Abstract: A system and method for tuning and infrared source laser in the Mid-IR wavelength range. The system and method comprising, at least, a plurality of individually tunable emitters, each emitter emitting a beam having a unique wavelength, a grating, a mirror positioned after the grating to receive at least one refracted order of light of at least one beam and to redirect the beam back towards the grating, and a micro-electro-mechanical systems device containing a plurality of adjustable micro-mirrors.

Abstract: A wavelength tunable laser device includes a gain element positioned in an optical cavity that provides optical gain to an optical signal. A frequency shifter that generates a frequency shift as a function of time is positioned in the optical cavity. The optical cavity is configured so that a magnitude of the frequency shift as a function of time generated by the frequency shifter is substantially equal to a frequency separation of a cavity mode of the cavity such that an output of the cavity generates laser light having a wavelength that tunes as a function of time.

Abstract: An injection locked transmitter for an optical communication network includes a master seed laser source input substantially confined to a single longitudinal mode, an input data stream, and a laser injected modulator including at least one slave laser having a resonator frequency that is injection locked to a frequency of the single longitudinal mode of the master seed laser source. The laser injected modulator is configured to receive the master seed laser source input and the input data stream, and output a laser modulated data stream.

Abstract: A waveguide gas laser having a laser resonator cavity of a variable length is subjected to cyclical varying of the length of the cavity during generation of a laser beam a length variation amount sufficient to force a laser beam generated in the resonator cavity though a substantially complete optical longitudinal cavity mode at a rate operable to smooth at least one laser beam parameter variation. In this manner variation in the laser beam parameter is averaged by moving through at least a portion of an optical longitudinal cavity mode.

Abstract: In various embodiments, monitoring of one or more secondary diffracted beams formed within a laser resonator provides information based at least in part on which a primary diffracted beam formed within the laser resonator is controlled.

Abstract: A laser system, comprised of: a laser cavity; a gain medium a pump, a saturable absorber (SA); a first mirror and a second mirror; wherein a ratio of an area of the beam area within the SA to an area of the laser beam within the gain medium is greater than 1, and wherein the beam generates a gain medium radius spot on the gain medium and a saturable absorber radius spot on the saturable absorber such that a ratio between a saturable absorber radius spot on the saturable absorber and the gain medium radius spot on the gain medium is within a range of 1.7-7 is disclosed. A method for using the laser system e.g., for producing a pulsed energy is further disclosed.

Abstract: An apparatus can be provided which can include a laser arrangement which can be configured to provide a laser radiation, and can include an optical cavity. The optical cavity can include a dispersive optical first arrangement which can be configured to receive and disperse at least one first electro-magnetic radiation so as to provide at least one second electro-magnetic radiation. Such cavity can also include an active optical modulator second arrangement which can be configured to receive and modulate the at least one second radiation so as to provide at least one third electro-magnetic radiation. The optical cavity can further include a dispersive optical third arrangement which can be configured to receive and disperse at least one third electro-magnetic radiation so as to provide at least one fourth electro-magnetic radiation.

Abstract: A laser device includes a wavelength-tunable laser including plural wavelength selectors in an optical resonator; a semiconductor optical amplifier that amplifies the laser light input thereto; a light intensity variation detector that detects variation in intensity of the laser light output from the wavelength-tunable laser before the laser light is input to the semiconductor optical amplifier; a wavelength dithering generation unit that generates a resonator mode wavelength dithering to modulate a resonator mode of the resonator; a wavelength dithering feedback controller that performs, on the resonator mode wavelength dithering, feedback control based on the variation in intensity detected by the light intensity variation detector; a light intensity detector that detects an intensity of the laser light output from the semiconductor optical amplifier; and a semiconductor optical amplifier feedback controller that performs feedback control on the semiconductor optical amplifier based on the intensity detecte

Abstract: An injection locked transmitter for an optical communication network includes a master seed laser source input substantially confined to a single longitudinal mode, an input data stream, and a laser injected modulator including at least one slave laser having a resonator frequency that is injection locked to a frequency of the single longitudinal mode of the master seed laser source. The laser injected modulator is configured to receive the master seed laser source input and the input data stream, and output a laser modulated data stream.

