Abstract: A laser apparatus according to the present disclosure includes an excitation light source configured to output excitation light, a laser crystal disposed on an optical path of the excitation light, a first monitor device disposed on an optical path of transmitted excitation light after having transmitted through the laser crystal to monitor the transmitted excitation light, a temperature adjustment device configured to adjust a temperature of the excitation light source to a constant temperature based on a temperature command value, and a controller configured to change the temperature command value based on a result of monitoring by the first monitor device.

Abstract: A laser apparatus according to the present disclosure includes an excitation light source configured to output excitation light, a laser crystal disposed on an optical path of the excitation light, a first monitor device disposed on an optical path of transmitted excitation light after having transmitted through the laser crystal to monitor the transmitted excitation light, a temperature adjustment device configured to adjust a temperature of the excitation light source to a constant temperature based on a temperature command value, and a controller configured to change the temperature command value based on a result of monitoring by the first monitor device.

Abstract: A laser apparatus may include: a quantum cascade laser outputting, based on a supplied current, laser light at an oscillation start timing when a first delay time elapses from a current rising timing of the supplied current: an amplifier disposed in a laser light optical path, and selectively amplifying light of a predetermined wavelength to output the amplified laser light to a chamber including a plasma generation region into which a target is fed; and a laser controller controlling a third delay time, from an output timing of a laser output instruction to the current rising timing, to cause a laser light wavelength to be equal to the predetermined wavelength at an aimed timing when a second delay time elapses from the oscillation start timing, based on oscillation parameters including the first delay time, a supplied current waveform, and a device temperature of the quantum cascade laser.

Abstract: A laser apparatus includes a light source configured to output excitation light, an optical resonator in which laser medium is excited by the excitation light, the optical resonator being configured to output laser beam, a temperature regulator configured to adjust temperature of the light source to a standard temperature, an optical detector configured to detect output power of the laser beam, and a controller configured to change the standard temperature based on the detected output power of the laser beam.

Abstract: A laser beam having desired properties is output at desired timings. A laser apparatus is a laser apparatus for use with an extreme ultraviolet light generating apparatus that generates extreme ultraviolet light at a repetition frequency which is set in advance, and may be equipped with: a semiconductor laser that outputs a laser beam when a trigger signal is input thereto; an optical switch that switches between a state in which the laser beam passes therethrough and a state in which the laser beam does not pass therethrough, provided along the optical path of the laser beam; and a control unit configured to output the trigger signal to the semiconductor laser at a frequency which is an integer multiple of the repetition frequency, and to control the optical switch such that the laser beam passes therethrough at the repetition frequency.

Abstract: A laser apparatus includes a light source configured to output excitation light, an optical resonator in which laser medium. is excited by the excitation light, the optical resonator being configured to output laser beam, a temperature regulator configured to adjust temperature of the light source to a standard temperature, an optical detector configured to detect output power of the laser beam, and a controller configured to change the standard temperature based on the detected output power of the laser beam.

Abstract: A laser apparatus may include: a quantum cascade laser outputting, based on a supplied current, laser light at an oscillation start timing when a first delay time elapses from a current rising timing of the supplied current: an amplifier disposed in a laser light optical path, and selectively amplifying light of a predetermined wavelength to output the amplified laser light to a chamber including a plasma generation region into which a target is fed; and a laser controller controlling a third delay time, from an output timing of a laser output instruction to the current rising timing, to cause a laser light wavelength to be equal to the predetermined wavelength at an aimed timing when a second delay time elapses from the oscillation start timing, based on oscillation parameters including the first delay time, a supplied current waveform, and a device temperature of the quantum cascade laser.

Abstract: A laser apparatus may include a beam splitter configured to split a pulse laser beam into a first beam path and a second beam path, an optical sensor provided in the first beam path, an amplifier including an amplification region provided in the second beam path and being configured to amplify and emit the pulse laser beam incident thereon along the second beam path, a wavefront controller provided in the second beam path between the beam splitter and the amplifier, and a processor configured to receive an output signal from the optical sensor and transmit a control signal to the wavefront controller.

Abstract: A laser beam having desired properties is output at desired timings. A laser apparatus is a laser apparatus for use with an extreme ultraviolet light generating apparatus that generates extreme ultraviolet light at a repetition frequency which is set in advance, and may be equipped with: a semiconductor laser that outputs a laser beam when a trigger signal is input thereto; an optical switch that switches between a state in which the laser beam passes therethrough and a state in which the laser beam does not pass therethrough, provided along the optical path of the laser beam; and a control unit configured to output the trigger signal to the semiconductor laser at a frequency which is an integer multiple of the repetition frequency, and to control the optical switch such that the laser beam passes therethrough at the repetition frequency.

Abstract: There is provided a laser unit that may include a master oscillator, a laser amplifier, and an adjuster. The master oscillator may be configured to output a laser light beam. The laser amplifier may be disposed in a light path of the laser light beam outputted from the master oscillator. The adjuster may be disposed in the light path of the laser light beam, and may be configured to adjust a beam cross-sectional shape of the laser light beam amplified by the laser amplifier to be a substantially circular shape. The beam cross-sectional shape may be at a beam waist of the laser light beam or in the vicinity of the beam waist of the laser light beam, and may be in a plane orthogonal to a light path axis.

Abstract: A laser apparatus may include a beam splitter configured to split a pulse laser beam into a first beam path and a second beam path, an optical sensor provided in the first beam path, an amplifier including an amplification region provided in the second beam path and being configured to amplify and emit the pulse laser beam incident thereon along the second beam path, a wavefront controller provided in the second beam path between the beam splitter and the amplifier, and a processor configured to receive an output signal from the optical sensor and transmit a control signal to the wavefront controller.

