Abstract: A device for the optical excitation of laser-active crystals with a diode laser (1) is disclosed. The diode laser (1) generates pump radiation (2), and the laser-active crystal (14) is arranged in a solid-state laser or solid-state laser amplifier. The laser-active crystal (14) has an axis (C) with strong absorption and an axis (A) with weak absorption. The pump radiation (2) from the diode laser (1) is substantially polarised linearly in a privileged polarisation direction. The device is configured in such a way that the pump radiation (2) is injected into the laser-active crystal (14) with a polarisation direction which is oriented parallel to the weak-absorption axis (A). The polarisation of the pump radiation in the vicinity of the laser-active crystal is oriented parallel relative to the weak-absorption axis.

Abstract: A semiconductor laser device includes a layer structure of a first conductive cladding layer, an active layer, and a second conductive cladding layer sequentially grown on a first conductive semiconductor substrate; and a light emitting facet from which a laser beam having a first wavelength is emitted. Refractive indexes of the first and the second conductive cladding layers with respect to the first wavelength are lower than an effective refractive index with respect to the first wavelength. With respect to a light having a second wavelength incident on the light emitting facet from outside, the refractive index of at least one of the first and the second conductive cladding layers is equal to or higher than the effective refractive index with respect to the second wavelength.

Abstract: A semiconductor laser apparatus capable of reducing a spread angle of emission light with downsizing has an active region between first and second end surfaces. A first reflection structure and a partial reflection structure are provided on the first end surface side. The end surface of the active region is divided into a total reflection region and a partial reflection region in combination with the first reflection structure and partial reflection structure. A laser resonator includes the first reflection structure and partial reflection structure. A second reflection structure is positioned on the way of a resonance optical path of the laser resonator. Light emitted within the active region propagates on a resonance optical path. An induction emission is produced. The semiconductor laser carries out a laser oscillation. Of the light arriving at the partial reflection structure, the portion transmitted through the partial reflection structure is outputted outside the apparatus.

Abstract: A method for manufacturing a semiconductor laser. As a preparative step for coating an end face of a resonator with a dielectric film, a cleavage plane of a semiconductor laminated structure that is to be the end face is subjected to a plasma cleaning to prevent a conductive film, which absorbs laser light, from attaching to the cleavage plane. During the plasma cleaning, a first process gas containing argon gas and nitrogen gas is introduced into a vacuumed ECR sputtering apparatus. After the cleavage plane is exposed to the first process gas in the plasma state for a certain time period without application of a voltage, a second process gas containing argon gas and oxygen gas is introduced, and the cleavage plane is exposed to the second process gas in the plasma state while a voltage is applied to the silicon target.

Abstract: Anti-reflective coatings may be used on laser high index gain media to mitigate reflection. An absentee layer may be used to compliment the antireflective coating to improve its antireflective performance over a broader range of wavelengths. The absentee layer comprises a material having a higher index of refraction than that of the gain media and has a thickness corresponding to multiple halfwave thicknesses related to the center wavelength output by the laser.

Abstract: A semiconductor laser device have, on a substrate, a semiconductor layer including an active layer sandwiched between an n-type layer and a p-type layer, the semiconductor layer having a sonator face formed by etching and a projection projecting out in an emission direction relatively to the resonator face, wherein a protective film is formed to extend from the resonator face to an end face of the projection, and, an emission critical angle, which is the largest angle at which light emitted from the resonator face can be radiated without being blocked by the projection and the protective film formed on the projection, is larger than an emission half-angle of an emission distribution in a vertical direction of a laser beam emitted from the resonator face.

Abstract: Provided are a semiconductor laser diode and a method of manufacturing the same. The semiconductor laser diode includes an n-type compound semiconductor layer; a resonant layer stacked on a predetermined region of the n-type compound semiconductor layer; a p-type compound semiconductor layer formed on the resonant layer; electrodes respectively formed on each of the p-type and n-type compound semiconductor layers; a bonding metal film stacked on the electrodes; and a high reflection film stacked on the other surface of the resonant layer facing a surface through which a laser generated from the resonant layer is emitted, wherein the thickness of the bonding metal film is greater than that of the high reflection film.