Abstract: An injection locked transmitter for an optical communication network includes a master seed laser source input substantially confined to a single longitudinal mode, an input data stream, and a laser injected modulator including at least one slave laser having a resonator frequency that is injection locked to a frequency of the single longitudinal mode of the master seed laser source. The laser injected modulator is configured to receive the master seed laser source input and the input data stream, and output a laser modulated data stream.

Abstract: Inspecting a multilayer sample may include receiving, at a beam splitter, light and splitting the light into first and second portions; combining, at the beam splitter, the first portion of the light after being reflected from a multilayer sample and the second portion of the light after being reflected from a reflector; receiving, at a computer-controlled system for analyzing Fabry-Perot fringes, the combined light and spectrally analyzing the combined light to determine a value of a total power impinging a slit of the system for analyzing Fabry-Perot fringes; determining an optical path difference (OPD); recording an interferogram that plots the value versus the OPD for the OPD; performing the previous acts of the method one or more additional times with a different OPD; and using the interferogram for each of the different OPDs to determine the thicknesses and order of the layers of the multilayer sample.

Abstract: Embodiments of this application disclose an ODU and a transmit power control method for an ODU. The ODU includes a controller, a radio frequency processor, a waveguide channel, an antenna, a wave-absorbing block, a detector, and a motor controller. The controller is configured to obtain target transmit power, first transmit power, and a to-be-transmitted first radio frequency signal, and generate a control signal based on a difference between the target transmit power and the first transmit power. The radio frequency processor is configured to: perform frequency conversion on the first radio frequency signal to obtain the second radio frequency signal, and transmit the second radio frequency signal, where the second radio frequency signal is transmitted to the antenna through the waveguide channel. The wave-absorbing block has one end located in the waveguide channel and the other end connected to the motor controller.

Abstract: Apparatus include an optical cavity including an optical coupling portion situated to couple an optical signal input field to an intracavity optical signal field and an optical control input field to an intracavity optical control field, wherein the optical cavity includes a nonlinear optical medium that mediates a selective exchange of at least one predetermined temporal mode between the intracavity optical signal field and an intracavity optical register field based on a nonlinear phase-matched interaction between the intracavity optical signal, control, and register fields and selectable field characteristics of the optical control input field.

Abstract: A laser device includes a laser medium for amplifying seed light, a first optical system for outputting excitation light for exciting the laser medium and causing the excitation light to be incident on the laser medium and input to an excitation region of the laser medium, and a second optical system for causing the seed light of first polarization to be incident on the laser medium at an incidence angle larger than 0° with respect to the laser medium and input to the excitation region.

Abstract: The present disclosure relates optical imaging devices and methods useful in biological and medical imaging applications. In one embodiment, an optical imaging device includes a flexible lightguide having a first end and a second end, the output of the source of pulsed infrared radiation being optically coupled to the first end of the flexible lightguide; a lens assembly attached to and optically coupled to the second end of the flexible lightguide, the lens assembly comprising a variable-focus lens element, the a variable-focus lens element having a tunable focal length; and a photodetector coupled to the flexible lightguide to detect radiation propagating from the second end toward the first end of the flexible lightguide. The optical imaging devices and methods can be used in both confocal and multi-photon techniques.

Abstract: An injection locked transmitter for an optical communication network includes a master seed laser source input substantially confined to a single longitudinal mode, an input data stream, and a laser injected modulator including at least one slave laser having a resonator frequency that is injection locked to a frequency of the single longitudinal mode of the master seed laser source. The laser injected modulator is configured to receive the master seed laser source input and the input data stream, and output a laser modulated data stream.

Abstract: A mode-locked laser comprising circuitry configured to drive an electro-optic modulator (EOM) in the mode-locked laser with a drive waveform, the drive waveform being a phase-coherent sinusoidal waveform at a frequency equal to a repetition rate of the mode-locked laser, a phase-coherent pulsed waveform at a frequency equal to the repetition rate of the mode-locked laser, or a phase-coherent sinusoidal waveform at a frequency equal to half of the repetition rate of the mode-locked laser.