Abstract: There is provided a laser unit that may include a master oscillator, a laser amplifier, and an adjuster. The master oscillator may be configured to output a laser light beam. The laser amplifier may be disposed in a light path of the laser light beam outputted from the master oscillator. The adjuster may be disposed in the light path of the laser light beam, and may be configured to adjust a beam cross-sectional shape of the laser light beam amplified by the laser amplifier to be a substantially circular shape. The beam cross-sectional shape may be at a beam waist of the laser light beam or in the vicinity of the beam waist of the laser light beam, and may be in a plane orthogonal to a light path axis.

Abstract: An optical clock extraction circuit that can be fabricated at low cost and suppress jitter is achieved. The optical clock extraction circuit extracts an optical clock signal phase-locked to a high-speed optical data signal. The circuit has a saturable absorber mirror, a pulsed light source for producing an optical pulsed signal consisting of repetitive optical pulses, a first optical coupler/splitter for passing the data signal and causing reflected light of the pulsed signal from the mirror to branch off, a second optical coupler/splitter for passing the pulsed signal, causing it to branch off to take out it as the clock signal, and causing reflected light of the data signal from the mirror to branch off, first and second lenses for collecting the data signal and pulsed signal passed through the coupler/splitters at the same position on the mirror and for returning reflected light rays of the two signals from the mirror to the coupler/splitters, respectively, a balanced photodetector, and an oscillator.

Abstract: The object of the invention is to offer a light source device for frequency division multiplexed optical communications having a compact size and reduced cost. Light source units 100-300 output light having optical frequencies which oscillate at mutually different modulation frequencies centered about mutually different optical frequencies. Optical splitters 1-3 split the output light from each light source unit into two parts. An optical multiplexer-splitter 4 multiplexes and splits the output light from the optical splitters. The Fabry-Perot etalon resonator 5 transmits each component of the output light from the optical multiplexer-splitter 4 at a specific transmission rate corresponding to each optical frequency. A light receiving element 6 converts the output light from the Fabry-Perot etalon resonator 5 into an electrical signal, and a light receiving element 7 converts the output light from the optical multiplexer-splitter 4 into an electrical signal.

Abstract: The purpose of the invention is to offer an optical-frequency-stabilized light source with high accuracy and stability of the optical frequency. An optical splitter 8 splits output light from a local light source 7 into two beams. An optical detector 2 detects beat signals formed by the superimposition of the optical frequency difference between the local light source 7 and the output light, and a rectifier 3 rectifies the beat signal. A time measuring circuit 4 measures the time at which the beat signal was obtained. A frequency measuring circuit 5 measures the beat frequency. A CPU 6 outputs the deviation between the output light from the local light source 7 and the target optical frequency. A Fabry-Perot etalon transmission detection circuit 11 outputs an electrical signal corresponding to the optical frequency of the output light from an optical splitter 9.

Abstract: The object of the invention is to offer a light source device for frequency division multiplexed optical communications having a compact size and reduced cost. Light source units 100-300 output light having optical frequencies which oscillate at mutually different modulation frequencies centered about mutually different optical frequencies. Optical splitters 1-3 split the output light from each light source unit into two parts. An optical multiplexer-splitter 4 multiplexes and splits the output light from the optical splitters. The Fabry-Perot etalon resonator 5 transmits each component of the output light from the optical multiplexer-splitter 4 at a specific transmission rate corresponding to each optical frequency. A light receiving element 6 converts the output light from the Fabry-Perot etalon resonator 5 into an electrical signal, and a light receiving element 7 converts the output light from the optical multiplexer-splitter 4 into an electrical signal.

Abstract: The invention offers an optical fiber amplifier with good frequency characteristics which allows the gain to be held constant even without an input signal beam and allows gain control with respect to input optical signals with high-speed power fluctuations. An excitation beam source 8 supplies an excitation beam for light amplification and a control beam source 15 supplies a control beam for controlling the gain to an EDF 4 which amplifies a signal beam by means of optical excitation. An excitation beam monitor 9 measures the power of the excitation beam when inputted to the EDF 4 and an excitation beam monitor 12 measures the power of the excitation beam when outputted from the EDF 4. A comparator 11 calculates the ratio between the power measured by the excitation beam monitor 9 and the power measured by the excitation beam monitor 12. A drive circuit 14 controls the power of the control beam supplied by the control beam source 15 based on the results obtained by the comparator 11.

Abstract: A noise determination apparatus for simple and precise determination of a noise factor of an optical fiber amplifier is presented. An optical pulse Pin is inputted via an optical coupler 2 into an optical looping circuit 14, and for every loop around the circuit 14, the spontaneous emission light generated in a rare-earth doped optic fiber amplifier 4 is integrated. The amplitude of the light intensity of the optical pulse train outputted from the optical splitter 3 decreases as the looping cycles are increased, and ultimately, the light intensity of the accumulated spontaneous emission light becomes equal to that of the optical pulse train. The pulse train outputted from the photodetector 7 diminishes. The number of pulses in the looping process from the initial pulse train to the expiration event are counted by means of a pulse counting device 8.

Abstract: In an optical sweep signal generator, output beams of a variable-wavelength laser are supplied to an optical branch in which they are divided into first and second beams. The first beam, branched by the optical branch, is delayed by an optical delay line, from which a delayed beam is outputted. An optical mixer mixes the second beam together with the delayed beam so as to produce a mixed beam, which is then supplied to an optical detector. The optical detector performs heterodyne wave detection on the mixed beam. Then, a frequency analyzer performs a frequency analysis on result of the heterodyne wave detection so as to detect heterodyne beat frequency. The variable-wavelength laser is controlled in such a way that the heterodyne beat frequency detected does not vary with respect to time in a selected period of time. Thus, the sweep optical frequency to be realized is varied linearly with respect to time.