Abstract: A description is given of an optical structure (100), in particular for determining and stabilizing the relative phase of short pulses, which contains a broadening device (6) for broadening the frequency spectrum of pulses of electromagnetic radiation, and a frequency multiplier device (8) for multiplying at least one frequency component of the pulses, wherein a focusing lens optic (7) is arranged between the broadening device and the frequency multiplier device, which focusing lens optic can be used to focus the pulses into the frequency multiplier device (8). Uses of this optical structure are also described.

Abstract: Disclosed are an apparatus and a method for controlling phases of beams to make relative phases of the beams “O” in a beam splitting amplification laser using a stimulated Brillouin scattering phase conjugate mirror. A procedure of making a phase difference between laser beams reflected from the phrase conjugate miror “O” comprises a first step of inputting laser beams 104?, . . . , 114? and 124? reflected from the phrase conjugate mirrors to a light detector 150 through light path converters 131 and 132; a second step of using one of the reflected laser beams as a reference laser beam 104? and making the reference laser beam intefere with another reflected laser beam 114?; and a third step of detecting the interference result and finely driving piezoelectric elements 109 and 119 to control the positions of the reflectors 108, 118 and 128, to thereby make a phase difference between the laser beam 104? and 104? become “O”.

Abstract: A method (and system) of coherently combining a plurality of diodes in an external cavity laser diode system includes adjusting the phase of the plurality of diodes to correct phase errors, wherein the adjusting the phase includes intercavity phase adjustment. The laser diode external cavity system includes an adjuster for intercavity phase adjustment.

Abstract: A fiber Chirped Pulse Amplification (CPA) laser system includes a fiber mode-locking oscillator for generating a laser for projecting to a fiber stretcher for stretching a pulse width of the laser wherein the stretcher further comprising a self-phase modulation (SPM) assisted photonics crystal fiber (PCF) single mode (SM) fiber stretcher. The fiber CPA laser system further includes a multistage amplifier for amplifying the laser and a high-order dispersion-compensating compressor for compensating high order dispersions and compressing the pulse width of the laser.

Abstract: Two thin-clad laser diodes are disposed to form a stack-type diode laser device. The diodes emit two beams that are substantially parallel and in proximity such that they share many fiberoptic systems designed for a single beam. The diodes are coupled by leaky waves through top surfaces. The leaky waves are generated by a thin metal contact layer or diffractive gratings. The stack-type device is employed for single-mode power enhancement and tunable lasers.

Abstract: This invention relates to opto-electronic systems using semiconductor lasers driven by feedback control circuits that control the laser's optical phase and frequency. Feedback control provides a means for coherent phased laser array operation and reduced phase noise. Systems and methods to coherently combine a multiplicity of lasers driven to provide high power coherent outputs with tailored spectral and wavefront characteristics are disclosed. Systems of improving the phase noise characteristics of one or more semiconductor lasers are further disclosed.

Abstract: An apparatus and method for high speed phase modulation of optical beam with reduced optical loss. In one embodiment, an apparatus includes a first region of an optical waveguide disposed in semiconductor material. The first region has a first conductivity type. The apparatus also includes a second region of the optical waveguide disposed in the semiconductor material. The second region has a second conductivity type opposite to the first conductivity type. A first contact is included in the apparatus and is coupled to the optical waveguide at a first location in the first region outside an optical path of an optical beam to be directed through the optical waveguide. The apparatus also includes a first higher doped region included in the first region and coupled to the first contact at the first location to improve an electrical coupling between the first contact and the optical waveguide. The first higher doped region has a higher doping concentration than a doping concentration within the optical path.

Abstract: A solid state zig-zag slab laser amplifier in which depolarization occurring at total internal reflection from opposed lateral faces of the amplifier slab is controlled by selecting a complex evanescent coating that provides a selected phase retardance that results in minimization of depolarization. Without use of the complex coating, small changes in incidence angles can result in phase retardance changes large enough to increase depolarization significantly, especially when the amplifier is operated at higher powers. Appropriate selection of the complex evanescent coating allows a desired phase retardance angle to be maintained relatively constant over a small range of angles of incidence, at a given wavelength, and therefore permits minimization of depolarization and birefringence effects.