Abstract: A method of cutting a semiconductor material by irradiating the semiconductor material with laser energy, includes providing a laser source adapted to emit successive pulses of laser beams, each laser beam pulse having a pulse width of 100 picoseconds or less, emitting laser beam pulses from the laser source, guiding the emitted laser beam pulses to irradiate semiconductor material to be cut, and moving the semiconductor material relative to the irradiating laser beam pulses to cut the semiconductor material along a cutting line. The semiconductor material is irradiated by a plurality of laser beam pulses with a pulse repetition frequency in the range from 0.1 GHz to 5000 GHz.

Abstract: A femtosecond laser oscillator includes a 532 nm pump laser light, a Ti-doped sapphire, a laser resonator, and a dispersion compensation element, etc. The 532 nm pump laser light is radiated via a pump laser light guide device to the Ti-doped sapphire and generates stimulated radiation, the stimulated radiation light oscillates back and forth in the laser resonator and thereby is amplified, and continuous light is outputted. The dispersion compensation element is disposed in the resonator to compensate the dispersion of the outputted laser light resulted from oscillation of the laser light in the resonator to attain a mode locking condition. The mode locking means of the laser against disturbance is implemented in a form of return light outside the resonator, specifically, the emitted continuous light is returned to a femtosecond laser partially and thereby mode locking is achieved, and output of femtosecond pulses is realized.

Abstract: A tunable electro-optic modulation (EOM) comb generator includes a frequency locking optoelectronic oscillator (OEO) loop including RF electrical components including a phase shifter (PS1), a splitter, and optical components including an intensity modulator (IM) coupled to receive light from a light source and to couple modulated light generated to a frequency locking loop including a frequency shifter, a first phase modulator (PM1), and a periodic optical filter (POF), such as an etalon or resonator. The POF is for optically filtering the OEO loop to generate an optical output and the splitter is for generating RF electrical outputs including at least one RF output coupled to an input of the IM and another RF output coupled to an EO comb including at least a phase modulator. The EO comb combines the optical output and the another RF output to generate a broadband optical frequency comb output.

Abstract: Examples of light projector systems for directing input light from a light source to a spatial light modulator are provided. For example, an optical device is disclosed which includes a first surface having a diffractive optical element, a second surface normal to the first surface, and a third surface arranged at an angle to the second surface. The third surface may be a beam splitting surface that is reflective to light of a first state and transmissive to light of a second state. The diffractive optical element may receive an input beam made up of light having the first state, and convert the input beam into at least a first diffracted beam at a first diffraction angle such that the first diffracted beam is directed toward the third surface and is reflected by the third surface in a direction substantially parallel to the first surface.

Abstract: A high-power ytterbium-doped calcium fluoride laser system is disclosed herein which includes at least one pump source, at least one laser cavity formed by at least one high reflector and at least one output coupler, and at least one ytterbium-doped calcium fluoride optical crystal positioned within the laser cavity in communication with the pump source, the ytterbium-doped calcium fluoride optical crystal configured to output at least one output signal of at least 20 W, having a pulse width of 200 fs or less, and a repetition rate of at least 40 MHz.

Abstract: A mode locking semiconductor disk laser (SDL) comprising a resonator terminated by first and second mirrors and folded by a third mirror is presented. The third mirror includes a semiconductor disk laser (SDL) suitable for generating a resonator field having a predetermined central wavelength ?0, while the second mirror includes an intensity saturable mirror suitable for mode locking the resonator field at the predetermined wavelength. The central wavelength of the reflectivity profile of the first and or second mirrors is shifted to a wavelength shorter than the central wavelength ?0 to suppress gain at wavelengths longer than the central wavelength ?0. By mismatching the reflectivity profile of the first and or second mirrors to that of the desired output wavelength provides a stable mode locked laser with significantly reduced noise.

