Abstract: Dry oxygen, dry air, or other gases such as ozone are hermetically sealed within the package of the external cavity laser or ASE swept source to avoid packaging-induced failure or PIF. PIF due to hydrocarbon breakdown at optical interfaces with high power densities is believed to occur at the SLED and/or SOA facets as well as the tunable Fabry-Perot reflector/filter elements and/or output fiber. Because the laser is an external cavity tunable laser and the configuration of the ASE swept sources, the power output can be low while the internal power at surfaces can be high leading to PIF at output powers much lower than the 50 mW.

Abstract: Apparatus and method for control of lasers (which use an array of optical gain fibers) in order to improve spectrally beam-combined (SBC) laser beam quality along the plane of the SBC fiber array via spectral-to-spatial mapping of a portion of the spectrally beam-combined laser beams, detection of optical power in each of the spatially dispersed beams and feedback control of the lasers for wavelength-drift correction. The apparatus includes a diffractive element; a source of a plurality of substantially monochromatic light beams directed from different angles to a single location on the diffractive element, wherein the diffractive element spectrally combines the plurality of light beams into a single beam. A controller adjusts characteristics of the light beams if one of the light beams has become misadjusted. In some embodiments, the controller adjusts the wavelength tuning of the respective fiber laser.

Abstract: The present invention is a laser irradiation apparatus which is capable of selecting among a plurality of laser lights L having different wavelengths a laser light of a wavelength according to a purpose of irradiation and irradiating an object Ob to be irradiated with the laser light having the wavelength. The laser irradiation apparatus includes: on an optical path of a mixed light beam of the plurality of laser lights L having different wavelengths, a slit having a width corresponding to a diffraction limit of the laser light having the shortest wavelength among the plurality of laser lights L having different wavelengths; and an objective lens for focusing a laser light that has passed through the slit, on the object Ob to be irradiated.

Abstract: A laser system includes an array of lasers that emit light at a number of different, fixed wavelengths. A group of optical transport systems connect to the laser system. Each of the optical transport systems is configured to modulate data signals onto the light from the laser system to create optical signals and transmit the optical signals on one or more optical fibers.

Abstract: A projection apparatus includes at least one laser diode and a laser diode junction temperature estimator to estimate the junction temperature of the at least one laser diode. Laser diode current drive values are modified in response to the estimated laser junction temperature. The modification of laser diode current drive values may occur as frequently as once per pixel.

Abstract: Embodiments of the invention provide a laser light source comprising: a plurality of lasers connected in series; and a laser driver controllable to simultaneously drive a substantially same current through a combination of the lasers selectable from different combinations of lasers in the plurality of lasers and not through lasers in the plurality of lasers that are not in the combination.

Abstract: An ultrashort pulse/ultra-high power laser diode with a simple structure and configuration is provided. In a method of driving a laser diode, the laser diode is driven by a pulse current which is 10 or more times higher than a threshold current value. The width of the pulse current is preferably 10 nanoseconds or less, and the value of the pulse current is specifically 0.4 amperes or over.

Abstract: A disclosed multi-beam laser power control circuit includes a light receiving element receiving power output from semiconductor lasers to control output power of a semiconductor laser array having plural semiconductor lasers, automatic power control circuits (APC circuits) controlling emission power output from semiconductor lasers based on received corresponding automatic power control execution signals so as to be set to predetermined emission power based on output from the light receiving element, and APC execution signal input terminals inputting the corresponding automatic power control execution signals, wherein, when plural APC execution signals input to the corresponding APC execution signal input terminals are overlapped, the automatic power control circuits (APC circuits) to be preferentially operated is determined based on input timings of the APC execution signals and operated.

Abstract: A semiconductor laser driving device and an image forming apparatus are disclosed that are capable of accurately detecting the deterioration of the semiconductor laser with a smaller circuit size and regardless of the variation of the characteristics of the semiconductor laser and the use conditions of the semiconductor laser by adding a minimum circuit are disclosed. In the semiconductor laser driving device, the output voltage generated by an operational amplifier circuit by amplifying a voltage difference between a monitoring voltage (Vm) and a predetermined reference voltage (Vref) is transmitted to a bias current generating circuit unit as a bias current setting voltage (Vbi) through a sample/hold circuit having a switch (SW1) and a sample/hold capacitor (Csh). When the bias current setting voltage (Vbi) is greater than a predetermined voltage, a deterioration detecting circuit transmits a deterioration detecting signal indicating that the deterioration of the semiconductor laser is detected.

