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: Provided is a wavelength variable laser device wherein an SOA is simplified. The wavelength variable laser device includes: an optical filter formed on a PLC; an SOA that supplies light to the optical filter; a light reflecting section that returns the light transmitted through the optical filter to the SOA via the optical filter; optical waveguides which are formed on the PLC and connect the SOA, the optical filter, and the light reflecting section; a wavelength variable section that changes a wavelength of the light transmitting through the optical filter; and a phase variable section that changes a phase of the light propagated on the optical waveguides.

Abstract: A method of controlling an optical output of a laser diode includes applying a bipolar current pulse to the laser diode, thereby substantially suppressing the emission tail of the optical output of the laser diode. A device for generating sub-nanosecond intense optical pulses includes a driver unit operative to generate a plurality of bipolar current pulses, and a semiconductor laser diode driven by the bipolar current pulses and operative to emit the intense optical pulses each of which has a substantially suppressed or completely eliminated emission tail.

Abstract: A surface emitting laser includes a plurality of light-emitting portions for emitting laser light beams in different linearly polarized light directions. The light-emitting portions are formed on the substrate and located close to each other. The light-emitting portions include metal opening arrays through which light beams in different linearly polarized light directions respectively pass.

Abstract: In the present invention, the extremely complicated setting and control and an extremely expensive optical component (wavelength locker) are not required, and optical output wavelength and optical output power can simply be set and controlled at a moderate price. At least one value for determining a dependence of the optical output wavelength on drive current and device temperature and at least one value for determining a dependence of the optical output power on drive current and device temperature in a light emitting device constituting first means 1 for emitting light are stored in fourth means 4.

Abstract: The present invention generally relates to the operation of optical network equipment such as optical amplifiers. In one aspect, a method of operating an optical amplifier is provided such that output of the optical amplifier avoids the effects of operating an optical gain medium in a non-linear (kink) region of an L-I curve. The method generally includes operating an optical gain medium in a fully off state or fully on state above the kink region with a PWM signal. In another aspect, the effects of the kink region may be compensated for by utilizing a lookup table. A sample of the optical power of an amplified optical signal may be used to select an entry in the lookup table that compensates for non-linearities in the kink region. In yet a further aspect, a lookup table may be used to control a pulse modulator to compensate for non-linearites in the kink region of the L-I curve.

Abstract: Methods stabilize the output of a pulsed laser system using pulse shaping capabilities. In some embodiments, transient effects following a transition between a QCW regime and a pulse shaping regime are mitigated by ensuring that the average QCW optical power substantially corresponds to the average pulsed optical power outputted in a steady-state operation of the pulsed laser system in the pulse shaping regime. The QCW signal or the pulse shaping signal may be adapted for this purpose. In other embodiments, transient effects associated with non-process pulses emitted between series of consecutive process pulses are mitigated through the proper use of sequential pulse shaping.

Abstract: A laser source is disclosed with coherent recombination of N spatial monomode laser beams having N phase shifters controlled by a phase-lock device (3). The phase-lock device has an optical device (30) capable of taking at least a portion of each of the N beams. The optical device has an optical element (32) capable of applying a phase deformation, and at least one matrix (M1) of detectors capable of detecting a first image (im) of a wave surface corresponding to the N beams. The matrix (M1) of detectors also detects a second image (imd) deformed by the optical element (32). Processing means (31) are provided for processing the first and second images. The processing means are configured so as to measure the phase pistons between on the sub-pupils (spj) corresponding to the N beams and to apply phase corrections c(?) to each of the N beams, by means of said N phase shifters so as to minimize the phase pistons.

Abstract: According to aspects of an embodiment of the disclosed subject matter, a line narrowed high average power high pulse repetition laser micro-photolithography light source bandwidth control method and apparatus are disclosed which may comprise a bandwidth metrology module measuring the bandwidth of a laser output flight pulse beam pulse produced by the light source and providing a bandwidth measurement; a bandwidth error signal generator receiving the bandwidth measurement and a bandwidth setpoint and providing a bandwidth error signal; an active bandwidth controller providing a fine bandwidth correction actuator signal and a coarse bandwidth correction actuator signal responsive to the bandwidth error. The fine bandwidth correction actuator and the coarse bandwidth correction actuator each may induce a respective modification of the light source behavior that reduces bandwidth error. The coarse and fine bandwidth correction actuators each may comprise a plurality of bandwidth correction actuators.