Abstract: Example embodiments relate to an electro-optical device that includes a vertical p-i-n diode waveguide. The electro-optical device includes a waveguide portion adapted for propagating a multimode wave, the waveguide portion including an intrinsic semiconductor region of the vertical p-i-n diode, a first contact and a second contact for electrically contacting a first electrode and a second electrode of the vertical p-i-n diode. The device also includes an input section for coupling radiation into the waveguide portion and an output section for coupling radiation out of the waveguide portion. The input section, the output section, and the waveguide portion are configured to support a multimode interference pattern for the multimode wave with an optical field with a lateral inhomogeneous spatial distribution in the waveguide portion including regions with higher optical field intensity and regions with lower optical field intensity. The second contact physically contacts the second electrode.

Abstract: An injection locked transmitter for an optical communication network includes a master seed laser source input substantially confined to a single longitudinal mode, an input data stream, and a laser injected modulator including at least one slave laser having a resonator frequency that is injection locked to a frequency of the single longitudinal mode of the master seed laser source. The laser injected modulator is configured to receive the master seed laser source input and the input data stream, and output a laser modulated data stream.

Abstract: One example includes an optical transmitter system. The system includes a waveguide to receive and propagate an optical signal. The system also includes a ring modulation system comprising a ring resonator that is optically coupled to the waveguide and is to resonate a given wavelength of the optical signal in response to an input data signal that is provided to a modulation amplifier to provide carrier injection to change a refractive index of the ring resonator to resonate the given wavelength of the optical signal to modulate the optical signal. The system further includes a tuning controller associated with the ring modulation system. The tuning controller can implement iterative feedback tuning of the ring modulation system based on a relative amplitude of an optical intensity of the given wavelength in the ring resonator and a variable reference amplitude to substantially stabilize the ring resonator with respect to the given wavelength.

Abstract: A mode-locked fiber laser device is provided in the disclosure. The mode-locked fiber laser device includes a non-linear loop mirror, an optical splitter and a uni-directional loop. The uni-directional loop includes a polarization beam splitter and a Faraday rotator. The uni-directional loop is coupled to the non-linear loop mirror by the optical splitter to form a figure-8 optical path. A first output laser pulse output by the optical splitter is propagated to the polarization beam splitter. After being rotated 45 degrees by a Faraday rotator, the first output laser pulse is propagated back to the non-linear loop mirror to form a laser resonator. A second output laser pulse output by the optical splitter is propagated to the Faraday rotator to rotate the second output laser pulse 45 degrees, and the polarization beam splitter reflects the second output laser pulse to the outside of the mode-locked fiber laser device.

Abstract: Direct diode-pumped Ti:sapphire laser amplifiers use fiber-coupled laser diodes as pump beam sources. The pump beam may be polarized or non-polarized. Light at wavelengths below 527 nm may be used in cryogenic configurations. Multiple diode outputs may be polarization or spectrally combined.

Abstract: Disclosed is a method of welding dissimilar metals, including: preparing a dissimilar metal bus bar composed of a plate-shaped first member made of a first metal and a plate-shaped second member made of a second metal disposed under the first member; folding one side of the dissimilar metal bus bar so that a portion of the second member is located on a portion of the first member; welding a lead made of the first metal on the first member; and welding a lead made of the second metal to the second member located on the portion of the first member, thus solving cracking or corrosion problems of a conventional welding process and also welding an over-lay clad metal with leads, thereby generating economic benefits and increasing the convenience of the welding process.

Abstract: A mode-locked laser (MLL) that produces ultra-low phase noise optical and RF outputs, includes two nested resonant optical cavities including an optical fiber-based cavity and an etalon, and a three bandwidth Pound-Drever-Hall (PDH) frequency stabilizer assembly incorporating three different optical bandpass filters. The optical fiber-based cavity is characterized by a free spectral range, FSRfiber, and the etalon is characterized by a free spectral range, FSRfilter, wherein FSRfilter/FSRfiber is an integer equal to or greater than 2. A method of generating ultra-low phase noise optical and RF outputs is disclosed. Optical and RF outputs have a phase noise that is less than ?100 dBc/Hz at 1 Hz and less than ?150 dBc at 10 KHz.