Abstract: A light source device includes: a light source section which comprises plural laser diodes; a pulse driving section which divides the laser diodes of the light source section into plural groups, each group having the same number of the laser diodes, and drives the laser diodes of the each group by a pulse having a predetermined period and a predetermined duty ratio; and a light source driving section which controls a phase of the pulse for the each group so that the same number of the laser diodes are emitted in succession when the laser diodes of the each group are driven by the pulse driving section.

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

Abstract: Apparatus and method for control of lasers (which use an array of optical gain fibers) in order to improve spectrally beam-combined (SBC) laser beam quality along the plane of the SBC fiber array via spectral-to-spatial mapping of a portion of the spectrally beam-combined laser beams, detection of optical power in each of the spatially dispersed beams and feedback control of the lasers for wavelength-drift correction. The apparatus includes a diffractive element; a source of a plurality of substantially monochromatic light beams directed from different angles to a single location on the diffractive element, wherein the diffractive element spectrally combines the plurality of light beams into a single beam. A controller adjusts characteristics of the light beams if one of the light beams has become misadjusted. In some embodiments, the controller adjusts the wavelength tuning of the respective fiber laser.

Abstract: In one embodiment, a transmitter can bias a vertical-cavity surface-emitting laser (VCSEL) coupled to an optical medium. The biasing of the VCSEL determines at least in part an optical power output by the VCSEL to the optical medium. The transmitter can also modulate the VCSEL with data to transmit the data optically through the optical medium to a receiver; receive from the receiver through a feedback channel an error vector representing a degradation in performance of the VCSEL sensed by the receiver or an instruction vector comprising one or more coefficients for use in biasing the VCSEL; and adjust the biasing of the VCSEL based on the error vector or the instruction vector to regulate the optical power output by the VCSEL to the optical medium.

Abstract: A system and methods for the quasi-remote compression and focusing of a moderate-intensity laser pulse to form a much higher intensity beam that can be directed at a target and used as a probe beam or used in a probe beam converter to generate other forms of electromagnetic radiation or energetic particles. A system for the quasi-remote propagation of high-intensity laser beams in accordance with the present invention comprises a main platform on which a first, “seed” laser pulse is generated, stretched, and amplified, and a remote platform, located at a distance from the main platform, which is configured to receive the amplified and stretched pulse and convert it into the high-intensity laser beam. The high-intensity laser beam in turn can then be converted into one or more probe beams directed at a target object.

Abstract: Disclosed are systems and methods for improving wavelength control in tunable laser sources. Embodiments of the systems and methods include delivering a fraction of the light output from the laser to an optical filter subsystem. The optical filter subsystem is capable of outputting at least one filter response signal, and comprises 2 complementary optical etalon filters with nominally identical free spectral ranges but offset by nominally one third of the free spectral range. The filter response signal is processed in a control unit which executes a control algorithm to generate a tuning signal that is used to control the wavelength of the laser.

Abstract: A pulse width modulation method for controlling the output power of a pulsed gas discharge laser powered by a pulsed RF power supply comprises delivering a train of digital pulses to the RF power supply. Each pulse in the train has an incrementally variable duration. The power supply is arranged to deliver a train of RF pulses corresponding in number and duration to the train of digital pulses received. The average power in the RF-pulse train can be varied by incrementally varying the duration of one or more of the digital pulses in the digital pulse train. The train of RF pulses is used to power a gas discharge laser. The gas discharge laser outputs a pulse train corresponding to the RF pulse train.

Abstract: The present invention provides a method of driving a semiconductor laser, where the method can control changes in the internal temperature of a device as well as control optical output using a driving current. A method of driving a semiconductor laser includes steps of: preliminary driving the semiconductor laser by preliminary activating at a current value larger than a threshold value; de-activating the semiconductor laser, after the step of preliminary driving; and starting a formation of a latent image on a photosensitive drum based on a latent image formation signal, after the step of de-activating.

