Abstract: A method and an arrangement for producing a workpiece using additive manufacturing techniques involve pre-process, in-process and post-process measurement in order to determine individual characteristics of one or more workpiece layers. In particular, dimensional and/or geometrical characteristics of a workpiece layer are measured before the next workpiece layer is produced. Advantageously, production parameters are controlled in response to individual material characteristics determined prior to the production process. Also advantageously, measurement results are fed back into a production process in order to increase accuracy, reliability, repeatability and precision of the production process.

Abstract: An optical data transmitter having M serially optically connected electro-absorption modulators (EAMs) individually driven using ON-OFF-keying (OOK) electronics, where M is an integer greater than one. In an example embodiment, the optical data transmitter can be used to generate an intensity-modulated optical signal carrying symbols of a 2M-level unipolar pulse-amplitude-modulation constellation. The OOK electronics enables the DC bias voltages and/or AC amplitudes of the two-level drive signals applied to different EAMs to be individually controllable to achieve desired uniform or non-uniform separation between the constellation levels. In at least some embodiments, temperatures of different EAMs may also be individually controllable. In various embodiments, the EAMs may operate in reflection or in transmission.

Abstract: A system comprises an optical heterodyne device, the optical heterodyne device configured to generate an overlap signal based upon: 1) a first optical signal output by a frequency-modulated continuous-wave (FMCW) laser, wherein the first optical signal comprises an optical frequency chirp that is based upon an input voltage signal received by the FMCW laser; and 2) a second optical signal output by a reference laser. The system also includes a photodetector that is optically coupled to the optical heterodyne device, the photodetector configured to output an electrical beat signal based upon the mixing of the optical signals, wherein the electrical beat signal is representative of the mixed down optical signal. The system further includes a frequency analyzer system that generates, based upon the electrical beat signal, data that is indicative of linearity of the optical frequency chirp in the first optical signal.

Abstract: Described herein are isolated ring cavities that have refractive and heat-generating components physically separated and mechanically held by flexure mounts that are adapted to function in combination with the physically separated structure to moderate the thermal expansion effects of the heat generated by the refractive and other heat-generating elements (e.g., gain element) of the optical cavity. The flexure mounts may be configured as thinned portions of connective elements, reducing the effects of thermal expansion of the baseplate and allowing a thermal isolation from the baseplate. Multiple flexure mounts may be arranged to minimize further the effects of thermal expansion of the baseplate.

Abstract: Structures including an edge coupler and methods of fabricating a structure including an edge coupler. The edge coupler includes a waveguide core having an end surface and a tapered section that terminates at the end surface. The tapered section of the waveguide core includes a slab layer and a ridge layer on the slab layer. The slab layer and the ridge layer each terminate at the end surface. The slab layer has a first width dimension with a first width at a given location along a longitudinal axis of the waveguide core, the ridge layer has a second width dimension with a second width at the given location along the longitudinal axis of the waveguide core, and the first width is greater than the second width.

Abstract: An optoelectronic module comprising at least one semiconductor laser and a photonic chip is described herein. The semiconductor laser emits a primary electromagnetic radiation which is coupled into the photonic chip. The photonic chip comprises at least one first waveguide and at least one optical Bragg reflector having a reflectivity which is modulated by an electrical modulation signal. A secondary electromagnetic radiation is coupled out of the photonic chip by means of at least one second waveguide, wherein the secondary electromagnetic radiation has a dominant wavelength which is modulated in dependence of the electrical modulation signal. Further, a method for operating an optoelectronic module and a Head-Mounted Display comprising an optoelectronic module are provided.

Abstract: A system for pumping laser sustained plasma is disclosed. The system includes a plurality of pump modules configured to generate respective pulses of pump illumination for the laser sustained plasma, wherein at least one pump module is configured to generate a train of pump pulses that is interlaced in time with another train of pump pulses generated by at least one other pump module of the plurality of pump modules. The system further includes a plurality of non-collinear illumination paths configured to direct the respective pulses of pump illumination from the plurality of pump modules into a collection volume of the laser sustained plasma.

