Abstract: A process and device are provided for stabilizing the emission wavelength of an optical source, which emits radiation at a first wavelength, by locking to the emission wavelength of an optical reference source which emits radiation at a second wavelength which is substantially different from the first. The stabilization device applies to the source to be stabilized a feedback signal obtained by detection of an optical beat between the two radiations. A two-photon absorption for the first wavelength is used to generate the beat.

Abstract: A laser radiation source is provided with an array of N individual slave laser diodes in a predetermined surface area. Adjustable power supply networks enable adjustment of the slave laser diodes relative to one another for operation in a stable manner. The slave power supply has a separate power supply network for each slave laser diode. Each of the power supply networks can be adjusted with respect to the current supplied to the respective slave laser diode during a certain operating period. This enables adjusting the slave laser diodes relative to one another. The power supply networks can be connected in parallel and supplied by a common source.

Abstract: The invention relates to an optical modulation device for coupling an entering radiation field (12), with which an incident radiation field (40) is divided into a transmitted branch (40T) and a diffracted branch (40B) by means of a first acousto-optical modulation and a diffracted and a transmitted branch are respectively generated by means of a second acousto-optical modulation so that the transmitted branch (40BUT) resulting from the deflected diffracted branch (40BU) and the diffracted branch (40TUB) resulting from the deflected transmitted branch (40TU) propagate in approximately the same direction and form a first radiation field (46) as a result of essentially constructive interference and, in addition, the transmitted branch (40TUT) resulting from the deflected transmitted branch (40TU) and the diffracted branch (40BUB) resulting from the deflected diffracted branch (40BU) propagate in the same direction and form a second radiation field (48) as a result of essentially destructive interference.

Abstract: A method is provided for managing test measurements for an optical entity. The method can include determining if testing is needed, and building an object that includes a test variable and a plurality of independent variables. If testing is needed, the method can include measuring a test variable value, and revising the object to include the test variable value.

Abstract: The effective coherence of an undulator beamline can be tailored to projection lithography requirements by using a simple single moving element and a simple stationary low-cost spherical mirror. The invention is particularly suited for use in an illuminator device for an optical image processing system requiring partially coherent illumination. The illuminator includes: (i) source of coherent or partially coherent radiation which has an intrinsic coherence that is higher than the desired coherence; (ii) a reflective surface that receives incident radiation from said source; (iii) means for moving the reflective surface through a desired range of angles in two dimensions wherein the rate of the motion is fast relative to integration time of said image processing system; and (iv) a condenser optic that re-images the moving reflective surface to the entrance plane of said image processing system, thereby, making the illumination spot in said entrance plane essentially stationary.

Abstract: The invention relates to compound cavity optical reflection modulation laser system providing frequency modulation of laser light by phase induced effective reflection modulation of the laser rear facet. The system includes a single mode gain coupled DFB laser integrated with a passive waveguide section to form a compound cavity modulation system. The waveguide includes a multiple quantum well region which is reverse biased to utilize the quantum Stark effect for voltage controlled refractive index modulation, thus providing phase modulation of the laser light. The phase modulated light is fed back to the laser to interfere with the light generated within the laser and to form the output light generated from the compound cavity. The interference effects cause modulation of the effective complex reflection of the rear laser facet which results in frequency modulation of the output light.

Abstract: In an optical transmission apparatus including an external optical modulator for modulating an optical carrier from a light source with an electrical signal, bias voltage applied to the external optical modulator is accurately adapted to fluctuations in optimal bias voltage due to DC drift. A bias voltage control circuit controls bias voltage applied by a bias voltage applier to an external optical modulator so as to minimize an amount of second order distortion included in an optical signal from the external optical modulator and caused by non-linearity thereof.

Abstract: A modulation control system is used in fiber optic data transmission and fiber optic test equipment. A modulation controller includes a plurality of function generators that are linked by a switching mechanics, to a rail system that drives a plurality of laser source cards, The switching mechanism for each rail is capable of driving the rail at the function-generated waveform or switching to an external source waveform. The laser source cards are intelligent in the sense that they can be programmably controlled by switching to select waveforms from a selected one of the rails.