Abstract: A method to control an LD (laser diode) is disclosed. The method compares the operating temperature of the LD with a transition temperature. When the former temperature exceeds the latter, the modulation current is set based on the bias current, which is independently determined by the APC loop. On the other hand, the operating temperature is less than the transition temperature; the modulation current is determined by the operating temperature.

Abstract: A projector with a laser light source projects an image. In order to reduce the risk for a person to be exposed to harmful levels of laser light, the projector also projects a time-variant alerting image into an alerting region. Alerting region is arranged outside of the projection region. The alerting image is of a wave length visible to the human eye, and of an intensity of eye-safe level.

Abstract: The invention concerns an optical pointing device comprising a coherent light source for illuminating a surface portion with radiation, a driver of the coherent light source for controlling coherent light emissions, a photodetector device responsive to radiation reflected from the illuminated surface portion, processing means for determining, based on the photodetector device response, a measurement of relative motion between the optical pointing device and the illuminated portion of the surface, wherein the coherent light source driver is a fault-tolerant driver comprising redundant power control means for limiting the output power of coherent light emissions.

Abstract: A Dynamically Variable Spot Size (DVSS) laser system for bonding metal components includes an elongated housing containing a light entry aperture coupled to a laser beam transmission cable and a light exit aperture. A plurality of lenses contained within the housing focus a laser beam from the light entry aperture through the light exit aperture. The lenses may be dynamically adjusted to vary the spot size of the laser. A plurality of interoperable safety devices, including a manually depressible interlock switch, an internal proximity sensor, a remotely operated potentiometer, a remotely activated toggle and a power supply interlock, prevent activation of the laser and DVSS laser system if each safety device does not provide a closed circuit. The remotely operated potentiometer also provides continuous variability in laser energy output.

Abstract: The present invention relates to an atomic frequency acquisition device comprising a gas cell (400) filled with an atomic gas, a laser light source (100) emitting a laser beam which enters the gas cell (40) and excites a first energy transition of the atomic gas, a local oscillator (700) for generating an oscillator frequency in a frequency range including a frequency of a HFS transition of the atomic gas, and a modulator (600) modulating the laser light source (100) so as to emit laser radiation modulated with the oscillator frequency. An optical reflector (500) is arranged behind the gas cell (400) to reflect the laser beam after passage through the atomic gas so as to re-enter the laser cavity. A photodetector (200) detects beat frequencies caused by self-mixing interference within the laser cavity.

Abstract: A laser gain medium includes an optical medium configured to transmit a laser beam and having an incident face, a first face, a second face opposing to the first face; and gain media configured to amplify the laser beam while reflecting the laser beam. At least one of the gain media is joined on a first face of the optical medium as a first face gain medium, and at least one of the remaining gain media is joined on a second face of the optical medium as a second face gain medium. The laser beam is incident into the optical medium, and is amplified by the first face gain medium and the second face gain medium while being alternately reflected by the first face gain medium and the second face gain medium.

Abstract: A closed loop system for controlling laser temperature without the need for additional sensors or other hardware. Embodiments utilize an existing automatic power feedback loop and existing sensors to determine the temperature of a TOSA based on changes in laser bias current, thus avoiding the need for the additional hardware. The automatic power feedback loop will modify the laser bias current as the temperature of the TOSA changes. That is, as the temperature increases, the amount of laser bias current is increased and as the temperature decreases, the amount of laser bias current is decreased. Thus, the laser bias current may be used as feedback for the laser temperature control. Accordingly, when the transceiver module drops below a predetermined temperature, a laser heater current may be controlled to thereby maintain the same laser bias current as at the preset temperature.

Abstract: The present invention relates to a laser processing apparatus and the like having a structure for implementing at the same time both an efficient laser processing in the place where a laser beam is difficult to reach and a laser processing without damages in the place where the laser beam is easy to reach. This laser processing apparatus comprises a laser light source, an irradiation optical system applying a laser beam to an object while scanning the laser beam, a photo-detector detecting the laser beam applied from the irradiation optical system, and a control section of making switching between a continuous oscillation and a pulse oscillation of the laser beam at the laser light source.