Abstract: A pulsed laser is disclosed comprising an active lasing medium (1), an output coupler (5) and a rear cavity mirror (6). The rear cavity mirror (6) is attached to a mount (21) via an intermediate attachment (15). Heating elements are embedded within the attachment (15). The attachment (15) is heated in order to vary the physical length of the laser cavity in a manner which seeks to stabilise the output energy and wavelength of the laser pulses emitted from the laser cavity.

Abstract: A method and apparatus for modifying the out of band reflection of a laser element is described. The laser element includes an active medium excited by optical pumping means to produce stimulation emission of light. The laser element further includes a Bragg grating structure for providing optical feedback for the active medium, with the Bragg grating structure including a phase transition region providing a change in phase. The change in phase of the phase transition region is adjusted to modify out of band reflection of said laser element.

Abstract: A light source and the method for operating the same are disclosed. The light source includes first and second lasers, and first and second wavelength control assemblies. The lasers emit first and second light beams, respectively, at wavelengths that are determined by first and second wavelength control signals. First and second beam splitters split the first and second light beams, respectively, to create first and second sampling light beams. The first and second wavelength control assemblies receive sampling light beams and generate the first and second wavelength control signals such that the wavelengths of the first and second light beams differ by no more than a predetermined amount. The first and second wavelength control assemblies each include an absorption cell having a gas that has an optical absorption that varies with the wavelength of the first and second sampling light beams at wavelengths around the output wavelength of the light source.

Abstract: In a coherent light projection system including an image forming system, a relay system, a speckle reduction element, and a projection subsystem, the relay system can have a first f-number, and the projection subsystem can have a second f-number less than the first f-number. The relay system can have a first working distance, and the projection subsystem can have a second working distance less than the first working distance. The image forming system can project an initial image having a first size, and an intermediate image can have a second size greater than or equal to the first size. The speckle reduction element can have a curved surface through which the intermediate image is transferred. The speckle reduction element can include a lenslet arrangement formed on a surface thereof. The speckle reduction element can be moved in a direction parallel to an optical axis of the speckle reduction element.

Abstract: Exemplary embodiments provide a method and system for controlling laser power in an optical disc drive. The exemplary embodiment of a control system includes at least one control component for generating a control signal; a plant for generating a control output responsive to the control signal; and a dual feedback control loop coupled between the control output of the plant and the control component, the dual feedback control loop comprising a combination of a running optimal power control (ROPC) loop, and an automatic power control (APC) loop that run concurrently for generating respective feedback control signals that are input to the control component for generation of a combined control signal adjustment that is used at least in part to generate the control signal.

Abstract: A laser frequency stabilizing device comprises a laser light producer operative to produce and emit a laser light containing a first and a second longitudinal mode light having different wavelengths; a spectrometer operative to spectrally decompose the laser light into the first longitudinal mode light and the second longitudinal mode light; a first detector operative to detect the light output signal from a absorption cell; a second and third detector operative to detect the signal intensity of the first and second longitudinal mode light; an actuator operative to change the resonant cavity length; a first drive controller operative to detect the saturated absorption signal from the light output signal detected at the first detector and control driving the actuator based on the saturated absorption signal; a second drive controller operative to control driving the actuator such that the signal intensity of the first longitudinal mode light detected at the second detector and the signal intensity of the secon

Abstract: This description relates to an apparatus, a method of manufacturing, and a method of tuning optical and/or electrical parameters of semiconductor devices and materials, thin film materials, or other devices. In one example, a laser is tuned to produce an adjustable output wavelength by coupling the laser to a tuning material or base such as, for example, a piezoelectric base using a suitable attachment method. The laser includes of a tunable material that is sensitive to stress and/or strain. Stress and/or strain applied to the laser from the tuning material results in an electronically variable output wavelength. As an example, applying a voltage to a piezoelectric base that serves as a tuning material can cause the base to expand or contract, and the expansions and contractions from the base are coupled to the tunable material of the laser, thus varying the wavelength of the output light from the laser.

Abstract: A semiconductor laser excitation solid laser control device 1A according to the present invention is a control device for stabilizing a light quantity of an output light LO of a semiconductor laser excitation solid laser 2. The control device 1A comprises: a beam splitter 11A for branching a laser light emitted from the semiconductor laser excitation solid laser 2 into the output light LO and a control light LC; a light reception element 12 for detecting the light quantity of the control light LC branched by the beam splitter 11A; and control means 13 for controlling the light quantity of the laser light emitted from the semiconductor laser excitation solid laser 2 so that the light quantity detected by the light reception element 12 will be constant. The beam splitter 11A has a transmittance and a reflectivity not depending on the polarization characteristic of the laser light.