Abstract: An optical fiber cascaded Raman laser scheme is provided. An optical fiber cascaded Raman laser scheme in accordance with an embodiment of the present invention includes a pump light source, an optical fiber, a wavelength division multiplexing optical fiber combiner, another wavelength division multiplexing optical fiber combiner, a short period optical fiber bragg grating, a long period bragg grating, first means, and second means. The pump light source generates pump light. The optical fiber causes Raman scattering regarding the optical pump light as nonlinear material. The wavelength division multiplexing optical fiber combiner forms intra cavity regarding light of second order stoke frequency shifted wavelength. The light is stoke frequency shifted by Raman scattering of the optical fiber. The another wavelength division multiplexing optical fiber combiner forms intra cavity regarding light of first and third order stoke frequency shifted wavelength.

Abstract: A frequency-converted laser apparatus includes an optical pumping source that produces fundamental laser radiation and an external resonant cavity having one beam path direction-marked frequency conversion crystal within said resonant cavity or just beam path direction-marked frequency conversion crystals without an additional resonant cavity. The “to-be-used” direction of said frequency conversion crystal is well defined or clearly marked. The frequency converted laser radiation after said frequency conversion crystal shows better beam quality and much higher power stability if said frequency conversion crystal is used in the “to-be-used” direction.

Abstract: At least part of the waveguide of a laser, the waveguide including a first cladding layer, an active layer, and a second cladding layer of a second conductivity type, and, for a ridge type laser, a ridge in the second cladding layer, has a width such that light leaks from the side walls of the waveguide. A case encloses the side walls of the waveguide and a fluid having a refractive index is sealed in the case in contact with the side walls of the waveguide. A characteristic of the laser can be adjusted easily. Therefore a laser having a uniform characteristic can be provided at a low cost. This laser is useful as a light source for wavelength multiplex transmission used for optical transmission, of a main line system, such as a submarine cable.

Abstract: A wavelength-selectable laser system (10) is achieved by addressing the suitable mode-locked frequency of a multi-length laser cavity formed by multiple wavelength-selective mirrors (20) such as fiber gratings. This is useful for fiber optic communication and WDM (wavelength division multiplexing) networks where there is incorporated an information encoder/modulator (22) of the light in the sending side and a detector in the receiving side, which are matched to the laser system.

Abstract: A laser oscillation device, which has an optical fiber where laser ion is doped; an excitation emission element that generates one laser beam including multiple wavelength components by exciting the laser ion in the optical fiber by light emission; a total reflection element that is located at one end of the optical fiber and reflects uniformly laser beam with multiple wavelengths; a separation optical element that is located at another end of the optical fiber and separates laser beam into beams with multiple wavelengths; and a plurality of partial reflection element that reflect separately laser beams with multiple wavelengths separated by the separation optical element.

Abstract: A laser diode pumped solid state laser includes a solid laser medium, and an index optical waveguide type laser diode which emits a pumping light beam for pumping the laser medium. A high-frequency which is higher than a response frequency of the solid laser medium and is of an amplitude which makes a percentage modulation of the light output of the laser diode a value not smaller than 50% and smaller than 100% is superposed on a drive current for the laser diode.

Abstract: Ellipsometer having a light source (L1, L2) which during operation provides a first light beam (g1) having a first angular frequency (&ohgr;1) and a second light beam (g2) having a second angular frequency (&ohgr;2), a neutral beam splitter N having a front face for receiving and at least partially transmitting a measurement beam (g′m2), which, during operation, is produced by scanning a sample (S; OD1, OD2) with the second light beam (g2), and a rear face for receiving the first light beam (g1). During operation, the measurement beam (g′m2) interferes with the first light beam (g1) at the rear face and an interference beam is thus formed. A unit (W1) receives the interference beam, separating the orthogonal components of the interference beam and providing two alternating voltages (V1, V2) corresponding thereto. The light source comprises a first laser source (L1) for only producing the first light beam (g1) and a separate laser source (L2) for only producing the second light beam (g2).