Abstract: The invention features an apparatus and an associated method for illuminating a target area. The apparatus includes reflectors defining a first optical cavity. The first optical cavity defines a first set of longitudinal modes. The apparatus includes a first gain medium defining a first gain band. The first gain medium is configured to cause a plurality of the longitudinal modes of the first set to oscillate over an oscillation band within the first gain band when the first gain medium is pumped at an operative level. The apparatus includes a first optical waveguide positioned within the first optical cavity. The first optical waveguide has a length selected to cause a temporal coherence length of light emitted from the first optical cavity to be shorter than a scattering distance associated with the target area.

Abstract: An optical lasing device, comprising (i) a lasing medium disposed in a lasing cavity, (ii) an etalon disposed within the lasing cavity, and (iii) an electrically tuned filter device, such as a grating waveguide structure device. The lasing device also comprises a detector for determining the lasing power of the lasing device, and a controllable phase shift capability, and the device is preferably locked to a maximum of the lasing power by adjusting the phase, thereby achieving locking to a wavelength predetermined by the etalon, aligned to an ITU grid wavelength. Adjusting the phase shift to achieve the maximum of the lasing power is preferably performed using a closed loop system. Furthermore, adjusting of the phase shift to achieve a maximum of the lasing power is preferably also operative to wave lock the lasing device to a peak wavelength of the etalon.

Abstract: Wavelength control and stabilization of a laser is achieved by a practical, inexpensive, and accurate technique adapted for most optical transmission system applications by a method involving a laser characterization phase and a laser wavelength control and stabilization phase. This technique is applicable to both single mode lasers and multimode lasers. It is especially useful in those applications where the desired laser output power can vary over a wide range, including relatively low power above the lasing threshold.

Abstract: According to each embodiment of the present invention, a phase-correlation can be generated between respective laser fields produced by a plurality of independent lasers. Specifically, based on a structure that first and second laser fields each having a mixed quantum state represented by a single-mode Glauber coherent state that a phase is completely indeterminate are mixed with each other and a quantum continuous measurement is performed by causing absorbers to individually cross two output quantum states, the phase-correlation can be generated between the first and second laser fields when absorption by the absorbers massively occurs in one of the two quantum states as a result of the quantum continuous measurement.

Abstract: An apparatus and method generating an optical pulse of picosecond class (having a high duty ratio), which accurately and stably operates at an arbitrary repetition frequency, has a high OSNR, and is not restricted by an RF modulation frequency, are provided. New modulation spectrum components are generated by performing phase modulation for light output from a single wavelength laser light source with an optical phase modulator. The phases of the modulation spectrum components are aligned by a phase adjuster, so that a pulse wave in a time domain is generated.

Abstract: A driving method of a semiconductor laser having an active layer region, a phase adjustment region and a distributed Bragg reflector region includes the steps of: calculating an average value of multipulse modulation currents modulated between a peak current and a bottom current input to said active layer region; calculating a difference between the average value of the multipulse modulation currents and a bias current input to the active layer region; and applying a first compensation current to the phase adjustment region when the multipulse modulation current is input to the active layer region, and applying a second compensation current corresponding to the difference to the phase adjustment region when the bias current is input to the active layer region.

Abstract: A laser optical apparatus which removes speckles from a screen by changing the phase of a laser beam so as to form an image having high visibility. The laser optical apparatus includes an incident unit on which a laser beam is incident; a multichannel connector having at least two channels having different distances of a route of the laser beam incident on the incident unit so that channels emit beams having different phases; and an exit unit from which the laser beam having a phase changed by the multichannel connector is emitted.

Abstract: A coherent laser beam combining system wherein the output of a single master oscillator is split into a plurality of N signals, and the N signals are electronically modulated at unique frequencies. There is no reference signal and all of the signals are passed through phase adjusters. All N signals are optically amplified, aligned and passed through a beam splitter to split off a small sample that is imaged onto a photodetector. The photodetector output is fed to a signal processor that separates the N signals and produces N phase error signals that drive the N phase adjusters resulting in a high-powered optically coherent output signal.

Abstract: The present invention contemplates a method and apparatus to generate a laser probe beam free of speckles. The present invention employs a holographic phase plate inserted in a laser beam path to modulate the relative phase across the beam. The holographic phase plate is designed to optimize the phase modulation across the beam while to minimize the degradation of the beam quality. The modulated laser beam has only a small and confined divergent angle and can then be refocused or collimated into a narrow and near collimated probe beam. The present invention further rotates the holographic phase plate to randomize the speckles in a time sequence. As a result, the probe beam preserves substantially the beam quality of a laser and produces substantially no speckles on image of its, intersection with a surface or material.