Abstract: A laser system having a multi-pass amplifier system which includes at least one seed source configured to output at least one seed signal having a seed signal wavelength, at least one pump source configured to output at least one pump signal, at least one multi-pass amplifier system in communication with the seed source and having at least one gain media, a first mirror, and at least a second mirror therein, the gain media device positioned between the first mirror and second mirror and configured to output at least one amplifier output signal having an output wavelength range, the first mirror and second mirror may be configured to reflect the amplifier output signal within the output wavelength range, and at least one optical system may be in communication with the amplifier system and configured to receive the amplifier output signal and output an output signal within the output wavelength range.

Abstract: A light source providing tunable light of macroscopic power, particularly by utilizing a broadband pump source, an optical parametric oscillator (OPO) and at least one additional nonlinear process. The light source is capable of producing a tunable broadband emission of macroscopic power, particularly at wavelengths less than 1.1 ?m.

Abstract: The present invention relates to a method for detecting steel sample components by using a multi-pulse laser induced plasma spectral analysis device, and in particular, to a method for detecting steel sample components by using a multi-pulse laser induced plasma spectral analysis device that includes picosecond and nanosecond laser pulse widths. A laser induced light source is a laser light source that includes nanosecond and picosecond ultrashort pulses, and one pulse laser device can be used to generate two pulse lasers, namely, a nanosecond and a picosecond laser; the two pulse lasers pass through a same output and focusing light path, so as to ensure that the two pulse lasers are focused on a same position of a sample to be detected; a surface of the sample is irradiated by using a first beam of nanosecond laser pulse to generate plasmas; subsequently, the plasmas are irradiated by using a second beam of picosecond laser pulse to enhance spectral line emission.

Abstract: A terahertz wave generation apparatus includes a plurality of laser light sources configured to generate laser beams respectively having different wavelengths; and a terahertz wave generating element configured to receive the laser beams having different wavelengths and generate a terahertz wave from the laser beams. The plurality of laser light sources include fiber laser light sources respectively including parameters that can be controlled independently, and the terahertz wave generating element includes a nonlinear optical crystal.

Abstract: The present invention relates to a system for modulating laser pulses by means of an electro-optical modulator which is operated by means of a pulsed modulation voltage. A voltage converter mounted upstream of the modulator converts a pulsed modulated switching voltage at an output voltage level to the modulation voltage that is higher than the output voltage level. The invention further relates to a method for modulating laser pulses.

Abstract: The invention relates to a marking apparatus for marking an object with laser light, which apparatus comprises at least one gas laser for emitting at least one laser beam for marking the object. The at least one gas laser comprises a plurality of resonator tubes (12) for receiving a laser gas, a plurality of heat dissipaters (20) for dissipating heat from the resonator tubes (12) is provided, each resonator tube (12) is thermally connected to one of the heat dissipaters (20), and each heat dissipater (20) comprises microchannels for receiving a cooling fluid.

Abstract: An adaptive laser system for ophthalmic use is provided. In another aspect, a relatively inexpensive laser is employed. In another aspect of the present system, non-linear optical imaging uses multiphoton fluorescences and/or second harmonic generation, to create three-dimensional mapping of a portion of the eye in combination with automated feedback to assist with a surgical operation. In a further aspect of the present system, the patient interface uses laser induced markings or indicia to aid in focusing and/or calibration. Still another aspect employs temporal focusing of the laser beam pulse.

Abstract: A modulated semiconductor laser source includes a waveguide on a semiconductor substrate; first and second reflectors; a laser electrode; an optical modulator; and a laser-electrode electrical circuit. The reflectors and a resonator segment of the waveguide define a laser resonator with laser output transmitted through the second reflector. The laser electrode is positioned over the resonator segment and a laser current flows through the laser electrode into the resonator segment to produce optical gain. The modulator receives and modulates the laser output, in response to a primary modulation signal, to produce a modulated output optical signal. The laser-electrode circuit is coupled to the laser electrode and derives from the primary modulation signal a laser-electrode secondary modulation current, optimized to reduce chirp in the modulated output signal, that flows through the laser electrode into or out of the resonator segment in addition to the laser current.