Abstract: An apparatus and a method for laser frequency stabilization include a laser, a modulator, a derivative module, a Fabry-Perot etalon, a photodetector, a balanced mixer, a signal processing module, and a feedback control module. The laser has an output and lases at a single frequency. The laser has a desired frequency and provides an optical signal including a substantial frequency chirp signal. The modulator is coupled to the laser and provides a modulation signal for modulating the laser. The derivative module is coupled to the modulator and provides a derivative signal which is a time derivative of the modulation signal. The Fabry-Perot etalon is coupled to the output of the laser and has a frequency response including a plurality of resonances. One of the plurality of resonances is centered on the desired frequency. The etalon filters the optical signal according to the frequency response.

Abstract: A semiconductor tunable laser system includes a tunable Fabry-Perot cavity and a cavity length modulator, which controls an optical length of the cavity at least over a distance corresponding to the spacings between the longitudinal modes of the laser cavity. Thus, the tunable Fabry-Perot cavity allows the laser cavity to have gain at the desired wavelength of operation while the cavity length modulator tunes the cavity length such that a longitudinal cavity mode exists at the desired wavelength of operation. Also, in one embodiment, a wavelength locker system is further provides that has a differential wavelength filter, e.g., stepped etalon, and a multi-element detector, e.g., a quad-detector. The controller then modulators the Fabry-Perot cavity to control the wavelength in response to the signal received from the multi-element detector.

Abstract: The frequency standard comprises a quantum absorber, source of incident electr-omagnetic radiation, detector, controller and signal output. The quantum absorber has a transition between a lower quantum state split by hyperfine interaction into two lower sub-state groups of at least one lower sub-state, and an upper quantum split by hyperfine interaction into upper sub-state groups of at least one upper sub-state. None of the upper sub-state groups is a cycling transition sub-state group having at least one allowed electric dipole transition to one lower sub-state group but none to the other. The upper quantum state differs in energy from a first lower sub-state in one of the lower sub-state groups and from a second lower sub-state in the other of the lower sub-state groups by energy differences that correspond to frequencies of &ohgr;1 and &ohgr;2, respectively.

Abstract: A laser system is disclosed wherein a tunable laser signal has encoded within it information related to its wavelength at any instant in time. This encoding in one example is performed by modulating the signal to contain its wavelength information. This is particularly useful in a distributed system for testing optical components, wherein at a test site, the test station must determine the wavelength of light at which a component was tested.

Abstract: A tunable semiconductor laser system includes a laser with a semiconductor active region positioned between upper and lower confining regions of opposite type semiconductor material. First and second reflective members are positioned at opposing edges of the active and confining regions. A wavelength tuning member and a temperature sensor are coupled to the laser. A control loop is coupled to the temperature sensor and the tuning member. In response to a detected change in temperature the control loop sends an adjustment signal to the tuning member and the tuning member adjusts a voltage or current supplied to the laser to provide a controlled output beam of selected wavelength.

Abstract: A semiconductor tunable laser system includes a tunable Fabry-Perot cavity and a cavity length modulator, which controls an optical length of the cavity at least over a distance corresponding to the spacings between the longitudinal modes of the laser cavity. Thus, the tunable Fabry-Perot cavity allows the laser cavity to have gain at the desired wavelength of operation while the cavity length modulator tunes the cavity length such that a longitudinal cavity mode exists at the desired wavelength of operation. Also, in one embodiment, a wavelength locker system is further provides that has a differential wavelength filter, e.g., stepped etalon, and a multi-element detector, e.g., a quad-detector. The controller then modulators the Fabry-Perot cavity to control the wavelength in response to the signal received from the multi-element detector.

Abstract: A dynamic change detecting apparatus allows canceling the influence of environmental change or an individual difference between a plurality of laser elements so as to perform a stable detection.

Abstract: A system and method for generating ultrasonic displacements on a remote target. The method of the present invention includes the steps of first using a laser to generate a beam having a first wavelength to produce ultrasonic displacements at the remote target. This laser beam will have a first wavelength which can be modulated to alter characteristics of the ultrasonic displacements. These ultrasonic displacements at the remote target can be optimized to enhance the detection optics for collecting phase modulated light from the second pulsed laser beam either reflected or scattered by the remote target; an interferometer to process the phase modulated light and generate at least one output signal, and means for processing the at least one output signal to obtain data representative of the ultrasonic surface displacements on the surface of the remote target.