Abstract: A hybrid laser source including a solid state laser driven by an array of fiber laser amplifiers, the inputs of which are controllable in phase and polarization, to compensate for distortions that arise in the solid state laser, or to achieve desired output beam properties relating to direction or focus. The output beam is sampled and compared with a reference beam to obtain phase and polarization difference signals across the output beam cross section, at spatial positions corresponding with the positions of the fiber laser amplifiers providing input to the solid state laser. Therefore, phase and polarization properties of the output beam may be independently controlled by predistortion of these properties in the fiber laser amplifier inputs.

Abstract: The invention relates to a laser resonator for semiconductor lasers having a waveguiding layer which is disposed between a substrate and a superstrate, the waveguiding layer, the substrate and/or the superstrate of the laser resonator having at least one phase structure which varies locally in such a manner that at least one predetermined laser mode is influenced in its propagation characteristic.

Abstract: According to each embodiment of the present invention, a phase-correlation can be generated between respective laser fields produced by a plurality of independent lasers. Specifically, based on a structure that first and second laser fields each having a mixed quantum state represented by a single-mode Glauber coherent state that a phase is completely indeterminate are mixed with each other and a quantum continuous measurement is performed by causing absorbers to individually cross two output quantum states, the phase-correlation can be generated between the first and second laser fields when absorption by the absorbers massively occurs in one of the two quantum states as a result of the quantum continuous measurement.

Abstract: To provide a semiconductor laser device that is capable of outputting high power laser light and is suitable for optical recording, optical communication, welding, and the like, and a multiple wavelength laser light emitting apparatus employing the semiconductor laser device. The semiconductor laser device includes an optical element that at least partially reflects a laser beam emitted from an end face of a laser light oscillator in a semiconductor laser array element so that the laser beam is incident on another laser light oscillator. Due to this, even when laser light oscillators are disposed with such a pitch that does not pose problems in manufacturing, a laser beam emitted from an end face of one laser light oscillator and a laser beam emitted from an end face of another laser light oscillator are phase-locked. By condensing these laser beams, the semiconductor laser device can output higher power laser light than conventional.

Abstract: Speckle of a laser beam is reduced by inserting an anti-speckle apparatus in the beam path to disrupt its spatial coherence while maintaining its temporal coherence. In one embodiment, the anti-speckle apparatus is a phase retarder plate bearing periodic optically-coated regions. Transmission or reflection of the beam through coated and uncoated regions causes an internal phase shift of first beam portions relative to second beam portions, thereby disrupting spatial coherence. Size and thickness of the coated regions can be carefully tailored to meet requirements of stepper and scanner equipment manufacturers for maximum allowable spatial coherence expressed as a minimum permissible number of coherent cells across the beam cross-section. An alternative embodiment of an anti-speckle apparatus is a scattering plate bearing a roughened surface. Transmission or reflection of the beam by the roughened surface disrupts the beam's spatial coherence.

Abstract: There is provided a phase control portion for controlling phase of a laser beam resonated in a resonator based on detected results by two optical detectors. The phase control portion adjusts the longitudinal mode positions by a feedback control so that a ratio of intensities detected by the two optical detectors comes to a predetermined reference value. To one of the optical detectors, part of a laser beam outputted from the resonator is irradiated as it is, whereas, to the other one of the optical detectors, part of the laser beam outputted from the resonator is irradiated after passing through an etalon. An FSR of the etalon is a double of that of another etalon in the resonator.

Abstract: One embodiment of the present invention includes an optical cavity, a source to provide light to the optical cavity, a sensor to detect the light and generate a corresponding sensor signal, and a servo device including a feedforward input and a feedback input. Feedback from the sensor signal is provided to the servo device to regulate operation of the source at a frequency selected to generate an optical field resonating in the first mode in the cavity. An input device provides a control signal to a control input of the servo device that selectively alters operation of the light source to corresponding halt resonance in the first mode. An evaluation device is also included to evaluate decay of the optical field after resonance in the first mode is halted.

