Abstract: In a semiconductor laser device having an oscillation wavelength of larger than 760 nm and smaller than 800 nm, on an n-type GaAs substrate (101), there are stacked in sequence an n-type first and second lower cladding layers (103, 104), a lower guide layer (106), a strained InGaAsP multiquantum well active layer (107), an upper guide layer (109), and a p-type upper cladding layer (110). Since the lower guide layer (106) is formed of InGaP, leakage of carriers from an active region is reduced. Also, since the upper guide layer (109) is formed of AlGaAs, an overflow of carriers (electrons in particular) is suppressed.

Abstract: The present invention offers a laser oscillator device having sufficient cooling ability to maintain a lasing medium which generates high-density thermal energy at a temperature appropriate for use, while being capable of being made compact. The laser oscillator device comprises an excitation beam source for generating an excitation beam, a laser medium for receiving the excitation beam and performing optical amplification, a laser oscillator device for causing resonance of light emitted by the laser medium for laser oscillation, and a cooling system for cooling said laser medium, wherein the cooling system uses a gas as the heat-carrying medium.

Abstract: A method for maintaining the mode-locked state of a Fabry-Perot (FP) laser and a WDM light source using the same method for use in WDM optical communication are disclosed. The mode-locked state can be maintained irrespective of temperature change, without use of a temperature controller, by spectrum-slicing the incoherent light generated by a light source element and injecting the spectrum-sliced light to the FP laser, then the FP laser amplifies and outputs only a lasing mode coinciding with the wavelength of the injected light, wherein a lasing-mode interval of the FP laser is set to be less than a 3 dB linewidth of the injected light, so that at least one lasing mode exists inside the 3 dB linewidth of the injected light irrespective of changes in external temperature.

Abstract: A tunnel junction structure comprises an n-type tunnel junction layer of a first semiconductor material, a p-type tunnel junction layer of a second semiconductor material and a tunnel junction between the tunnel junction layers. The first semiconductor material includes gallium (Ga), nitrogen (N), arsenic (As) and is doped with a Group VI dopant. The probability of tunneling is significantly increased, and the voltage drop across the tunnel junction is consequently decreased, by forming the tunnel junction structure of materials having a reduced difference between the valence band energy of the material of the p-type tunnel junction layer and the conduction band energy of the n-type tunnel junction layer. Doping the first semiconductor material n-type with a Group VI dopant maximizes the doping concentration in the first semiconductor material, thus further improving the probability of tunneling.

Abstract: An electra-absorption modulator and electra-absorption modulated laser are described that include a semiconductor layer having an electrically controllable absorption. The material composition of the semiconductor layer is chosen so that the semiconductor layer is substantially transparent to light propagating through the semiconductor layer when a substantially zero or a reverse bias voltage is applied across the semiconductor layer at operating temperatures of the electro-absorption modulator that are substantially greater than 25 degrees Celsius.

Abstract: An improved singlet delta oxygen generator (SOG) and method of its use are disclosed. The improved SOG is compact and scalable, capable of operating in a zero-gravity or low gravity environment, requires no gaseous diluent or buffer gas, and is capable of operating at pressures as high as one atmosphere. The improved SOG also efficiently utilizes the reactants and produces a O2(1?) stream that is largely free of chlorine and water vapor contamination and therefore does not require a BHP regeneration system or a water vapor trap. When used as part of a COIL system, the SOG may be part of a plenum that directly feeds the laser's nozzle. The close proximity of the SOG to the laser cavity allows operation of the SOG at higher pressures without significant depletion of available O2(1?) through collisional deactivation.

Abstract: A transmitter array that has at least one pixel element. Each pixel element includes at least a primary semiconductor laser and a secondary semiconductor laser. In this manner, when the primary semiconductor laser is inoperative, the secondary semiconductor laser is utilized for transmission.