Abstract: The present invention relates to a light source device and a measuring device which use a change in mode-locked resonated output light over time using a change in a cycle of an electrical signal corresponding to a change in the intensity of the output light according to a mode locking condition for each of different light paths in a resonator. The light source device includes an electrical signal generator configured to control the intensity of an optical signal from the light source device, and an optical gain unit controlled by periodic electrical signals having cycles calculated by dividing a round-trip time of photons corresponding to each of different light paths by an integer multiple. The intensity of the optical signal is controlled by the optical gain unit.

Abstract: Methods, systems and apparatus are disclosed for delivery of pulsed treatment radiation by employing a pump radiation source generating picosecond pulses at a first wavelength, and a frequency-shifting resonator having a lasing medium and resonant cavity configured to receive the picosecond pulses from the pump source at the first wavelength and to emit radiation at a second wavelength in response thereto, wherein the resonant cavity of the frequency-shifting resonator has a round trip time shorter than the duration of the picosecond pulses generated by the pump radiation source. Methods, systems and apparatus are also disclosed for providing beam uniformity and a sub-harmonic resonator.

Abstract: A configuration is provided which includes: a reference light source to emit laser light; an optical phase modulator to perform phase modulation of transmission light of the laser light on the basis of a linear-phase-modulation signal having a first frequency component and a second frequency component; an optical intensity modulator to modulate light intensity of the transmission light on the basis of a pulsed light generation signal for generation of pulsed light; first and second optical antennas to emit the transmission light to a space and receive reflected light from a first point and a second point; an optical receiver to perform heterodyne detection on light obtained by mixing received light and local oscillation light; and a signal processor to separate a received signal on the basis of the first and the second frequency components.

Abstract: An optical receiver and communication method receives an optical signal by an optical resonator to provide an intensity modulated signal indicative of a modulation of the optical signal. The intensity modulated signal is provided to a channel receiver of a plurality of channel receivers, and the channel receiver recovers from the intensity modulated signal a multipath version of a transmitted signal embedded in the modulation of the optical signal. The channel receiver's output is combined with an output of at least one other of the plurality of channel receivers to provide a combined output signal.

Abstract: The present disclosure provides methods and apparatus to improve the dynamic coherent length of a sweep velocity-locked laser pulse generator (SV-LLPG) in an all-electronic fashion. A digital SV-LLPG is disclosed with two operation modes, i.e., unidirectional and bidirectional sweep modes; self-adaptive and time-dependent loop parameters (gain and location of poles/zeros); and, self-adaptive initial input curve. High frequency locking architectures, both single-side band (SSB) modulation method and direct phase measurement method, are provided to suppress the linewidth, or improve the coherent length, of the swept laser. A combination of high and low frequency locking, or a combination of multiple architectures disclosed in this invention, is utilized to achieve a higher level of linewidth reduction.

Abstract: A pulsed fiber generator is configured with a unidirectional ring waveguide configured to emit a train of pulses. The ring waveguide includes multiple fiber amplifiers, chirping fiber components coupled to respective outputs of first and second fiber amplifiers, and multiple spectral filters coupled to respective outputs of the chirping components. The filters have respective spectral band passes centered around different central wavelengths so as to provide leakage of light along the ring cavity in response to nonlinear processes induced in the ring cavity. The pulse generator operates at a preliminary stage during which it is configured to develop a pitch to a signal, and at a steady stage during which it is configured to output a train of pulses through an output coupler at most once per a single round trip of the signal.

Abstract: A passive mode-locked laser method and system, the system comprising a nonlinear optical loop comprising a resonant nonlinear element, coupled to an amplification section by a beam splitter, the beam splitter splitting a light beam from the amplification section into light beams propagating in opposite directions around the nonlinear optical loop, the resonant nonlinear element acting as both a nonlinear element and a narrow bandwidth filter for the laser system, allowing mode-locking operation of the system on a single resonance of the resonant nonlinear element.