Abstract: A semiconductor laser device includes a semiconductor substrate on which a semiconductor thin film including an active layer is lamineted, a pair of electrodes respectively provided on opposite faces of the substrate, a light emitting surface defined on a side face of the substrate to which the active layer and an edge of at least one of the electrodes are exposed, and a protective film covering the light emitting surface. The protective film has a smaller thickness on the edge of the electrode than on the active layer. This arrangement makes it possible to suppress diffusion of an electrode material in the protective film and sufficiently protect the light emitting surface.

Abstract: A low reflective film is formed of, in sequence from a side in contact with a laser chip, a first dielectric film of a refractive index n1 and a thickness d1, a second dielectric film of a refractive index n2 and a thickness d2, a third dielectric film of a refractive index n3 and a thickness d3, and a fourth dielectric film of a refractive index n4 and a thickness d4, specifically, aluminum oxide Al2O3 with a refractive index n1=1.638 is used for the first dielectric film, silicon oxide SiO2 with a refractive index n2=n4=1.489 for the second and fourth dielectric films, tantalum oxide Ta2O5 with a refractive index n3=2.063 for the third dielectric film, respectively, resulting in a semiconductor laser device with a reflectance which is stably controllable.

Abstract: This invention provides a semiconductor laser that enables to oscillate at a wavelength defined by a Bragg grating formed therein in a wide temperature range without any temperature-controlling. The semiconductor laser comprises an active region and the Bragg grating formed with the active region. A light-emitting surface and a light-reflecting surface are formed so as to sandwiches the active region. The light-emitting surface has an anti-reflective coating, the reflectivity of which is so adjusted that the minimum thereof is at the wavelength where the gain attributed to the FP modes is the maximum and is smaller than 0.3%.

Abstract: A semiconductor laser element includes: a stack of layers having resonator facets; and at least one protection layer formed on at least one of the resonator facets. Each of the at least one protection layer includes at least first, second, and third sublayers. The first sublayer is formed nearest to the stack among the at least first, second, and third sublayers, and made of a material not containing oxygen (or nitrogen) as a constituent element. The second sublayer is made of an oxide (or nitride) produced by oxidizing (or nitriding) a portion of the first sublayer. The third sublayer is formed farthest from the stack among the at least first, second, and third sublayers, and made of an oxide (or nitride). The thickness d2 of the second sublayer and the total thickness d1 of the first and second sublayers satisfy a relationship, 0.1?d2/d1?0.9.

Abstract: A laser includes a narrow bandwidth AR coating for defining a frequency range for laser emission within the laser cavity. Advantageously, the narrow-band AR coating has a very low loss, which can be particularly useful if the gain medium has low gain. The narrow-band AR coating can be used to narrow the laser emission from a broadband gain medium (e.g. Cr:LiSAF), or to select from among discrete transition lines (e.g. Nd:YAG) without the use of cumbersome tuning elements. An etalon may be utilized to further narrow the fundamental wavelength, and the etalon may be substantially uncoated. For a solid state gain medium, the AR coating may be formed on one of the optical faces. A nonlinear element may be included for frequency-conversion, and the AR coating constrains the lasing frequency in the presence of this nonlinear loss and assists in maintaining single frequency operation to provide a stable frequency-converted output.

Abstract: A semiconductor laser includes semiconductor layers stacked on a substrate, and a pair of resonator end surfaces opposed to each other in the direction perpendicular to the stacking direction. In this semiconductor laser, a light emission side reflecting film is formed on one of the resonator end surfaces. A refractive index of the reflecting film against an emission wavelength of laser light is set to a value between an effective refractive index and a refractive index of the substrate. Another semiconductor laser includes a light emission function layer stack including a cladding layer and an active layer formed on one place of a translucent substrate; two electrodes having different polarities, which are provided on the light emission function layer stack side; and a light leakage preventive film formed on the other plane of the translucent substrate.