Abstract: Embodiments of the present invention are directed to staggered arrays of laser diode bars positioned on stepped support structures. Optical waveguides may direct the outputs of the individual diode bars to a desired location, for example, a common output plane. The optical waveguides may be glass plates in certain embodiments. Waste heat generated by the diode bars may be removed from the support structures at certain locations and as a result, the diode bars may be closely positioned with respect to each other. By closely positioning the laser diode bars and directing the diode bar outputs to a desired orientation, the effective brightness and fluence may be increased for a given output area and operational power compared to the prior art. Associated methods of manufacturing staggered array couplers and producing high-power pump energy are also described.

Abstract: A method of evaluating a laser comprises providing a current into the laser and measuring a voltage output of an electroabsorptive modulator (EAM) coupled to the laser. A device under test includes a laser, and an electroabsorptive modulator (EAM), wherein said EAM monitors an output of said laser.

Abstract: A nitride-based semiconductor light-emitting device capable of stabilizing transverse light confinement is obtained. This nitride-based semiconductor light-emitting device comprises an emission layer, a cladding layer, formed on the emission layer, including a first nitride-based semiconductor layer and having a current path portion and a current blocking layer, formed to cover the side surfaces of the current path portion, including a second nitride-based semiconductor layer, while the current blocking layer is formed in the vicinity of the current path portion and a region having no current blocking layer is included in a region not in the vicinity of the current path portion. Thus, the width of the current blocking layer is reduced, whereby strain applied to the current blocking layer is relaxed. Consequently, the thickness of the current blocking layer can be increased, thereby stabilizing transverse light confinement.

Abstract: A laser system for generating at least one pulse and/or pulse sequence(s) of pulses having at least one specified property, such as pulse energy, duration, peak intensity, pulse form and/or timing includes an amplifying cavity. The amplification process is monitored in the amplifying cavity to obtain data about at least one property of the pulse sequence and/or the single pulse(s). The system also compares the obtained data with reference data and it controls at least one switching means for inputting, outputting and/or retaining the pulse(s) in the amplifying cavity such that at least one property of the pulse sequences and/or the pulses at an output of the laser system has substantially a specified value.

Abstract: In order to obtain a visually high quality image with excellent sharpness using a silver halide photosensitive material, it is necessary to reduce the ratio of EL light in the light output from a GaN based laser diode to 20% or less. For example, when the light intensity measured on a sheet of photosensitive paper is 0.05 mW, the thickness of a waveguide is 3 nm and the width of the waveguide is 3 ?m, this condition is satisfied with a length of a resonator being 1 mm or less. In other words, a waveguide width W1 and a resonator length L are set such that the product of the waveguide width W1 and the resonator length L (W1·L) becomes 0.003 mm2 or less. This reduces the output ratio of the EL light, and a high quality image with excellent sharpness can be obtained when a silver halide photosensitive material is exposed.

Abstract: A semiconductor laser device is one of AlGaInAs semiconductor laser devices, and has a multi-layer structure with a n-GaAs substrate on which a n-Al0.3Ga0.7As buffer layer, a n-Al0.47Ga0.53As clad layer, active layer portion, p-Al0.47Ga0.53As clad layer and p-GaAs cap layer are formed. The active layer portion is configured as a multi-layer structure including (Al0.37Ga0.63)0.97In0.03As light guide layer, Al0.1Ga0.9As active layer and (Al0.37Ga0.63)0.97In0.03As light guide layer. By using the AlGaInAs layer to which In is added is used as the light guide layers, the active layer is under compressive strain. Accordingly, the lattice constant of the active layer at the laser emitting edge becomes smaller due to a force from the adjacent light guide layers. The band gap energy of the active layer near the laser emitting edge becomes larger than the inside of laser device, thereby forming the window structure.