Abstract: Output pulses from an optical system having a seed source and an optical amplifier coupled to the seed source may be controlled by controlling a power of a seed signal from the seed source. The seed signal may be varied between a minimum value and a maximum value in a way that the seed signal exhibits one or more pulse bursts. Each pulse burst may contain one or more pulses. During an inter-pulse period between successive pulses within a pulse burst or between successive pulse bursts, the power of the seed signal may be adjusted to an intermediate value that is greater than the minimum value and less than the maximum value. The intermediate value is chosen to control a gain in the optical amplifier such that a pulse or pulse burst that follows the period exhibits a desired behavior.

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

Abstract: A fiber laser processing apparatus controls a LD drive current ILD in a power feedback control mode (FIG. 3E) such that output of a fiber laser beam FB rises substantially from zero or a value around zero to a preceding level having no substantial effect on laser processing and arrives at a desired level (PA) for the laser processing from a preceding level PB after a first time period (preceding pulse width TB) has elapsed (time point t2 of FIGS. 3A to 3F) from the start of the rising to the preceding level (time point t1 of FIGS. 3A to 3F), and this may effectively prevent occurrence of a high-peak pulse HP at the rising edge of the fiber laser beam FB (FIG. 3F).

Abstract: An ultrashort pulse/ultra-high power laser diode with a simple structure and configuration. The laser diode can be driven by a pulse current which is 10 or more times higher than a threshold current value. The width of the pulse current is preferably 10 nanoseconds or less, and the value of the pulse current is specifically 0.4 amperes or over.

Abstract: A device for determining the position of a structure (3) on an object (2) in relation to a coordinate system is disclosed. The object (2) is placed on a measuring table (20) which is movable in one plane (25a), wherein a block (25) defines the plane (25a). At least one optical arrangement (40, 50) is provided for transmitted light illumination and/or reflected light illumination. The optical arrangement (40, 50) comprises an illumination apparatus (41, 51) for reflected light illumination and/or transmitted light illumination and at least one first or second optical element (9a, 9b), wherein at least part of the at least one optical element (9a, 9b) extends into the space (110) between the block (25) and an optical system support (100). The block (25) and/or the optical system support (100) separates the illumination apparatus (41, 51) spatially from the plane (25a) in which the measuring table (20) is movable.

Abstract: An ultrashort pulse/ultra-high power laser diode with a simple structure and configuration is provided. In a method of driving a laser diode, the laser diode is driven by a pulse current which is 10 or more times higher than a threshold current value. The width of the pulse current is preferably 10 nanoseconds or less, and the value of the pulse current is specifically 0.4 amperes or over.

Abstract: A method and apparatus are disclosed for controlling bandwidth in a multi-portion laser system comprising a first line narrowed oscillator laser system portion providing a line narrowed seed pulse to an amplifier laser system portion, may comprise utilizing a timing difference curve defining a relationship between a first laser system operating parameter other than bandwidth and the timing difference and also a desired point on the curve defining a desired timing difference, wherein each unique operating point on the curve corresponds to a respective bandwidth value; determining an actual offset from the timing difference at the desired point on the curve to an actual operating point on the curve; determining an error between the actual offset and a desired offset corresponding to a desired bandwidth; modifying the firing differential timing to remove the error between the actual offset and the desired offset.

Abstract: An optical device includes: a light source including a plurality of light emitting spots that output laser beams, respectively; a separating unit that separates each of the laser beams output from the plurality of light emitting spots into a monitor beam and a scanning beam; a light-quantity measuring unit that measures a light quantity of the monitor beam; a storage unit in which respective drive currents with which the plurality of light emitting spots of the light source output a prescribed light quantity of laser beams are stored in advance; a light-source control unit that drives the light source with the drive currents stored in the storage unit and causes the plurality of light emitting spots to output the laser beams; and a determining unit that determines whether the light source operates properly on the basis of the light quantity measured by the light-quantity measuring unit.

Abstract: Techniques are disclosed that enable fine features such as serifs and narrow strokes of texts to be produced by xerographic devices, for example. The fine features may be generated by subpixels which are produced when a pulse width used to image a pixel is shorter than a corresponding physical size of a laser beam spot used to write the image on a Xerographic photoreceptor. The laser driver may be modified to drive a light emitting element with a boost current profile that includes an overshoot above a steady state current at a rising edge. The overshoot results in a light intensity time profile that has an increased area for a subpixel.

