Abstract: The invention provides an once through fan for an excimer laser apparatus having a reduced vibration and being capable of increasing a rotational speed. In order to obtain this, in an once through fan (1) for an excimer laser apparatus provided with a blade portion (6) having a plurality of blades, a rotary shaft (4) for rotating the blade portion and a magnetic bearing (7) rotatably supporting the rotary shaft in a non-contact manner so as to circulate a laser gas sealed within a chamber (2) in accordance with a rotation of the blade portion, a rotor (21) of a motor (23) installed within the chamber (2) and rotating the rotary shaft (4) is mounted on an outer peripheral portion of the rotary shaft, and at least one magnetic bearing (7, 7) for supporting the rotary shaft is arranged in each of both sides in an axial direction of the rotor.

Abstract: A semiconductor laser module of an external-cavity type in which a GaAs/AlGaAs-based semiconductor laser having ripples in the gain-wavelength characteristic thereof and an optical transmission medium including a Bragg grating are optically coupled by an optical coupling member.

Abstract: An active layer in which laser light is generated by injecting driving current therein is sandwiched between semiconductor layers. The active layer has a multi-quantum-well structure, and the layers located at both sides of the active layer are made of an AlGaAs-based material. Refractive indices of the layers are set asymmetrically with respect to the active layer by properly selecting aluminum-mixing ratios in AlGa. Since the light generated in the active layer is distributed more in a layer having a higher refractive index, a peak of the light distribution is shifted from the active layer into the layer having a higher refractive index. Thus, energy concentration to the active layer is avoided. A thickness of the layer having a higher refractive index may be made thicker to further enhance the energy concentration shift from the active layer.

Abstract: A forward mesa ridge-embedded semiconductor laser device provides a high power output and includes a base portion of a forward mesa ridge having a narrow width to stabilize transverse mode oscillation and an upper cladding layer having a thickness sufficient to reduce loss of the laser beam, a top portion of the forward mesa ridge being interposed between parts of the current blocking layer to reduce the device resistance. The upper cladding layer includes a first cladding layer having the forward mesa ridge and a second cladding layer opposite the first cladding layer. The second cladding layer is deposited over the first cladding layer through the forward mesa ridge and a current blocking layer is positioned on both sides of the forward mesa ridge.

Abstract: The present invention demodulates a FM, WM or AM optical input beam, amplifies the signal impressed on the beam, and then modulates without intervening electronics the signal amplitude of an output beam. The apparatus can be made from any semiconductor laser, including edge-emitting lasers and VCSELs. Light transmitted through the waveguide (the “control beam”) interacts with the carrier population of the laser, reducing the available gain and thereby the output intensity. The present invention has three key advantages: (i) a FM control beam produces an amplitude-modulated output beam from the main-laser, (ii) the amplitude of the AM beam depends directly on the differential gain ∂G/∂&ohgr;, and (iii) the apparatus and method provides gain for all LOGiC devices. The present invention works with available and future semiconductor lasers, including those emitting in the blue as well as those operating at 670, 850, 980, 1300, and 1500 nm.

Abstract: A gas laser oscillator having at least three discharge tubes disposed along the optical axis, and a spacer having an opening centered on the optical axis. The spacer is disposed between a partially reflective mirror and the closest discharge tube. Further, the discharge tubes are disposed in series along the optical axis, and satisfy the following three formulas simultaneously: r1/r2>1.0  Formula 1 L2/(L1+L2)<0.85  Formula 2 r3/r2<1.4  Formula 3 where the sum of lengths of a pair of discharge tubes disposed at both ends in optical axis direction is L1, the inside diameter of these discharge tubes is r1, the sum of lengths of the other discharge tubes in the optical axis direction is L2, the inside diameter of these discharge tubes is r2, and the inside diameter of the opening of the spacer is r3.