Abstract: A method and circuit is disclosed for a laser system wherein the power of the laser signal is kept at a constant near optimum value and a portion of an frequency doubled output signal is monitored and detected so that noise within the frequency doubled output signal can be minimized. A feedback signal is used to dither the temperature of a frequency doubled crystal so as to minimize the noise in the frequency doubled output signal.

Abstract: A method of operating a laser projection system is provided. The projection system comprises an external cavity laser, an optical intensity monitor, laser projection optics, and a controller. The external cavity laser comprises a laser diode, an intra-cavity wavelength conversion device, and a wavelength selective element. According to the method, the position of the wavelength selective element is adjusted relative to an optical axis Z of the external cavity laser to optimize output intensity. Specifically, the position of the wavelength selective element is adjusted by (i) tilting the wavelength selective element about its wavelength selective axis Y to reflect a wavelength of interest along an optimum path in an XZ plane of the external laser cavity and (ii) tipping the wavelength selective element about its wavelength insensitive axis X to reflect the wavelength of interest along an optimum path in a YZ plane of the external laser cavity. Additional embodiments are disclosed and claimed.

Abstract: According to aspects of an embodiment of the disclosed subject matter, method and apparatus are disclose that may comprise adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, without utilizing any beam magnification control, or adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, while utilizing beam magnification control for other than bandwidth control, and adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, while utilizing beam magnification control for bandwidth control based on the error signal.

Abstract: The temperature of a laser diode changes in response to video content across a line of a displayed image, and the radiance changes as a function of temperature. An adaptive model estimates the temperature of the laser diode based on prior drive current values. For each displayed pixel, diode drive current is determined from the estimated diode temperature and a desired radiance value. A feedback circuit periodically measures the actual temperature and updates the adaptive model.

Abstract: A fiber output stabilizer according to an aspect of the invention stabilizes output light from a rare-earth doped optical fiber in which at least one kind of a rare-earth element is added to a core. The fiber output stabilizer includes: a monitoring light source that emits monitoring light having a wavelength shorter than that of excitation light exciting the rare-earth element; an optical multiplexer that multiplexes the monitoring light into the excitation light; an optical demultiplexer that demultiplexes the monitoring light passing through the rare-earth doped optical fiber; and a passing light detector that detects light intensity of the monitoring light from the optical demultiplexer.

Abstract: A semiconductor laser having an oscillation wavelength ? (nm) and comprising at least a substrate, a first-conduction-type clad layer having an average refractive index N1cld, an active layer structure having an average refractive index NA, and a second-conduction-type clad layer having an average refractive index N2cld. This has a first-conduction-type subwave guide layer having an average refractive index N1SWG between the substrate and the first-conduction-type clad layer, and has a first-conduction-type low-refractive-index layer having an average refractive index N1LIL between the subwaveguide layer and the substrate. In this, the refractive indexes satisfy specific relational formulae. The semiconductor laser has a stable oscillation wavelength against the change of current/light output/temperature.

Abstract: In an optical supply arrangement, a laser source (10) provides transmitted laser light down an optical supply line (12, 14). A first coupler (16), remote from the laser source (10) along the optical supply line (14), taps off a small proportion of the transmitted laser light to be returned along the optical supply line (14) to a photo detector (26) driving a monitor (28) and a controller (30). If the monitor (28) detects that the photo detector (26) is experiencing a loss of return laser light, possibly due to a break in the optical supply line (14), the monitor (28) causes the controller (30) to extinguish the laser source (10) in less time than escaping laser light can cause damage to property, person or eyesight. A first embodiment has the transmitted light on a transmission fiber optic (12) and the return laser light on a separate return fiber optic (24). A second embodiment has the return laser light being sent back down the transmission fiber optic (12).

Abstract: This invention discloses a method to control laser dynamics in a gain-switched fiber laser so as to generate stable, clean pulses in an all-fiber format. The gain-switched fiber laser is suitable as a standalone laser source, and as a pump source for harmonic generation and an optical-parametric-oscillator.