Abstract: A discontinuous phase element (86, 204) is disposed between the reflector (20, 23) elements of an optical resonator in order to suppress unwanted modes propagating within the cavity, and to preferentially allow the existence of preferred modes within the cavity. The discontinuous phase element (204) operates by producing sharp changes in the phase distribution of the undesirable modes, so that their propagation losses are sufficiently high prevent their build-up. This is achieved by introducing a discontinuous phase change to these modes at locations where they have high intensity. At the same time, the desired modes suffer 0 or 2&pgr; phase change, or have low intensity at the discontinuity, and so are unaffected by the discontinuous phase element. Such elements can be used in a single element or a double element configuration, and can be used in passive cavities or active cavities, such as lasers.

Abstract: A Laser arrangement (1) comprising a pump unit (2) containing a pumped laser crystal (3), and means, such as a saturable absorber (15), for passive mode-locking, wherein two separate, alternatively switchable resonator arms (11, 12) are provided, one resonator arm (11) of which, which is active in a pulse forming phase (21), comprises the saturable absorber (15), whereas the other resonator arm (12), which is active in an amplifying phase (22), is free from components that introduce losses.

Abstract: A laser includes a first region with a first moveguide having a first diffraction grating, a second region with a second waveguide having a second diffraction grating, and a phase controlling region with a third waveguide and a phase control unit for controlling an effective refractive index of the third waveguide. The phase controlling region, the first region and the second region are coupled serially along a light propagation direction in this order, and are constructed such that light to the first region from the phase controlling region is enlarged relatively to light to the phase controlling region from the first region, or constructed such that a coupling coefficient of the first diffraction grating in the first region adjacent to the phase controlling region is smaller than a coupling coefficient of the second diffraction grating in the second region away from the phase controlling region.

Abstract: The invention concerns an ultrahigh frequency emitting device, having: at least a first and a second microlaser (22, 24), emitting at two different frequencies &ohgr;1 and &ohgr;2, means of slaving the first and the second microlaser frequency-wise, an array of N elements (N≧2) (52, 54, 56, 58) placed on the path of the beam of the second laser, each element making it possible to impose a phase delay on the beam which passes through it, N means (26, 28, 30, 32) for mixing the beam emitted by the first laser and each of the N delayed beams, and for producing N signals of frequency &ohgr;1-&ohgr;2, N antenna-forming means (34, 36, 38, 40) for emitting radiation at the frequency &ohgr;1-&ohgr;2.

Abstract: A method of generating light pulses in an ultrawide band ranging from the near-infrared region to the near-ultraviolet region. Fundamental sub-picosecond pulses emitted from an ultrashort pulse laser (1) are passed through a nonlinear optical material (6) to produce wavelength-converted pulses whose center wavelength differs from that of the fundamental pulses. The method comprises the steps of separating the converted pulses from the fundamental pulses, delaying the converted pulses relative to the fundamental pulses, adjusting the polarization of the converted or fundamental pulses, adjusting the energy of the fundamental and converted pulses, superposing the separated fundamental and converted pulses on each other, and allowing the superimposed pulses to pass through a nonlinear optical material (22).

Abstract: The invention relates to an improved method and system for synchronizing signals in a particle accelerator system. In one embodiment, a method and system is disclosed whereby a phase of laser pulses are monitored, and a high-frequency signal is adjusted as necessary to be substantially in-phase with the laser pulses. In another embodiment, a method and system is disclosed whereby a phase of an electromagnetic field in an electron gun is monitored, and a high-frequency signal is adjusted as necessary to be substantially in-phase with the electromagnetic field.

Abstract: A system and method for reducing peak power of a laser pulse and reducing speckle contrast of a single pulse comprises a plurality of beamsplitters, mirrors and delay elements oriented to split and delay a pulse or pulses transmitted from a light emitting device. The design provides the ability to readily divide the pulse into multiple pulses by delaying the components relative to one another. Reduction of speckle contrast entails using the same or similar components to the power reduction design, reoriented to orient received energy such that the angles between the optical paths are altered such that the split or divided light energy components strike the target at different angles or different positions. An alternate embodiment for reducing speckle contrast is disclosed wherein a single pulse is passed in an angular orientation through a grating to create a delayed portion of the pulse relative to the leading edge of the pulse.

Abstract: Optical chirped return-to-zero (CRZ) data signals are generated without the need for a separate phase modulator, by using a dual-drive Mach-Zehnder modulator for RZ pulse carving that is driven with two typically sinusoidal signals of either unequal amplitude or unequal relative phase, i.e. of non-vanishing phase difference.