Abstract: An optical module includes: a first thermoelectric cooler (TEC) disposed at least partially inside a laser, a second TEC is disposed on a housing of the laser, and a micro control unit (MCU). The first TEC is configured to perform heating or cooling according to an enabling signal input by a MCU. The second TEC is configured to perform heating or cooling according to an enabling signal input by the MCU. The MCU is configured to determine whether to input an enabling signal or a disabling signal to the first TEC and the second TEC according to a size of operating current input by a drive circuit of a laser chip to the laser chip.

Abstract: A system and method for stabilizing and combining multiple emitted beams into a single system using both WBC and WDM techniques.

Abstract: Disclosed herein is a single pulse laser apparatus that includes: a resonator having a first mirror, a second mirror, a gain medium, an electro-optic modulator (EOM) configured to perform single pulse switching, and an acousto-optic modulator (AOM) configured to perform mode-locking; a photodiode configured to measure a laser beam oscillated in the resonator; a synchronizer configured to convert an electrical signal, which is generated by measuring the laser beam, into a transistor-transistor logic (TTL) signal; a delay unit configured to set a delay time for the TTL signal to synchronize the EOM and the AOM and output a trigger TTL signal according to the delay time; an AOM driver configured to input the trigger TTL signal to the AOM that performs mode-locking and drive the AOM; and an EOM driver configured to input the trigger TTL signal to the EOM that performs single pulse switching and drive the EOM.

Abstract: Apparatuses and methods are disclosed for applying laser energy having desired pulse characteristics, including a sufficiently short duration and/or a sufficiently high energy for the photomechanical treatment of skin pigmentations and pigmented lesions, both naturally-occurring (e.g., birthmarks), as well as artificial (e.g., tattoos). The laser energy may be generated with an apparatus having a resonator with the capability of switching between a modelocked pulse operating mode and an amplification operating mode. The operating modes are carried out through the application of a time-dependent bias voltage, having waveforms as described herein, to an electro-optical device positioned along the optical axis of the resonator.

Abstract: The invention relates to a marking apparatus (100) for marking an object with laser light, comprising a plurality of lasers (10), in particular gas lasers (10), and a control unit for individually activating each of the lasers (10) to emit a laser beam according to a sign to be marked. A deflection device (30) is provided by which at least two laser beams are combined on a common spot.

Abstract: The invention relates to a marking apparatus for marking an object with laser light, comprising a plurality of lasers and a control unit for individually activating each of the lasers to emit a laser beam (90) according to a sign to be marked. A set of deflection means (30) for rearranging the laser beams (90) into a desired array of laser beams (90) is provided, the set of deflection means (30) comprises at least two deflection means (33a-i, 34a-i) per laser beam (90), in particular at least two mapping mirrors (33a-i, 34a-i) or at least one optical waveguide and one lens per laser beam (90a-i), and each deflection means (33a-i, 34a-i) is individually adjustable in its deflection direction and/or individually shiftable.

Abstract: The invention relates to a marking apparatus (100) for marking an object with laser light, comprising a plurality of gas lasers (10) and a control unit for individually activating each of the gas lasers (10) to emit a laser beam according to a sign to be marked. The gas lasers (10) are stacked such that the laser beams emitted by the gas lasers (10) form an array of laser beams, in particular a linear array with parallel laser beams, each gas laser (10a-i) comprises laser tubes (12) that at least partially surround an inner area (5). The apparatus (100) further comprises beam-delivery means (14) for directing the array of laser beams into the inner area (5) and a set of deflection means (30) for rearranging the array of laser beams into a desired array of laser beams. The set of deflection means (30) is arranged in the inner area (5) and comprises at least one deflection means (33a, 33i) per laser beam, in particular at least one mapping mirror (33a, 33i) or one optical waveguide per laser beam.