Abstract: A solid-state gain element including a thin doped region in which an optical signal propagates through the thin doped region at a large angle with respect to the normal to the thin doped region, reflects at a boundary of the thin doped region, and passes through the thin doped region again. An optical pump beam propagates through the thin doped region also at a large angle with respect to the normal to the thin doped region. In one example, the gain element and source of the pump beam are configured such that there is total internal reflection of the pump beam at the boundary of the thin doped region for a second pumping pass through the thin doped region. In another example, an elliptically symmetric laser beam is used to create a circularly symmetric gain region in the thin doped region.

Abstract: An optically pumped, surface-emitting semiconductor laser having a mode-selective apparatus (7) which is intended for suppression of predeterminable, higher resonator modes of the semiconductor laser. The mode-selective apparatus is arranged in the beam path of a pump beam source (2) of the surface-emitting semiconductor laser.

Abstract: A doped superfluorescent fiber source (SFS) has an enhanced mean wavelength stability. A method stabilizes the mean wavelength of a SFS. The method includes providing an SFS including a doped fiber. The method further includes pumping the SFS with pump light from a pump source having a wavelength dependent on the temperature of the pump source and dependent on the power of the pump light. The method further includes optimizing the length of the fiber to reduce the influence of the pump light wavelength on the stability of the mean wavelength.

Abstract: A high-power laser system includes a laser master oscillator, a plurality of fiber laser amplifiers producing intermediate output beamlets, a combiner for combining the intermediate beamlets into a combined output beam, and a piston error controller for minimizing errors related to beam combination that may degrade the quality of the combined output beam. A piston error controller processes a sample of the combined output beam using a Diffractive Optical Element to isolate a signal representing the total piston error of the combined beam. The controller uses amplitude modulation based on Hadamard code words to tag each non-reference intermediate beamlet with a unique code sequence orthogonal to those used for the other beamlets. For each intermediate beamlet, the associated piston error contribution is recovered using a Hadamard decoder. A very small phase dither is also introduced to allow the sign or direction of the piston error to be recovered.

Abstract: Multi-channel Fabry-Perot laser transmitters and methods of generating multiple modulated optical signals are described. In one aspect, an optical transmitter includes a Fabry-Perot (FP) laser, an optical isolator, an optical splitter, and multiple electroabsorption modulators (EAMs). The FP laser is operable to generate multimode laser light. The optical isolator is arranged to transmit the multimode laser light. The optical splitter has more than one optical output and an optical input that is arranged to receive the multimode laser light transmitted by the optical isolator. Each of the EAMs is operable to modulate a respective laser light output from a respective optical output of the optical splitter. In another aspect, multimode laser light is generated. The multimode laser light is directionally isolated. The directionally-isolated multimode laser light is divided into more than one divided laser light output.

Abstract: A phase-conjugating resonator that includes a semiconductor laser diode apparatus that comprises a phase-conjugating array of retro-reflecting hexagon apertured hexahedral shaped corner-cube prisms, an electrically and/or optically pumped gain-region, a distributed bragg reflecting mirror-stack, a gaussian mode providing hemispherical shaped laser-emission-output metalized mirror. Wherein, optical phase conjugation is used to neutralize the phase perturbating contribution of spontaneous-emission, acoustic phonons, quantum-noise, gain-saturation, diffraction, and other intracavity aberrations and distortions that typically destabilize any stimulated-emission made to undergo amplifying oscillation within the inventions phase-conjugating resonator. Resulting in stabilized high-power laser-emission-output into a single low-order fundamental transverse cavity mode and reversal of intra-cavity chirp that provides for high-speed internal modulation capable of transmitting data at around 20-Gigabits/ps.

Abstract: A high power integrated fiber laser system includes cascaded amplifiers that utilize low numerical aperture fiber amplifiers. The system is rugged and lightweight.

Abstract: A method for controlling wavelengths of a multi-path laser is provided. The method includes: obtaining a difference between an actual output wavelength and a target output wavelength of each laser (S601); obtaining a corrected control amount of a temperature controller of each laser by decoupling calculation according to the difference (S602); and determining a die temperature of each laser according to the corrected control amount of the temperature controller (S603). A system for controlling wavelengths of a multi-path laser includes a multi-path laser (10), a difference module (12), a decoupling module (14), and a temperature control module (16).

Abstract: A wavelength tunable laser module for DWDM is used, in which a single electroabsorption modulator integrated laser is mounted and an oscillation wavelength is made tunable by temperature control. Driving conditions of a laser and a modulator are determined such that they have approximately the same modulation and transmission characteristics in a temperature control range. Such an electroabsorption modulator integrated laser is used and the driving conditions are incorporated, thereby a small, inexpensive wavelength tunable optical transmitter can be provided.