Abstract: When CW laser is irradiated on a semiconductor film while being relatively scanned in a fabrication process of a semiconductor device, many crystal grains extending in a scanning direction are formed. The semiconductor film irradiated in this way has characteristics substantially approximate to those of a single crystal in the scanning direction. However, because productivity and uniformity of laser annealing are low, mass-production is difficult. A plurality of laser beams is processed into linear beams and is allowed to possess mutually superposing portions to form a more elongated linear beam and to thus improve productivity. The linear beams the overlapping to one another have a positional relation satisfying a predetermined limitation formula, and uniformity of laser annealing can be remarkably improved.

Abstract: A vertical cavity surface emitting laser, including an active region, an electrical contact for injecting current into the active region in order to generate photons, and an aperture between the active region and the contact for restricting current flow into the active region. The aperture is sufficiently large in at least one transverse dimension for the active region to support multiple transverse modes, and the aperture and contact are configured to produce current crowding in the active region. The direction of photon emission from the laser is determined by the injection current selectively stimulating different transverse modes.

Abstract: In a conventional optical device which mounts a semiconductor light emitting element, the processing is difficult and a manufacturing process cost is expensive because of the necessity of forming via holes in a substrate. An optical device comprises a laser diode which needs heat radiation, a glass substrate which is integrally molded into a mold glass for arranging the laser diode, a metallic heat sink arranged at an edge of the glass substrate for radiating heat generated from the laser diode, wherein an active layer proximity surface of the laser diode is arranged to oppose the heat sink, both of them are connected with a conductive paste through a lateral groove formed in the glass substrate.

Abstract: A tuneable laser includes a gain section bounded at one end by a first reflector adapted to produce a comb of reflective peaks and on the other end by a second reflector in the form of a plurality of discrete grating units each capable of reflecting at one of the peaks of the comb, and each grating unit having at least two independently actuable electrodes, which when actuated independently one from the other is capable of reducing the reflectivity of the grating unit and in which at least two of the grating units have different pitches.

Abstract: A passively mode-locked solid-state laser is designed to emit a continuous-wave train (51, 52) of electromagnetic-radiation pulses, the fundamental repetition rate of the emitted pulses exceeding 1 GHz, without Q-switching instabilities. The laser includes an optical resonator (3.1), a solid-state laser gain element (2) placed inside the optical resonator (3.1), a device (1) for exciting said laser gain element (2) to emit electromagnetic radiation having the effective wavelength, and a device (4) for passive mode locking including a saturable absorber. The laser gain element (2) is a laser material with a stimulated emission cross section exceeding 0.8×10?18 cm2 at the effective wavelength, and is made of Nd:vanadate. The saturable absorber (4) is preferably a semiconductor saturable absorber mirror (SESAM) device. Even higher repetition rates are achieved by operating the laser in the soliton regime. For use in fiber-optical telecommunication, the laser wavelength is preferably shifted to 1.

Abstract: A laser diode that has a pluality of semiconductor epitaxial layers grown on a substrate. The diode includes a light generating layer located between two layers of n-type material. A thin layer of p-type material is interposed between the active layer and an n-type layer. The diode includes a layer of n-doped material located adjacent to a substrate. The laser diode further includes an active layer located between the n-doped layer and a layer of p-doped material. An additional layer of n-doped material is located between the p-doped material and a contact. The contact is biased so as to induce a recombination of holes and electrons in the active region and generate light. The light travels along the active layer, p-doped layer and in both n-doped layers. Having an n-doped layer between the contact and p-doped layer reduces the amount of photon absorption within the laser diode.

Abstract: A system for measuring the energy of an ultra-short pulse in a laser beam includes a half-wave plate for orienting the polarization of the beam. A polarizing beam splitter is used to reflect a portion of each pulse of the beam and a remainder of the beam is transmitted toward a target. Energy in the reflected portion is measured by a laser energy meter (“LEM”) to determine the energy in the remainder of the beam. An output signal from the LEM is used to obtain an error signal that can then be used to rotate the half-wave plate to control the energy level in the remainder of the beam. In an alternate embodiment, a fixed-ratio beam splitter and a second LEM are used to measure and control the energy in the remainder of the laser beam.