Abstract: A semiconductor laser device includes a dielectric multilayer film with a reflectance of 40% or more, on at least one of optical exit faces of a laser chip. The dielectric multilayer film includes a film of tantalum oxide (Ta2O5) and another film of a dielectric oxide, such as aluminum oxide (Al2O3), and silicon oxide (SiO2). The tantalum oxide film has an optical absorption coefficient smaller than that of silicon (Si) and thermal stability in emission superior to that of titanium oxide (TiO2), thereby remarkably improving the catastrophic optical damage degradation level of the laser chip.

Abstract: A semiconductor laser element that has window regions at its opposite end faces and an electrode portion superposed on an inner portion of the upper surface thereof to include covering an inner portion of the upper surfaces of the window regions without covering the entire upper surfaces of the window regions, by aligning a photomask for forming electrode pattern segments at a predetermined position over a laser substrate, which includes a plurality of element regions in a matrix pattern and a plurality of window region pattern stripes corresponding to the window regions of the element regions, the electrode pattern segments being used for forming electrodes at predetermined positions between the adjacent window region pattern stripes, wherein the photomask includes: an electrode pattern region for forming the electrode pattern segments; and an auxiliary mask having a scale section for measuring the amount of alignment deviation of the electrode pattern segments with respect to the window region pattern.

Abstract: An edge-emitting type 650 nm band red semiconductor laser device is provided, which includes a resonator structure having an active layer on a semiconductor substrate. A low reflection three-layer film is provided on an emitting edge face of the resonator structure and a high reflection multi-layer film is provided on a rear edge face of the resonator structure. The low reflection three-layer film is formed by sequentially stacking a first Al203 film having a thickness of 10 nm, a SiN4 film having a thickness of 190 nm, and a second Al203 film having a thickness of 10 nm on the emitting edge face by a sputtering process.

Abstract: Laser diodes containing aluminum at high concentration in an active layer have been usually suffered from remarkable facet deterioration along with laser driving operation and it has been difficult for the laser diodes to attain high reliability. An aluminum oxide film lacking in oxygen is formed adjacent to the semiconductor on an optical resonator facet, by which facet deterioration can be minimized and, accordingly, the laser diode can be operated with no facet deterioration at high temperature for long time and a laser diode of high reliability can be manufactured at a reduced cost.

Abstract: The present invention provides a highly reliable ridge-waveguide semiconductor laser diode and an optical module. The p-side electrode of the ridge-waveguide laser diode has a first conductor layer region and a second conductor layer region formed on the first conductor layer region. At least one of facets of the second conductor layer region is recessed inward from a reflection facet. Thus, the ridge-waveguide semiconductor laser diode has a structure in which strain which is caused by the electrode stress to be applied on the diode facet is reduced and the saturable absorption does not occur. The ridge-waveguide semiconductor laser diode thus obtained is highly reliable, and the optical module using the same is remarkably high in reliability.

Abstract: Systems and methods of passivating planar index-guided oxide vertical cavity surface emitting lasers (VCSELs) are described. These systems and methods address the unique susceptibility of these devices to damage that otherwise might be caused by moisture intrusion into the etch holes that are used to form the index-guiding confinement regions. In one aspect, a VCSEL includes a vertical stack structure having a substantially planar top surface. The vertical stack structure includes a top mirror, a bottom mirror, and a cavity region disposed between the top mirror and the bottom mirror and including an active light generation region. At least one of the top mirror and the bottom mirror has a layer with a peripheral region that is oxidized into an electrical insulator as a result of exposure to an oxidizing agent. The vertical stack structure defines two or more etched holes each extending from the substantially planar top surface to the oxidized peripheral region.