Abstract: A laser transmitter with a feedback control loop for minimizing noise. The novel laser transmitter includes a laser, an external reflector adapted to form an extended cavity to the laser, and a feedback control loop adapted to detect noise in the laser and in accordance therewith, adjust the optical phase of the extended cavity such that the noise is at a desired level. The optical phase of the extended cavity is adjusted by adjusting an operating parameter of the laser, such as its bias current. In an illustrative embodiment, the feedback control loop is adapted to compute the rate of change of the noise with respect to bias current and in accordance therewith, adjust the bias current of the laser such that relative intensity noise and interferometric intermodulation distortion are simultaneously minimized.

Abstract: Systems and methods for stripping an optical mode from a semiconductor laser. A waveguide layer with multiple layers is included in the semiconductor laser and is typically arranged beneath the active region. The waveguide layer is configured to match the phase of the second order mode. The waveguide layer does not substantially match the primary optical mode of the laser. By matching the phase of the second order mode, the confinement of the second order mode is reduced and the second order mode strongly couples with the waveguide layer. The optical confinement of the primary mode is not substantially reduced. The side-mode suppression ratio is thereby improved by stripping the second order mode from the active region.

Abstract: A modular ultrafast pulse laser system is constructed of individually pre-tested components manufactured as modules. The individual modules include an oscillator, pre-amplifier and power amplifier stages, a non-linear amplifier, and a stretcher and compressor. The individual modules can typically be connected by means of simple fiber splices.

Abstract: Apparatus for attenuating an unpolarized laser beam includes a polarizing beamsplitter for separating the laser beam into two plane-polarized beams following separate paths. The two plane-polarized beams are polarization rotated by a single polarization rotator. Each of the polarization-rotated beams is separated by a polarizing beam-combiner into two plane-polarized portions. One of the portions of one polarization-rotated beam is combined by the beam-combiner with one of the portions of the other polarization-rotated beam to provide an attenuated output-beam. In certain examples of the apparatus the separate paths are made equal in length so that combined beam portions are equal in diameter.

Abstract: A controller (7) is disclosed for controlling the power supply to a laser (3) that is used in determining the motion of an object (8). The controller comprises a power source (2) that is arranged to supply power pulses (10, 11) to the laser (3) in response to a controller signal. The controller (7) controls the generation of pulses to those periods in which a reliable result can be obtained, by detecting the laser radiation that has interacted with pulses reflected from the object (8), in order to conserve power consumption. Further the power pulses (10, 11) comprise a heating component (9), which serves to stabilize the temperature of the laser (3) and therefore calibrate the laser (3) so that a known lasing wavelength is generated.

Abstract: Apparatus for stabilizing carrier-envelope phase (CEP) of laser pulse generated by mode locked pulsed laser based on direct locking method includes laser oscillator, interferometer, detector and double feedback circuit. The laser oscillator includes the mode locked pulsed laser generating the laser pulse. The interferometer generates laser pulses having first and second frequency components from the laser pulse generated by the mode locked pulsed laser to generate first and second interference signals that substantially correspond to each other in time domain and space domain. The detector receives the first and second interference signals to output third and fourth interference signals by inverting phase of the second interference signal. The double feedback circuit controls the laser oscillator so that the CEP of the laser pulse generated by the mode locked pulsed laser has substantially constant value with respect to time using CEP signal obtained from the third and fourth interference signals.

Abstract: Methods and devices for a coupled optoelectronic oscillator having optical frequency stabilization. The coupled optoelectronic oscillator includes a harmonically mode-locked laser cavity having a Mach-Zehnder modulator for mode-locking and an intracavity Fabry-Perot etalon to allow only one single supermode to lase, a stabilization loop coupled with the Fabry-Perot etalon to detect changes in the laser cavity optical frequency and generate an error signal to compensate for the frequency change to stabilize the mode-locking of the laser frequency stabilization, and an electrical loop between the laser cavity and the stabilization loop for driving the Mach-Zehnder modulator with the coupled optoelectronic oscillator signal.

Abstract: The performance of a laser scanner is optimized in the field by automatically determining appropriate laser parameters for the scan location. A laser control system uses information such as the environmental temperature to select an appropriate range of start points for various laser parameters, such as pump temperature and laser currents. Test pulses over that range can be used to determine optimal operating parameters.

Abstract: Apparatus and methods for altering one or more spectral, spatial, or temporal characteristics of a light-emitting device are disclosed. Generally, such apparatus may include a volume Bragg grating (VBG) element that receives input light generated by a light-emitting device, conditions one or more characteristics of the input light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light.