Abstract: An FM LIDAR system is described that includes a frequency modulated LIDAR system that incorporates a laser source that is optically coupled to a whispering gallery mode optical resonator. Light from the laser that is coupled into the whispering gallery mode optical resonator is coupled back out as a returning counterpropagating wave having a frequency characteristic of a whispering gallery mode of the optical resonator. This returning wave is used to reduce the linewidth of the source laser by optical injection. Modulation of the optical properties of the whispering gallery mode optical resonator results in modulation of the frequency of the frequencies supported by whispering gallery modes of the resonator, and provides a method for producing highly linear and reproducible optical chirps that are highly suited for use in a LIDAR system. Methods of using such an FM LIDAR system and vehicle assisting systems that incorporate such FM LIDAR systems are also described.

Abstract: A method for operating a laser device (1), wherein an optical frequency comb can be stabilized and the frequencies of the modes thereof are describable by the formula fm=m×frep+f0, where frep is a mode spacing, f0 is an offset frequency and m is a natural number. At least one signal (S1, S2, S3, S4) is determined, which correlates with an actual value of a degree of freedom (F), wherein the degree of freedom (F) is a linear combination of the offset frequency f0 and the mode spacing frep of the frequency comb. The actual value of the degree of freedom (F) is set in a predetermined capture range (F) of a second control unit (40) using a first control unit (10) on the basis of the signal. As soon as the capture range (?Fcapture) of the second control unit (40) is reached, the second control unit (40) is activated and the actual value is regulated to an intended value (?Fintended) with the aid of the second control unit (40).

Abstract: Optical fiber amplifiers are disclosed that utilize optic fibers encapsulated by graphene as the gain medium. Doped fiber optic amplifiers utilize optic fibers that are doped with a rare earth element for the gain medium that is encapsulated by graphene. Raman fiber optic amplifiers utilize an undoped fiber as the gain medium that is encapsulated by graphene.

Abstract: A large-scale tunable-coupling ring array includes an input waveguide coupled to multiple ring resonators, each of which has a distinct resonant wavelength. The collective effect of these multiple ring resonators is to impart a distinct time delay to a distinct wavelength component (or frequency component) in an input signal, thereby carrying out quantum scrambling of the input signal. The scrambled signal is received by a receiver also using a large-scale tunable-coupling ring array. This receiver-end ring resonator array recovers the input signal by imparting a compensatory time delay to each wavelength component. Each ring resonator can be coupled to the input waveguide via a corresponding Mach Zehnder interferometer (MZI). The MZI includes a phase shifter on at least one of its arms to increase the tunability of the ring array.

Abstract: According to the present invention, a measurement device includes an electromagnetic wave detector, a phase measurement unit and a deriving unit. The electromagnetic wave detector detects an electromagnetic wave having a frequency equal to or more than 0.02 THz and equal to or less than 12 THz having traveled inside an object to be measured, which is an aggregation of particles. The phase measurement unit measures a change in phase of the electromagnetic wave generated by the travel inside the object to be measured based on a detection result by the electromagnetic wave detector. The deriving unit derives hardness or porosity of the object to be measured based on a measurement result by the phase measurement unit.

Abstract: A method for correcting frequency offset in a dual comb spectroscopy system is provided. The method includes causing a first laser (L1) generator to transmit L1 pulses at a repetition rate of a first frequency and causing a second laser (L2) generator to transmit L2 pulses at a repetition rate of a second frequency. The method also includes interrogating a reference material using a combination of the L1 pulses and the L2 pulses and capturing reference cell pulses. The method further includes interrogating a material of interest using the L1 pulses and capturing material of interest pulses. The method includes determining a frequency jitter based on the captured reference cell pulses and the combination of the captured material of interest pulses and the L2 pulses.