Abstract: The invention relates to a marking apparatus for marking an object with laser light, comprising a plurality of lasers and a control unit for individually activating each of the lasers to emit a laser beam (90a-i) according to a sign to be marked. A set of deflection means (30) for directing the laser beams (90a-i) toward the object to be marked is provided, a set of telescopic means (40) comprising at least one telescopic means (40a-i) per laser beam (90a-i) is provided, and each telescopic means (40a-i) is adjustable for individually setting a focal length of the respective laser beam (90a-i).

Abstract: According to a first aspect of the present invention, there is provided a radiation source comprising: a nozzle configured to direct a stream of fuel droplets (70) along a trajectory towards a plasma formation location; a laser configured to direct laser radiation at a fuel droplet at the plasma formation location to generate, in use, a radiation generating plasma; wherein the laser comprises: a seed laser (50) for providing a seed laser beam (52); a beam splitter (54) for receiving the seed laser beam from the seed laser; an optical amplifier (58) for receiving the seed laser beam from the beam splitter and performing optical amplification; a first reflector (60) located downstream of the optical amplifier, configured to direct the seed laser beam back through the optical amplifier and on to the beam splitter; and a second reflector (70) located further downstream of the beam splitter, configured to receive the seed laser beam from the beam splitter and to direct at least a portion of the seed laser beam bac

Abstract: The present disclosure discloses a CO2 laser and a method for the CO2 laser. The CO2 laser comprises an unstable laser cavity in the form of a first optical resonator having a semi-transparent output coupler (3), a laser medium (2) in the unstable laser cavity, and means (1) for exciting the laser medium (2). A part of the laser beam propagating beyond the light aperture of the output coupler (3) is directed to a second resonator, the second resonator comprising at least one focusing member (6), and the optical length of the second resonator being equal or multiple to the optical length of the first optical resonator. The part of the laser beam passing through the focal plane of the focusing member (6) is modulated by using a Q-switching device (8) in a manner that the excitation of the laser medium is in synchrony with the operation of the Q-switching device (8).

Abstract: System and methods for producing a plurality of Sinc shaped pulses in the time domain include a light source for providing an input light signal having an input frequency, and at least one spectrum shaper for producing the plurality of Sinc shaped pulses from the input light signal. The spectrum shaper may include an amplitude modulator, at least one radio-frequency generator and a bias voltage generator.

Abstract: This invention provides a solution for operating a regenerative amplifier using a single electro-optical device, such as a Pockels cell. An efficient cavity geometry of a regenerative amplifier is provided for enabling pulse selection, coupling and releasing to an output by operating a single Pockels cell unit placed essentially in the middle of the optical cavity, between two polarizers, whereas a first polarizer is used for release of an amplified pulse and a second polarizer is used for injection of seed pulses and release of at least one of waste amplified pulses and seed pulses. One side of the cavity, with respect to the location of said Pockels cell, includes an empty space, whereas the other side is provided with a gain medium, which is pumped by a pump source. The regenerative amplifier of such optical design is both efficient and cost effective. The single electro-optical unit works both as the control unit for operating the regenerative amplifier and as an output pulse picker unit.

Abstract: Technologies are described for enabling VCSELs to transmit phase or frequency modulated signals, which may have a substantially smaller transmission bandwidth and are more robust to transmission in a highly dispersive media such as multi-mode fibers. By applying an electric, magnetic, or electromagnetic field across one or more reflector layers of the VCSEL, a refractive index of the reflector layer(s) may be modified. The VCSEL may then be excited and the laser beam generated by the VCSEL phase-modulated by modifying a magnitude of the applied field.

Abstract: A target marking system includes a light source emitting a thermal beam and an optics assembly directing the thermal beam to impact a target, the target directing radiation to the optics assembly in response to the impact. The target marking system further includes a detector, and an optics assembly optically connected to the detector.