Abstract: The invention relates to a method for controlling an oscillatory system with the aid of at least one measured variable by the detection of at least one oscillation component (Sx(t)) over time (t) in the form of at least one measured variable. According to said method a control variable (?u) for controlling the oscillatory system is determined from the sum of the weighted differences of the delayed oscillation component, which has been delayed at least twice by different delay times (?1>O, ?2>0) if there is one measured variable and the respective non-delayed oscillation component and if there are several measured variables the sum of the weighted differences of the delayed oscillation components (Si(t??i)), which have been respectively delayed at least once by a specific delay time (?i>0) and their respective non-delayed oscillation components (Si(t)) according to the relationship ?u=a1S1(t) b1S1(t??1)+ . . . +anSn(t)?bnSn(t??n), wherein a1, . . . , an and b1, . . .

Abstract: A self-calibrating integrated photonic circuit and a method of controlling the same. In one embodiment, the circuit includes: (1) a substrate, (2) a laser located on the substrate and configured to produce source light at an output frequency, (3) a laser alignment sensor located on the substrate and including: (3a) a reference optical resonator configured to receive the source light, have a null proximate a predetermined center frequency and provide output light as a function of a relationship between the output frequency and the center frequency and (3b) a photodetector configured to provide an electrical signal of a magnitude that is based on the output light and (4) a calibration controller located on the substrate, coupled to the photodetector and configured to adjust the output frequency based on the magnitude.

Abstract: An object is to provide a light source unit that focuses a laser beam having different divergence angles in longitudinal direction and lateral direction, without deviating longitudinally and laterally from an incident end-face of an optical fiber, and also that simplifies assembling lenses into a lens barrel. The light source unit herein provided includes a first lens barrel 1 that holds cylindrical lenses 10 and 11, and 12 for forming a parallel-ray laser beam by refracting the laser beam 9 having different divergence angles in longitudinal direction and lateral direction emitted from a laser element 7, a second lens barrel 2 that holds circular lenses 13 and 14 for focusing the parallel-ray laser beam onto the entrance of the optical fiber 3, and a lens holder 15 that holds at least one of the cylindrical lenses and is inserted into the first lens barrel 1 and fixed therein.

Abstract: An optical transmitter module includes a semiconductor laser for outputting forward outgoing light and backward outgoing light, a temperature control device for controlling a temperature of the semiconductor laser, a beam splitter plate for receiving incidence of the backward outgoing light and outputting split light, which is reflected part of the backward outgoing light and transmitted light, which is part of the backward outgoing light, a first photoelectric conversion element for converting the split light into an electric signal. The beam splitter plate includes an anti-stray-light structure for preventing the transmitted light reflected by an incident surface of a wavelength filter from entering the first photoelectric conversion element through a side end surface portion of the beam splitter plate.

Abstract: Various embodiments described herein relate to a laser source for producing a pulsed laser beam comprising a plurality of ultrashort optical pulses having a variable repetition rate. In one embodiment, the laser source comprises a fiber oscillator, which outputs optical pulses and a pulse stretcher disposed to receive the optical pulses. The optical pulses have an optical pulse width. The pulse stretcher has dispersion that increases the optical pulse width yielding stretched optical pulses. The laser source further comprises a fiber amplifier disposed to receive the stretched optical pulses. The fiber optical amplifier has gain so as to amplify the stretched optical pulses. The laser source includes an automatically adjustable grating compressor having dispersion that reduces the optical pulse width. The grating compressor automatically adjusts this dispersion for different repetition rates.

Abstract: Laser light (?L) within a spectrum range is generated (51g) and filtered (29g). Thereby the spectral location of the filter characteristic (?F) is shifted in a controlled manner (60) to establish a desired characteristic of output laser light as for considering a temperature depended shift (?Ñ) of the spectrum range generated by the laser source (51g).

Abstract: A driver laser for EUV light source apparatus which driver laser simultaneously achieves short-pulsing and multi-line oscillation. The driver laser includes: a short-pulse multi-line oscillated CO2 laser oscillator having a device that shortens width of pulses included in a laser beam to be output and a device that suppresses amplitude of an oscillation spectrum exhibiting an energy peak value; and at least one amplifier that inputs the laser beam output from the short-pulse multi-line oscillated CO2 laser oscillator and amplifies the input laser beam to output the amplified laser beam.