Abstract: The invention pertains to a method and to a device for resonance enhancement, in particular for tunable frequency conversion of continuous laser radiation, in particular, with a resonator of mirrors and at least one refractive element. The purpose of the invention is to develop a method and a device of the described type, so that the frequency conversion of continuous laser radiation, in particular, will occur at high efficiency while avoiding the described disadvantages, and so that an improved tunability will be assured over the greatest possible wavelength range with regard to the incident wavelengths; this problem is solved in that a tuning of resonator length is performed by translation of at least one refractive element P. The resonator is formed from a first mirror M1, a second mirror M2, and of a refractive element P designed in trapezoidal shape, which performs the function of a prism.

Abstract: A method is disclosed for frequency stabilization of an optical source, using data obtained from a frequency stabilization system based on an optical frequency discriminator to stabilize the output of a laser to a particular grid channel. The data is mathematically manipulated to double the number of channels as compared to prior art methods and allows arbitrary channel spacing about the channels.

Abstract: The present invention provides a continuously-tunable external cavity laser (ECL) with a compact form factor and precise tuning. A novel interference filter which may be used to tune the ECL provides an absence of mode-hopping and reduced feedback from both spurious interference and reflections in the external cavity. A novel tuning mechanism is disclosed which provides for mechanical FM tuning of a wide range ECL tuning elements such as: an interference filter, a diffraction element, and a retroreflector. A novel feedback circuit is disclosed which provides closed loop feedback for selecting output wavelength in a laser.

Abstract: A wavelength stabilized laser system includes a laser that produces a laser light having an amplitude and a wavelength that varies as a function of a temperature of the laser. A temperature control device controls the temperature of the laser. A beam splitter deflects a portion of the laser light. A first detector receives the portion of the laser light from the beam splitter and provides a first signal representing the amplitude of the laser light. A filter has a gain that is a function of the wavelength of the laser light. The filter receives the laser light and outputs a filtered light having an amplitude that varies with the wavelength of the laser light. A second detector provides a second signal representing the amplitude of the filtered light. A sealed housing contains the laser, the first and second detectors and the filter. The housing has a window.

Abstract: A method for fabricating a Fabry-Perot laser having a cavity length and facet reflectivity product tuned to cause the laser to exhibit a relaxation oscillation frequency of at least 10 GHz, wherein the laser is capable of being modulated at 10 Gb/sec at drive currents between about 20 and 40 mA.

Abstract: A laser beam generating apparatus comprising a first laser beam source oscillating in a near infrared-ray region of, for example, an Nd:YAG laser to generate a laser beam, a second higher harmonic wave generator for generating, from the laser beam emitted from the first laser beam source, a second higher harmonic wave having a half wavelength of the laser beam emitted from the first laser beam source, a splitter for splitting the second higher harmonic wave, a second laser beam source which is supplied with a part of the second higher harmonic wave thus split is input to a Ti:Sapphire laser to be excited and oscillated, thereby generating a laser beam of substantially 700 nm in wavelength, a fourth higher harmonic wave generator for generating a fourth higher harmonic wave from the remaining part of the second higher harmonic wave thus split, a sum frequency mixing composed of a BBO crystal device to which the laser beam of substantially 700 nm in wavelength and the fourth higher harmonic wave are input, and

Abstract: A power supply unit provides therein a first power unit outputting a first excitation amplitude and operating from rising of a reference pulse signal outputted from a reference oscillator until rising of a first time delay signal having a time delay to the reference pulse signal, a second power unit outputting a second excitation amplitude and operating from rising of the first time delay signal until rising of a second time delay signal having a time delay to the first time delay signal, and a third power unit outputting a third excitation amplitude and operating from rising of the second time delay signal until falling of the first time delay signal, and supplies output by synthesizing output from the first power unit, second power unit and the third power unit to the exciting unit.

Abstract: In a single-frequency laser and amplifier system, the radiation of a single-frequency, diode-pumped solid-state laser, preferably of a low power microcrystal laser or a monolithic ring-laser consisting of rare-earth-doped or transition-metal-doped crystal or glass materials, is coupled into a semiconductor amplifier chip (preferably GaAlAs, InGaAs or InGaAsP). The material system and the epitaxial structuring of the amplifier chip are selected to adapt it to the emission wavelength of the solid-state laser, so that it amplifies the single-frequency radiation of the solid-state laser and therefore generates an output beam which is intensified with respect to the coupled-in laser radiation.