Abstract: The invention relates to a method for the adjustment of the beam axis of a laser head and an apparatus for this purpose. The method includes the steps of introducing the laser head (3) into a mounting (8), determining the set/actual deviation of the beam axis (2), determining of motions (6A and/or 6B) necessary for reduction of the deviation, and adjustment of the beam axis (2) by driving the adjusting device (4) to generate the adjusting motions (6A and/or 6B), and transmitting the adjusting motions (6A and/or 6B) via the both arms (7A, 7B) of the adjusting lever (7) to the laser head (3) which is arranged in the mounting (8).

Abstract: A digital pulse shaping module for controlling a pulsed laser oscillator according to a digital input waveform is provided. The pulse shaping module includes a clock generator generating a plurality of phase-related clock signals and a shape generator which outputs a digital shape signal corresponding to the digital input waveform in Double Data Rate in response to the clock signals. A DAC converts the digital shape into an analog shape signal. The analog shape signal may be used to control the current source of a laser seed source or modulators in the laser oscillator shaping a seed light signal. Optionally, the pulse shaping module may also output a gate control signal having a predetermined timing relationship with respect to the digital shape signal.

Abstract: A laser gain medium includes an optical medium configured to transmit a laser beam and having an incident face, a first face, a second face opposing to the first face; and gain media configured to amplify the laser beam while reflecting the laser beam. At least one of the gain media is joined on a first face of the optical medium as a first face gain medium, and at least one of the remaining gain media is joined on a second face of the optical medium as a second face gain medium. The laser beam is incident into the optical medium, and is amplified by the first face gain medium and the second face gain medium while being alternately reflected by the first face gain medium and the second face gain medium.

Abstract: Disclosed in a laser projector to display an image by projecting a laser beam from a laser light source to a projection screen including an electromagnetic driven scan mirror to scan the laser beam from the laser light source, a detection unit to detect a back EMF which is generated by a drive of the electromagnetic driven scan mirror at a time of start-up of the laser projector, a first determination unit to determine whether a value of the back EMF which is detected by the detection unit exceeded a predetermined threshold or not and a light source control unit to start a lighting of the laser light source when the value of the back EMF is determined as exceeding the predetermined threshold by the determination unit.

Abstract: A semiconductor laser using an external resonator. A laser diode chip emits a laser beam in a horizontal direction parallel to the bottom plane of a package, and the travel path of the laser beam is changed into a vertical direction by a reflective mirror next to a laser beam-emitting surface of the laser diode chip. As a result, the beam arrangement of the external cavity is available on a plane parallel to the bottom plane of the package through a lens installed on the vertical travel path of the laser beam. Consequently, the beam is easily arranged. Further pore, an additional reflective mirror is installed above the lens which changes the vertical travel path into a horizontal travel path, which allows the beam traveling parallel to the bottom plane to be easily arranged through the lens. The production of the package can also be enabled in the configuration where various optical tools are arranged on the bottom of the package.

Abstract: This invention relates to opto-electronic systems using semiconductor lasers driven by optical phase-locked loops that control the laser's optical phase and frequency. Feedback control provides a means for precise control of optical frequency and phase, including the ability for broadband electronic tunability of optical signals and the cascading of multiple lasers for enhanced tunability and coherent combining for increased output power.

Abstract: A cut-out portion of a ground conductor is located in a region where a header faces a flexible board from the junction of a signal pin and a signal line and faces the signal line. The size of the cut-out portion is determined so that the impedance of the signal pin is matched to the impedance of the signal line.

Abstract: A system and method for uniform light generation in projection display systems. An illumination source comprises a light source to produce colored light, and a scrolling optics unit optically coupled to the light source, the scrolling optics unit configured to create lines of colored light from the colored light, and to scroll the lines of colored light along a direction orthogonal to a light path of the illumination source. The scrolling optics unit comprises a single light shaping diffuser to transform the colored light into the lines of colored light, an optical filter positioned in the light path after the light shaping diffuser, and a scrolling optics element positioned in the light path after the optical filter. The single light shaping diffuser is capable of simultaneously transforming colored light into lines of colored light having substantially uniform intensity to provide uniform illumination.