Abstract: In a method and apparatus for synchronizing the output of two passively modelocked pulsed lasers, the output of each laser is sampled and delivered to two photodiodes, one for each laser. The output of the each photodiode is converted to a train of digital pulses having the pulse repetition frequency of each laser. The digital pulses are processed in a digital phase detector that generates from the digital pulses a first analog voltage representative of the phase difference at the photodiodes between corresponding pulses in each train. This analog voltage is summed with a second analog voltage representative of a desired phase relationship of the laser pulses at a target location remote from the photodiodes. The sum of the analog voltages provides an error signal that commands a device to adjust the length of the resonator of one of the lasers. When the error signal is minimized, pulses from each laser have the same repetition frequency and have the desired phase relationship at the target.

Abstract: An apparatus including a cavity optical length actuator to vary a cavity optical path length of a laser in response to an excitation signal having varying frequencies. The cavity optical length actuator induces intensity perturbations in an optical beam of the laser corresponding to the excitation signal. A sensor senses the intensity perturbations in the optical beam and generates a response signal corresponding to the intensity perturbations. A combiner combines the excitation signal and the response signal to generate an error signal.

Abstract: A method for selecting free spectral ranges (FSR) of intra-cavity optics to optimize reliability of the channel switching mechanism and corresponding apparatus. In particular, the optimal relationship between the FSR of the internal etalon and the FSR of the laser cavity is derived. For the external cavity diode lasers (ECDL) the optimal relationship between the FSR of the internal etalon and the FSR of the gain chip is also derived. Equations are derived for selecting free spectral ranges of various optical cavities so as to create a locally commensurate condition under which the relative position of the lasing mode with respect to the transmission peak of the laser's tunable filter (e.g., etalon plus channel selector) does not change when the laser hops between adjacent channels.

Abstract: A method of wavelength locking and mode monitoring a tuneable laser that includes two or more tuneable sections in which injected current can be varied, including at least one reflector section and one phase section. Laser operation points are determined as different current combinations through the different laser sections, and the laser operates at a predetermined operation point. The wavelength of light emitted by the laser is detected by a wavelength selective filter. The laser is controlled in an iterative process in which alternated currents through the reflector section and, when applicable, its coupler section, and the current through the phase section are adjusted. The currents through the reflector section and the coupler section are adjusted to obtain a minimum ratio between power rearwards and power forwards. The current through the phase section is adjusted to hold the wavelength constant, the wavelength being measured against a wavelength reference.

Abstract: A method and apparatus for accurately and precisely controlling the frequency (wavelength) and periodic frequency modulation of a laser are provided. An ADC (Analog to Digital Converter) is used to sample the output of a modified interferometer used as a delay line discriminator, and quadrature components of the sampled output are generated. An arctangent function (e.g., atan2) is applied to convert the quadrature components to a phase measure that is proportional to the laser frequency. Correlator circuits (e.g., cost-efficient correlator circuits) are provided to extract average frequency, modulation peak deviation, and modulation phase error signals. Control-loop feedback using the extracted signals is used to adjust the average frequency, modulation deviation, and modulation phase to respective set points.

Abstract: Microwaves are generated by heterodyning the outputs of two or more optical lasers which have differing central frequencies to produce beat frequencies in the microwave range. One of the beat frequencies is used to modulate the output of at least one of the lasers so as to produce sidebands which differ from the central frequency by an integral number of the sideband frequency. Each laser is connected to one of the other lasers by a weak optical link to optically injection lock the laser to the sideband of the other laser.

Abstract: A mirror system for use in generating a short duration laser pulse is disclosed. The system includes first and second double-chirped mirrors disposed along an optical path within a cavity, where the second double-chirped mirror includes an additional phase-shifting layer as compared to the first double-chirped mirror. The additional phase-shifting layer causes the mirror system during use to produce a laser pulse that is characterized by oscillations in group delay substantially reduced in amplitude in comparison to oscillations in group delay for a pulse produced by the same system without the additional phase-shifting layer.

