission occurs.