Abstract: An optical transmitter (405) includes a distributed feedback semiconductor laser (100) operated in a linear regime below a threshold associated with stimulated Brillouin scattering to generate an optical signal. A resistor (125) or other heater is physically coupled to the semiconductor laser (100), and a modulated current source (120) drives the resistor (125) with a triangle waveform (300), thereby varying an optical wavelength of the optical signal such that the optical signal and a double Rayleigh backscattered signal are characterized, at the optical receiver (410), by different optical frequencies. As a result, interference generated by Rayleigh backscattering is minimized at the optical receiver (410).

Abstract: A system and method for generating a desired acoustic frequency content in a laser-generated ultrasonic wave emitted from a target in response to a laser pulse. The method includes generating a generation laser pulse using a laser source. An optimal wavelength &lgr;0 for the generation laser pulse is determined using a computer. The optimal wavelength data is determined from material-specific, empirically calculated data stored in a storage device that is accessible to the computer. An optimal laser pulse is generated by shifting the generation laser pulse to the optimal wavelength &lgr;0. The optimal laser pulse is directed to the target to generate the laser-generated ultrasonic wave with the desired frequency content.

Abstract: A multi-wavelength Raman radiation source is disclosed. The source receives pump radiation at a given wavelength, e.g., 1100 nm, and has outputs at two or more longer wavelengths, e.g., 1450 nm and 1480 nm. The cascaded Raman resonator comprises, for each desired output wavelength, an optical cavity formed by a high reflectivity grating and a low reflectivity grating, with both having the same center wavelength, equal to the desired output wavelength. Multi-wavelength Raman radiation sources have a variety of applications, e.g., they can advantageously be used in a remotely pumped optical fiber communication system.

Abstract: This invention discloses an optical resonator (24) including at least one spiral optical element (44) operative to change the angular phase distribution of modes in the optical resonator (24), thereby to generally eliminate undesirable modes.

Abstract: In accordance with the present invention, an in-line fiber Bragg grating is coupled to the output of a directly modulated DFB laser. The grating preferably rejects chirp induced frequencies of light emitted by the DFB laser. Accordingly, light transmitted through the grating is spectrally narrowed and has a higher extinction ratio, thereby decreasing bit error rate probabilities.

Abstract: A device and method of track changing an optical signal beam in response to the frequency selective phase characteristics of a resonator. The resonator is side-coupled to a single optical beam and only affects that beam's phase, without disturbing its amplitude to any significant degree. For all resonator and input beam configurations, the phase-shift at a resonant frequency is always .pi., thus the relative switching characteristics are similar regardless of the exact configuration. Track changing is accomplished through interferometry. The signal, after having interacted with the resonator, is made to interfere with a reference beam. The reference beam is created by dividing an input signal into two paths, one which interacts with the resonator, the other which serves as the reference. In an alternative embodiment, the device acts as a mode converter. The resonator converts an even system-mode to an odd system-mode (or vise versa).

Abstract: A current driver circuit for a vertical cavity surface emitting laser (VCSEL), flip-chip bonded to a CMOS device. In a preferred embodiment, the circuit includes only two transistors. Specifically, a P-channel metal-oxide semiconductor (PMOS) source supplies a current under the control of a tuning voltage (Vtune) while an N-channel metal-oxide semiconductor (NMOS) transistor acts as a high-speed current shunt that modulates the current flowing through the VCSEL, and hence its emitted power.

Abstract: VCSEL for high speed operation and method of fabrication including a substrate element, a first stack of distributed Bragg reflectors disposed on a surface of the substrate element, an active region lattice matched to a surface of the first stack of distributed Bragg reflectors, and a second stack of distributed Bragg reflectors lattice matched to a surface of the active region. The active region includes a plurality of quantum well layers, or structures, and a plurality of doped barrier layers. The doping of the barrier layers allows for a faster recombination time of the carriers prior to any occurrence of lateral carrier diffusion. This faster recombination time of the carriers prevents turn-off tails when the VCSEL device is switched off.