Abstract: Lasers comprising a substrate and a layer of organic material over the substrate. The organic material includes host and dopant materials that result in the laser emission of a desired color when pumped by optical pump energy. Host materials include CBP and tris-(8-hydroxyquinoline) aluminum, which when combined with dopant materials such as coumarin-47, coumarin-30, perylene, rhodamine-6G, DCM, DCM2, and pyrromethane-546 result in the efficient lasing of colors such as blue, green and yellow.

Abstract: A laser device includes a laser rod; a radial array of diode laser pumping devices, wherein each diode laser has a solid connection to the laser rod to maximize laser energy transfer. The diode laser radial array is serially connected via coatings and/or fingers and/or spheres. Cooling of the laser rod and the diode laser radial array is accomplished via a common fluid channel outside the laser rod, wherein a cooling fluid flows past the laser rod and the diode laser radial array. Innovative methods for creating the coating embodiments are disclosed. Various flat diode laser embodiment are also disclosed.

Abstract: The effectiveness of reflected light to stabilize the operational characteristics of a semiconductor diode laser varies with the polarization orientation of the reflected light. Stabilization failure can occur if the polarization orientation of the reflected light is orthogonal to the polarization of the light emitted by the laser source. The use of multiple reflectors can reduce the probability of stabilization failure by arranging the reflectors to return to the laser source portions of light having polarization orientations that are statistically independent with respect to each other.

Abstract: A distributed feedback semiconductor laser (DFB laser) in which light feedback is performed by using a diffraction grating, and in which influence of external feedback noises can be decreased to suppress fluctuation of an optical output. The DFB laser comprises a diffraction grating structure portion which constitutes a resonator and which is divided into a plurality of regions along the longitudinal direction of the resonator, and one or more phase shift portions each disposed between adjacent regions of the diffraction grating structure portion, wherein total phase shift obtained by all of the phase shift portions has a quantity corresponding to &lgr;/n, where &lgr; is an oscillation wavelength, and n is an integer larger than 4 (n>4). The total phase shift may have a quantity corresponding to a value within a range between &lgr;/5 and &lgr;/8.

Abstract: A laser diode pump for fiber amplifiers, such as erbium-doped fiber amplifiers (EDFAs), reduces spurious reflections in the signal frequencies by providing a laser pump system that is dissipative at these signal frequencies. Reflections from the pump system are reduced, or eliminated by using an output facet that is currently coated to be reflective at pump frequencies, but anti-reflective, or transmissive, at the signal frequencies. In one embodiment, material layers of aluminum oxide (Al2O3), titanium dioxide (TiO2), and silicon dioxide (SiO2) are used.

Abstract: A face-cooling scheme is used with multiple nonlinear crystal formats used primarily for second harmonic generation without the need for air-path rephasing between the crystals. Birefringent crystals, e.g., MgF2, are cut and oriented such that there is no dispersion between the fundamental and second harmonic wavelengths within each crystal. The crystals are then disposed in a heat-conducting housing sandwiched by two or more nonlinear crystals and used as the face-cooling medium, thereby causing the heat generated in the nonlinear crystals by absorption at the fundamental and second harmonic wavelengths to flow longitudinally (direction of beam propagation) into the face-cooling medium. This minimizes any transverse thermal gradient in the nonlinear crystals and the attendant dephasing loss. The crystals can be dry stacked with a very small gas-filled gap, immersed in a liquid or gel, bonded with optical cement, optically contacted, or diffusion-bonded together to form a composite crystal.

Abstract: The gas laser oscillator of the invention comprises a discharge tube, a pair of electrodes disposed at both ends thereof, a direct-current high voltage power source for applying a direct-current high voltage in pulse form to the pair of electrodes, an output control device for controlling the direct-current high voltage power source, a fully reflective mirror provided at one end of the outside of the pair of electrodes, a partially reflective mirror disposed at other end of the outside of the pair of electrodes, and an absorber disposed outside of the partially reflective mirror. In thus constituted gag laser oscillator, the output control device controls to apply a same direct-current voltage as during processing between the pair of electrodes also on standby while the absorber is closed.