Abstract: A frequency tuneable laser device includes a cavity mode selector and a cavity tuning arrangement. The cavity mode selector has a frequency response with a selection feature that is alignable in frequency with a selected cavity mode of the laser device. The cavity tuning arrangement includes a plurality of reflective elements arranged in optical series, and is used to adjust the effective optical path length of the laser cavity to move the cavity modes in frequency. The laser device further includes making the cavity mode selector and the cavity tuning arrangement perform a simultaneous coordinated movement such that respective frequencies of the selection feature and the selected cavity mode vary with substantially the same dependence on a parameter characterizing the simultaneous coordinated movement. For example, a periscope with a co-rotating etalon can be used to provide mode hop free tuning of the laser device.

Abstract: The locking of optical carriers to a grid can be achieved by employing an optical filter that exhibits athermal behavior in a frequency range to lock at least the frequency of a first channel to a target frequency. The locked frequency may be used to tune and lock the location of the free spectral range of a bandpass filter having transmission peaks at intervals, e.g., an FSR, corresponding to the target grid. The bandpass filter is used generate feedback signals that are used to lock the remaining frequencies to the grid. The athermal filter may be integrated on a silicon photonic integrated circuit.

Abstract: Systems and methods for tuning multi-input complex dynamic systems in order to automatically obtain optimal performance are provided. Training is performed by measuring performance of the complex system using an objective function for a sparse sampling of input values over a variety of dynamic regimes. A sparse representation of the performance for each dynamic regime is stored in a library. At run-time, performance is measured and matched to a sparse representation in the library, and the complex system is configured with the optimal input values associated with the matching sparse representation from the library. Performance may then be optimized using an extremum-seeking controller. In some embodiments, the disclosed techniques are applied to a self-tuning mode-locked laser. In some embodiments, the disclosed techniques are applied to other complex systems such as phased array antennas and neurostimulation systems.

Abstract: A system and method for cooling electric machines using direct winding heat exchangers (DWHX) is disclosed. The system can comprise a plurality of DWHXs disposed in thermal communication with a plurality of copper windings in the stator of an electric machine for cooling the plurality of copper windings. The plurality of DWHXs can also be in fluid communication with one or more fluid manifolds for providing coolant to the plurality of DWHXs. The one or more manifolds can be in fluid communication with one or more heat reservoirs for rejecting the heat absorbed by the plurality of DWHXs. The heat reservoir can be an internal system radiator or an infinite reservoir such as a cooling pond. The method can comprise a design tool for optimizing a DWHX cooling system utilizing the internal system radiator or an infinite reservoir, among other things.

Abstract: The invention describes a laser device (100) enabling controlled emission of individual laser beams (194). The laser device (100) comprises an optically pumped extended cavity laser with one gain element whereby a multitude of pump lasers (110) are provided in order to generate independent pump beams (191) and thus corresponding laser beams (194). The laser device (100) may be used to enable simplified or improved laser systems (500) as, for example, two or three-dimensional laser printers. The pump laser (110) may be VCSEL and the laser (160) may be a VECSEL monolithically integrated with the pump VCSEL array on the same substrate. Pump mirrors (140) and external cavity mirror (150) may be integrated into a single optical reflector with regions having different curvature. The laser emission is controlled by the pump light, i.e. transversal shape of the laser beam and/or number of laser beams is controlled by switching on/off the individual pump lasers (110).

Abstract: A method and a system for measuring an optical asynchronous sample signal. The system for measuring an optical asynchronous sampling signal comprises a pulsed optical source capable of emitting two optical pulse sequences with different repetition frequencies, a signal optical path, a reference optical path, and a detection device. Since the optical asynchronous sampling signal can be measured by merely using one pulsed optical source, the complexity and cost of the system are reduced. A multi-frequency optical comb system using the pulsed optical source and a method for implementing the multi-frequency optical comb are further disclosed.

Abstract: A mode-locked laser has optical components integrated into a single apparatus and interrelated via optical free-space coupling. The laser optical cavity path is reduced to less than ten meters, primarily composed of optical gain fiber. A Fabry-Perot filter is matched to the laser pulse repetition frequency. Utilizing a Fabry-Perot filter within the laser optical cavity suppresses supermode spurs in the phase noise spectrum; thereby reducing total timing jitter.