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

Abstract: For the generation of amplified, phase-coherent light pulses, a sequence of phase-coherent, equidistant input light pulses (21) is coupled into a resonator device (1) with at least two resonator mirrors (11, 14), forming a light path (10) with a predetermined resonator length, in such a way that the coupled in input light pulses in the resonator device are linearly superimposed in succession to form at least one circulating light pulse, whereby the circulating light pulse is coupled out of the resonator device as an output light pulse (31) as soon as the circulating light pulse has reached a preset minimum level of energy.

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

Abstract: A laser comprises a first contact to receive an active region control signal, a second contact to receive an optical absorber control signal, and a sandwich of distributed Bragg reflector mirror stacks. Each distributed Bragg reflector mirror stack has an alternate doping with respect to an adjacent distributed Bragg reflector mirror stack. An active region is positioned in the sandwich to provide optical gain in response to the active region control signal. An optical absorber is positioned in the sandwich. The optical absorber has wavelength dependent absorption in response to the optical absorber control signal. The device of the invention may be utilized as an integrated detector, a self-pulsating laser, a high speed intracavity modulator, or an optical pick-up device.

Abstract: A technique for characterizing laser chirp utilizes an optical fiber and its inherent interferometric properties. An RF modulating signal is applied to the laser, where the modulated output signal thereafter propagates through a conventional optical fiber. A photoreceiver and spectrum analyzer are coupled to the opposite end of the optical fiber. By adjusting the power of the applied RF signal, the maximum IIN can be determined. The laser chirp can then be calculated by dividing the measurement frequency by the modulation current associated with the maximum IIN value.

Abstract: A method for biasing a semiconductor laser (12) at the threshold level of the semiconductor laser (12). The method includes applying pilot tone signals having the same frequency to a bias current and a drive current of the semiconductor laser (12). A lateral detector (13) generates a photocurrent from spontaneous emissions of the semiconductor laser (12). Further, the method includes biasing the semiconductor laser (12) using a pilot tone signal of the photocurrent.

Abstract: An input signal input to a 180 degree distributor is distributed as two signals, one of which with its phase inverted 180 degrees is input to a first modulation light source and the other with its phase unchanged is input to a second modulation light source; both signals are modulated with the intensity and the frequency of the light emission dependent on signal amplitude. The modulated signals are coupled by an optical coupler and subjected to heterodyne detection through a photodetector, where their light intensity modulation components offset each other when added and the multiplication of their light frequency components results in the frequency transition quantity doubling.

Abstract: A radiation emitting device, such as an LED, is optimally driven in dependence on the value of a carrier frequency of a signal to be transmitted. The current provided to the radiation emitting element is controlled responsive to the carrier frequency. When using an LED, the current value is increased with decreasing duration of current flow. The apparatus is usable for remote controls suitable for controlling two or more devices.

Abstract: A laser array for determining the concentrations of gases. A simply acting device and a corresponding process are provided, which make possible a high signal resolution by reducing the interferences without prolonging the measurement time. The interferences occurring in the laser array are reduced by the laser source being set to perform longitudinal oscillations in the direction of the optical axis. These oscillations preferably have a sinus or sawtooth shape, and a frequency in the range of 10 to 1,000 Hz that does not otherwise occur in the laser array and an oscillation amplitude corresponding to one fourth to a multiple of the wavelength of the radiation of the laser source.

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

Abstract: A laser beam generating device which, by addition of a simplified structure, can enlarge the spectral width of the laser light and lower the coherence to a moderate value. The laser light generating device includes a first laser light source 31, a second laser light source 32, phase modulation units 34, 35 for phase-modulating the beams from the light sources with a sole frequency component or plural frequency components, and an additive frequency generating unit 33 for producing a light beam of the shorter wavelength based on the wavelength of the light phase-modulated by the phase modulation units 34, 30. The fundamental wavelength laser light generated by the first laser light source 31 is phase-modulated by the phase modulation unit 34 based on a pre-set modulation amplitude and the modulation frequency so as to be enlarged in spectral width before being incident on the additive frequency generating unit 33.