Abstract: A laser apparatus and method are provided for generating optical pulses based on Q-switching controllable with a fast and reliable two-dimensional (2-D) spatial light modulator, such as a digital micro-mirror device (DMD). Temporal and spatial modulation may be applied to selectively control the Q-switching provided by the spatial light modulator. The apparatus and method may be optionally optimized with straightforward optical components to increase angular magnification of a beam incident on the spatial light modulator and thus effectively reduce the Q-switching time.

Abstract: An apparatus, method and system that uses a Q-switched laser or a Q-seed source for a seed pulse signal having a controlled high-dynamic-range amplitude that avoids and/or compensates for pulse steepening in high-gain optical-fiber and/or optical-rod amplification of optical pulses. Optionally, the optical output is used for LIDAR or illumination purposes (e.g., for image acquisition). In some embodiments, well-controlled pulse shapes are obtained having a wide dynamic range, long duration, and not-too-narrow linewidth. In some embodiments, upon the opening of a Q-switch in an optical cavity having a gain medium, the amplification builds relatively slowly, wherein each round trip through the gain medium increases the amplitude of the optical pulse. Other embodiments use quasi-Q-switch devices or a plurality of amplitude modulators to obtain Q-seed pulses.

Abstract: Used is an object information acquiring apparatus including an irradiation unit for irradiating an object with a laser beam, a wavelength switching unit for selecting a wavelength of the laser beam, a restriction unit for restricting an output value of the laser beam, a probe for receiving acoustic waves that are generated from the object irradiated with the laser beam, and a configuration unit for generating characteristic information relating to the object in use of the acoustic waves, wherein the restriction unit restricts the output value according to the wavelength selected by the wavelength switching unit.

Abstract: In a method for operating a laser system in a Q-switched mode, the laser system provided with a laser resonator with a laser medium and an electro-optical modulator, wherein the electro-optical modulator has an EOM crystal, wherein the EOM crystal has a characteristic ringing time (t0) when subjected to acoustic ringing, the EOM crystal is driven by modulator voltage pulses (pm) having a modulator voltage pulse duration (tml). A train of at least two subsequent laser pulses (pl) is generated. The modulator voltage pulse duration (tml)is selected to be at least approximately equal to the characteristic ringing time (t0) of the EOM crystal multiplied by an integer factor.

Abstract: A method, apparatus and computer-readable storage medium are described for a tunable laser source that produces a desired frequency modulated optical waveform with a precision within 0.01 percent over a bandwidth greater than about 50 gigaHertz. An apparatus includes a tunable laser having one or more drive inputs for affecting an optical frequency of light output by the laser; and an optical detector. Multiple optical paths are configured to direct light output by the laser onto the optical detector. A laser controller is configured to provide to a drive input a loopback signal based on a measured or predetermined difference in optical dispersion among the plurality of optical paths and a detector signal output from the optical detector. In some embodiments, a ranging device includes the tunable laser source.

Abstract: A system and method for controllably chirping electromagnetic radiation from a radiation source includes an optical cavity arrangement. The optical cavity arrangement enables electromagnetic radiation to be produced with a substantially linear chirp rate and a configurable period. By selectively injecting electromagnetic radiation into the optical cavity, the electromagnetic radiation may be produced with a single resonant mode that is frequency shifted at the substantially linear chirp rate. Producing the electromagnetic radiation with a single resonant mode may increase the coherence length of the electromagnetic radiation, which may be advantageous when the electromagnetic radiation is implemented in various applications. For example, the electromagnetic radiation produced by the optical cavity arrangement may enhance a range, speed, accuracy, and/or other aspects of a laser radar system.

Abstract: A method and apparatus for stabilizing the seed laser in a laser produced plasma (LPP) extreme ultraviolet (EUV) light system are disclosed. In one embodiment, the cavity length of the laser may be adjusted by means of a movable mirror forming one end of the cavity. The time delay from the release of an output pulse to the lasing threshold next being reached is measured at different mirror positions, and a mirror position selected which results in a cavity mode being aligned with the gain peak of the laser, thus producing a minimum time delay from an output pulse of the laser to the next lasing threshold. A Q-switch in the laser allows for pre-lasing and thus jitter-free timing of output pulses. Feedback loops keep the laser output at maximum gain and efficiency, and the attenuation and timing at a desired operating point.