Abstract: Laser source including materials with negative index of refraction dependence on temperature and with temperature independent coincidence between cavity modes and a set of specified frequencies such as DWDM channels in telecommunications applications. The free spectral range may be adjusted to equal a rational fraction of the specified frequency interval. The operating frequency may be defined by a frequency selective feedback element that is thermo-optically tuned by the application of heat from an actuator without substantially tuning the cavity modes. The operating frequency may be induced to hop digitally between the specified frequencies. In a particular embodiment, semiconductor amplifier and polymer waveguide segments form a linear resonator with a thermo-optically tuned grating reflector. In a further embodiment, an amplifier and two waveguides from a tunable grating assisted coupler form a ring resonator.

Abstract: A light emitting semiconductor element comprises a first additive layer which is added into a cladding layer or a middle layer. The first additive layer has a lattice constant which is different from a lattice constant of a semiconductor substrate. The light emitting semiconductor element is attached to a heat sink to form a laser device. The heat sink gives deformation to the light emitting semiconductor element. The first additive layer generates strain therein and suppresses influence of the deformation.

Abstract: A frequency stabilized laser using an integrated external cavity, comprising a semiconductor laser diode and an optical waveguide installed on the same substrate, and having an optically induced grating formed in the optical waveguide suppresses mode hopping due to a temperature change to stabilize the oscillation frequencies of the laser. A material having a refractive index temperature coefficient opposite in sign to the refractive index temperature coefficient of the semiconductor laser diode is installed on that portion of the optical waveguide between the semiconductor laser diode and the optically induced grating which has been formed by removing an upper cladding and a core, or removing the upper cladding, the core, and a lower cladding.

Abstract: A surface emitting semiconductor laser and a surface emitting semiconductor laser array having a photodetector capable of monitoring the light output of a laser easily at a high speed without deteriorating the performance of a surface emitting laser. An n type GaAs optical absorbing layer having an opening in the center of a waveguide path is inserted between the p type DBR layer and the spacer layer of the surface emitting semiconductor laser as a light receiving part and a PD electrode which takes out electrons generated in this optical absorbing layer is formed on the optical absorbing layer.

Abstract: A semiconductor laser structure based upon a rib waveguide geometry which includes a uniform region and a flared and tapered region. The uniform region has a generally constant thickness and width. The flared tapered region gradually increases in width and decreases in thickness from the uniform region to a wide end. Fabrication is by selective area epitaxy with dielectric stripes in a dual stripe dielectric mask used to defined the two dimensional varying flare in the waveguide changing in thickness as a function of the flare width.

Abstract: Disclosed is a laser system including a high reflector and an output coupler defining a resonator; a gain medium positioned in the resonator that produces optical gain at more than two desired wavelengths; a coarse selection system, positioned in the resonator and coupled to the gain medium, that produces single transverse modes at the desired wavelengths, with transmission values at the desired wavelengths selected such that power output at the desired wavelengths is maximized, and with transmission values at undesired wavelengths selected to retard lasing at the undesired wavelengths; and a fine selector positioned in the resonator and coupled to the gain medium, having a optical length such that all of the desired wavelengths are substantially simultaneously resonant within the optical length; whereby an output beam is generated. Also disclosed are full-color holography systems and three-dimension laser Doppler velocimetry systems incorporating the inventive laser system.

Abstract: A sub-mount, an LD bar and a light guide duct are mounted on an LD package main body of a semiconductor laser, and an outgoing section of the LD bar is inserted into the light guide duct. A gold metallized insulating plate is fused on one side of the LD package main body, and the LD bar and the gold metallizing are wire-bonded. The light guide duct transmits the excitation light directly up to a laser medium, and a reflector surrounds the periphery of the laser medium. Upon flowing of a current from the LD package main body to the cathode electrode, the LD excitation light is emitted and the laser medium is excited, to thereby make laser oscillation possible. With the above structure, there is provided an LD excitation solid-state laser device which is easy in assembling, low in the costs, high in efficiency and high in reliability.