Abstract: A projection type display apparatus is provided that is safe even when a person looks directly into a laser beam. A laser operation control unit sets the output power of at least one laser source so that intensity A (mW/mm2) of the laser beam on at least one spatial light modulation element satisfies relationship of A<686×B2 when numerical aperture B on image side of an illumination optics system is set.

Abstract: A method for monitoring laser light launched into a core of a single mode fiber includes launching a portion of light directly into the cladding about the core. The cladding launched light is a known fraction of the core launched light and can be monitored by placing a detector about the cladding. Detected light including light that was launched into the cladding and has leaked through the cladding is used as a known fraction of light in the core and can be used to control the laser light source. This can be done with a straight section of single mode optical fiber and does not require bending the fiber. Advantageously, most of the core launched light remains in the core as guided light.

Abstract: A method of protecting a laser against damage caused by undesired incident light in a resonator includes measuring a parameter, which is a measure for the optical power of the incident light. In more concrete terms, the optical power occurring at a resonator mirror is measured. In response to a result of the measurement, a pumping power for the laser is reduced to reduce the optical power in the resonator to a value that is uncritical for the laser.

Abstract: The present invention provides a control device capable of performing feedback control so that a signal-wavelength input to a control target object becomes a specific signal-wavelength, using an input signal whose duty value is other than 50%. Accordingly, the control device according to the present invention is a control device for performing feedback control so that a signal-wavelength input to a control target object (500) becomes a specific signal-wavelength, the control device including a control unit (100) that performs feedback control so that the signal-wavelength input to the control target object (500) becomes the specific signal-wavelength, using an input signal input to the control target object (500), the input signal whose duty value is other than 50%.

Abstract: A method for aligning an optical package includes applying a dither waveform and an advancement waveform to a drive mechanism. The optical package includes a semiconductor laser operable to emit an output beam with a first wavelength, a wavelength conversion device operable to convert the output beam to a second wavelength, adaptive optics configured to optically couple the output beam into a waveguide portion of an input facet of the wavelength conversion device, and a drive mechanism coupled to the adaptive optics and configured to adjust a position of the output beam. The dither waveform oscillates the adaptive optics back and forth in first and second directions to oscillate the output beam on the input facet. The advancement waveform advances the adaptive optics in an adjustment direction. Rising and falling edge times of the dither waveform are greater than rising and falling edge times of the advancement waveform.

Abstract: Techniques for measuring optical modulation amplitude (OMA) are disclosed. For example, a technique for measuring an OMA value associated with an input signal includes the following steps/operations. The input signal is applied to a photodetector, wherein the photodetector is calibrated to have a given responsivity value R, and further wherein the photodetector generates an output signal in response to the input signal. The output signal from the photodetector is applied to a radio frequency (RF) power meter, wherein the RF power meter measures the root mean squared (RMS) power value of the output signal received from the photodetector. The OMA value associated with the input signal is determined in response to the root mean squared (RMS) power value measured by the RF power meter. The OMA value may be determined as a function of a factor F derived from a relationship between an amplitude of a data signal and the RMS value of the data signal.

Abstract: A gas discharge laser includes a laser housing including a laser gas and an electrode-assembly for lighting a discharge in the laser gas. The electrode assembly has a first resonant frequency when the discharge is not lit and a second resonant frequency when the discharge is lit. RF power delivering circuitry of the laser includes an arrangement for determining and recording the two resonant frequencies. RF power is applied to the electrodes at the first recorded resonant frequency to facilitate lighting of the discharge, and thereafter at the second resonant frequency to light and sustain the discharge.

Abstract: A tunable optical local oscillator is used for optical heterodyne signal detection using an electrooptic Mach-Zehnder modulator to produce a rapidly tunable optical signal from a tunable RF frequency generator. A combination of the Mach-Zehnder modulator and optical fibers for providing stimulated Brillouin scattering are used to suppress unwanted signals for providing a spectrally pure optical local oscillator waveform. Suppression of unwanted optical signals, up to 50 dB, generated by the Mach-Zehnder modulator is obtained, resulting in high spectral purity of the optical local oscillator waveform with an extended tuning range of the tunable optical oscillator equal to the operating bandwidth of up to 60 GHz of the Mach-Zehnder modulators.