Abstract: A system for generating multiple simultaneous laser wavelengths, said system comprising: a pulsed slave laser comprising a non-linear electro-optic crystal optically coupled to a lasing crystal in a ring cavity configuration, said non-linear electro-optic crystal configured to adjust an optical path length of said ring cavity in response to an applied voltage potential; an energy pump configured to initiate a pulse cycle in said pulsed slave laser in response to a trigger; a cavity control circuit configured to apply said voltage potential to said non-linear electro-optic crystal to generate a cavity resonance condition associated with said adjusted optical path length, said cavity control circuit further configured to provide said trigger to said energy pump in response to a detection of said cavity resonance condition; and one or more seed lasers configured to inject a single frequency laser beam into said pulsed slave laser.

Abstract: Loss modulated silicon evanescent lasers are disclosed. A loss-modulated semiconductor laser device in accordance with one or more embodiments of the present invention comprises a semiconductor-on-insulator (SOI) structure resident on a first substrate, the SOI structure comprising a waveguide in a semiconductor layer of the SOI structure, and a semiconductor structure bonded to the semiconductor layer of the SOI structure, wherein at least one region in the semiconductor layer of the SOI structure controls a photon lifetime in the semiconductor laser device.

Abstract: A vertical cavity surface emitting laser (VCSEL) system and method of fabrication are included. The VCSEL system includes a gain region to amplify an optical signal in response to a data signal and a first mirror arranged as a partially-reflective high-contrast grating (HCG) mirror at an optical output of the VCSEL system. The VCSEL system also includes a second mirror. The first and second mirrors can be arranged as a laser cavity to resonate the optical signal. The VCSEL system further includes a doped semiconductor region to generate a current through the first mirror in response to a voltage signal to substantially alter the reflectivity of the first mirror to provide Q-switching capability of the VCSEL system.

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

Abstract: A system for generating multiple simultaneous laser wavelengths, said system comprising: a pulsed slave laser comprising a non-linear electro-optic crystal optically coupled to a lasing crystal in a ring cavity configuration, said non-linear electro-optic crystal configured to adjust an optical path length of said ring cavity in response to an applied voltage potential; an energy pump configured to initiate a pulse cycle in said pulsed slave laser in response to a trigger; a cavity control circuit configured to apply said voltage potential to said non-linear electro-optic crystal to generate a cavity resonance condition associated with said adjusted optical path length, said cavity control circuit further configured to provide said trigger to said energy pump in response to a detection of said cavity resonance condition; and one or more seed lasers configured to inject a single frequency laser beam into said pulsed slave laser.

Abstract: A laser device suitable for emitting pulses with a variable period and with stabilized energy includes: a resonant cavity including an amplifying medium presenting a stabilized gain G and suitable for emitting laser pulses at a wavelength ?, and a Q-switch, and a source of continuous pumping of the amplifying medium. It furthermore includes an injector positioned outside the resonant cavity, suitable for emitting a beam of wavelength ? into the amplifying material for the duration of the pumping, and which includes means for adjusting the power of this beam in order to reduce the gain of the amplifying medium to G/k, where k is a real number greater than 1.

Abstract: An actively Q-switched laser based on UV illumination mitigates pyroelectric effects in lithium niobate. An exemplary embodiment comprises a pump source; a dichroic mirror having one end optically facing said pump source; a gain medium optically facing another end of said dichroic mirror; a polarizer having one end optically facing another end of said gain medium; a quarter wave plate having one end optically facing another end of said polarizer; and a electro-optic crystal having one end optically facing said quarter wave plate, at least one side of said electro-optic crystal being electrically connected to Q-switch driver to have the crystal function as a Q-switch. A UV illumination source illuminates a side surface of said electrical-optic crystal with UV light. An output mirror receives an output from said Q-switch and produces a laser emission.