Abstract: Apparatus for stabilizing an output wavelength of a laser assembly (80), including a plurality of optical elements (88, 92, 97, 96) coupled together so as to form a laser cavity resonating in a single mode dependent upon an optical length of the cavity, and an optical length changer (86) which varies an optical length of at least one of the optical elements so as to vary accordingly the optical length of the cavity. The apparatus further includes a detector (91) which monitors the output of the laser assembly responsive to the variation in the optical length of the at least one of the optical elements. There is also included a stabilizer (93) which responsive to the measured output from the detector supplies a control signal to the optical length changer to control an optical length of at least one of the optical elements, so that the cavity resonates stably at the output wavelength in the single mode.

Abstract: A real-time wavelength calibration scheme for a swept laser generates an electrical signal from a swept optical output of the swept laser that is cyclical with respect to the wavelength of the swept optical output over a defined range of wavelengths. The point on the electrical signal at any given time provides an accurate phase for the swept optical output at that point. The electrical signal in turn is calibrated by generating calibration references from the swept optical output using known absorption lines within the defined range of interest. The wavelength of the swept laser is calibrated as a function of a reference wavelength from the known absorption lines and the phase at the given point.

Abstract: Improved frequency stabilizing equipment for a light source for optical communication is provided. Light from the light source is selected by a light switch. An external modulator is used to perform amplitude modulation of modulated light selected by the switch. The modulated light passed through a dispersion generator having a wavelength-dependency characteristic is mixed with a local oscillating light signal outputted from a photoelectric converter. The mixed light is converted photoelectrically by a light receiver having a non-linearity characteristic between an input light signal and output electrical signal. By using photoelectriclly converted electrical signal, a difference in phase between the light signal inputted into the dispersion generator and the output light signal of the dispersion generator and the wavelength of the modulated light outputted from the light source is controlled so that the phase difference is a predetermined reference value.

Abstract: An electro-optical system includes a plurality of electromagnetic gain media having a corresponding plurality of apertures. The apertures are disposed in a predetermined spatial distribution. The system further includes a refracting surface disposed to intercept energy from the plurality of apertures and a partially reflecting surface to direct portions of the intercepted energy back toward the plurality of apertures with the directed energy being distributed about the plurality of apertures.

Abstract: The invention relates to a method and a circuit arrangement for a laser control loop with automatic adaptation to the monitoring signal polarity. Use is made of a single-phase method which consists in that a signal produced by the monitor during the starting phase of the laser control loop is compared with a reference value, and in accordance with the result of the comparison the signal produced by the monitor is fed directly or inverted to the comparator for controlling the light power of the laser during the starting phase of the laser control loop. A signal is produced which initially feeds the comparator for controlling the light power the inverted monitoring signal, or directly feeds the monitoring signal, in a fashion always independent of the monitoring signal polarity, but dependent on the polarity of a reference value, and feeds it in a non-inverted fashion in the case of a monitoring signal running up to the reference value.

Abstract: The WDM light source comprises a light source which generates an optical signal for an optical channel. The optical signal is intensity modulated with modulating signals. The modulated optical signal is applied to a dispersion generating circuit, at which dispersion occurs on the optical signal, according to the wavelength of the signal. A phase difference detector detects phase difference between the optical signal input to the dispersion generating circuit and the optical signal output from the dispersion generating circuit. According to the detected phase difference, the control signal which corresponds to delay time is generated. The control signal is fed back to the light source thus the wavelength of the light source is controlled.

Abstract: A laser with microwave excitation includes a source of microwave radiation coupled to a microwave resonator. The resonator is configured such that the microwave radiation generates an oscillating electric-field perpendicular to the longitudinal axis of the resonator corresponding to the first longitudinal resonator mode standing wave pattern. An excitation cavity, housing at least one gas discharge conduit, is coupled to the microwave resonator along a major portion of the cavity's length. The excitation cavity is configured to be below cutoff.

Abstract: To provide a semiconductor laser device that is capable of outputting high power laser light and is suitable for optical recording, optical communication, welding, and the like, and a multiple wavelength laser light emitting apparatus employing the semiconductor laser device. The semiconductor laser device includes an optical element that at least partially reflects a laser beam emitted from an end face of a laser light oscillator in a semiconductor laser array element so that the laser beam is incident on another laser light oscillator. Due to this, even when laser light oscillators are disposed with such a pitch that does not pose problems in manufacturing, a laser beam emitted from an end face of one laser light oscillator and a laser beam emitted from an end face of another laser light oscillator are phase-locked. By condensing these laser beams, the semiconductor laser device can output higher power laser light than conventional.