Abstract: A method for obtaining high-energy, high repetition rate laser pulses simultaneously using continuous wave (CW) amplifiers is described. The method provides for generating micro-joule level energy in pico-second laser pulses at Mega-hertz repetition rates.

Abstract: A laser device of an equal-energy pulse synchronous with motion includes: a resonant cavity, outputting a plurality of pulses with stable pulse-width and energy; a beam switch modulator, selectively enabling one of the pulses to pass; a beam energy modulator, adjusting the energy of the pulse according to a power feedback signal; an optical power sensor, sensing the energy and the pulse-width of the pulse; a motion controller, providing processing motion information; an optical feedback controller, outputting the power feedback signal to the beam energy modulator according to the energy of the pulse and the processing motion information; a trigger controller, measuring a time difference between time when the pulse is triggered and time when the optical power sensor detects the pulse, and correcting a turn-on time point of the beam switch modulator. The processing quality is therefore stabilized, and the device is applicable to various laser industrial processes.

Abstract: An array of light valves switch light by enabling and disabling total internal reflection (TIR) on a surface of the light valve. The disabling of the TIR is accomplished by putting another optical element in contact with the surface and then diffusing or changing the direction of the light. The mechanical mechanism to move the optical element is a simple one in that it only moves the optical element a small distance to change the valve from a first position to a second position.

Abstract: An optical clock comprises a laser oscillator and modulating means arranged to cooperate with the laser oscillator to produce a series a series of phase-modulated optical pulses. The optical clock further comprises an optical fiber arranged to provide compression of the optical pulses, and may also comprise a step-recovery diode arranged to pulse-pick pulses output from the fiber to produce a series of optical clock pulses, depending on the mode of operation of the modulating means. Phase-modulation is carried out a frequency which provides sufficient linewidth broadening to inhibit stimulated Brillouin scattering within the optical fiber. An optical clock of the invention provides a robust and reliable alternative to clocks based on modelocked lasers, and may be assembled from inexpensive, commonly-available components. The repetition rate of a clock of the invention may easily be adjusted by electronic means. Unlike many modelocked lasers, a clock of the invention does not require precise optical alignment.

Abstract: To make it possible to use a type I nonlinear optical crystal or a quasi phase matching element as a third harmonic generation crystal there is provided a semiconductor laser, a solid state laser medium that outputs a fundamental wave, a second harmonic generation crystal that outputs a second harmonic wave from the fundamental wave, and a third harmonic generation crystal that outputs a third harmonic wave from the fundamental wave and the second harmonic wave. A quasi phase matching elements is utilized as the second harmonic generation crystal. It is possible to use a type I nonlinear optical crystal or a quasi phase matching element as the third harmonic generation crystal.

Abstract: Certain embodiments of the invention may include systems, methods, and apparatus for generating terahertz electromagnetic radiation. According to an example embodiment of the invention, a method is provided for generating terahertz electromagnetic radiation. The method includes: coupling a terahertz resonator with an optical resonator, wherein the optical resonator comprises non-linear optical material; directing laser light through the optical resonator to generate terahertz radiation by parametric interaction of the laser light with the optical resonator and the terahertz resonator; and directing the terahertz radiation from the terahertz resonator to an output.

Abstract: A device contains at least one wavelength-tunable multilayer interference reflector controlled by an applied voltage and at least one cavity. The stopband edge wavelength of the wavelength-tunable multilayer interference reflector is preferably electrooptically tuned using the quantum confined Stark effect in the vicinity of the cavity mode (or a composite cavity mode), resulting in a modulated transmittance of the multilayer interference reflector. A light-emitting medium is preferably introduced in the cavity or in one of the cavities permitting the optoelectronic device to work as an intensity-modulated light-emitting diode or diode laser by applying an injection current. The device preferably contains at least three electric contacts to apply forward or reverse bias and may operate as a vertical cavity surface-emitting light emitter or modulator or as an edge-emitting light emitter or modulator.