Abstract: Laser beams are synthesized by offsetting in different positions in the direction of the fast axis beam bundles radiated from semiconductor lasers, converging the optical axes of the beam bundles in the fast axis view, and introducing the beam bundles into an optical fiber after converging them in the directions of the fast and slow axes. A convergent angle transforming optical system is disposed further upstream of the upstream-most position in the positions where the optical axes of the beam bundles converged in the fast axis view intersect in the fast axis view. The whole beam bundle formed of the beam bundles converged in the fast axis view is passed through the convergent angle transforming optical system so that the angle of convergence of the whole beam bundle or part of the beam bundles is made smaller in the fast axis view, and introduced into the optical fiber.

Abstract: In a semiconductor laser device: a multilayer structure including a plurality of semiconductor layers is formed on a substrate; and at least one dielectric layer is formed on each of two end facets of the multilayer structure, where the at least one dielectric layer on each of the two end facets includes a reflectance control layer. In addition, at least one portion of the multilayer structure in at least one vicinity of at least one of the two end facets contains 10 to 1,500 times more oxygen than the other portions of the multilayer structure.

Abstract: In a method for producing a laser element, a brazing material is placed between a nitride-based semiconductor laser bar and a fixation surface of a heat sink, where the brazing material contains gold and one of tin and silicon as main components, the nitride-based semiconductor laser bar has at least three light-emission points formed on a substrate, the heat sink is made of copper or copper alloy, and the fixation surface has a predetermined shape. Then, the nitride-based semiconductor laser bar is fixed to the fixation surface of the heat sink by melting and solidifying the brazing material while pressing the nitride-based semiconductor laser bar toward the heat sink with a tool having a shape corresponding to the predetermined shape of the fixation surface.

Abstract: A laser apparatus includes: a block having a stepped shape formed with a plurality of mount portions which have different heights and are arranged in a first direction parallel to an optical axis in order of height; and a plurality of a collimator-lens array and a plurality of laser diodes, where the collimator-lens array in each of the plurality of sets is constituted by a plurality of collimator lenses which are arranged along a second direction and collimate laser beams emitted from the plurality of laser diodes in the set. The plurality of laser diodes and the collimator-lens array in each of the plurality of sets are fixed to one of the plurality of mount portions so that light-emission points of the plurality of laser diodes in the set are aligned in a third direction.

Abstract: In a laser apparatus, a plurality of semiconductor laser elements respectively emit laser beams; a multimode optical fiber has a light-entrance end and a light-emission end; an optical condensing system collects the laser beams emitted from the plurality of semiconductor laser elements, and couples the collected laser beams to the light-entrance end of the multimode optical fiber; and a protection member is arranged at the light-emission end of the multimode optical fiber, protects the light-emission end from the atmosphere, and has a light-emission window located at at least a predetermined distance from the light-emission end.

Abstract: A semiconductor laser device constituted by a stack of semiconductor layers formed on a substrate. The semiconductor layers include a first cladding layer of a first conductive type, an electric-to-optical conversion layer, and a second cladding layer of a second conductive type, formed in this order. In the semiconductor laser device, resonator surfaces are formed at opposite ends of the stack, and the end facet of the electric-to-optical conversion layer at each of at least one of the opposite ends of the stack protrudes outward from the shortest current path between the end facets of the first cladding layer and the second cladding layer at the end of the stack through semiconductor layers located between the first cladding layer and the second cladding layer.

Abstract: In a disclosed laser module, a usage amount of organic adhesive is set to no more than 1.0 g/ml. Thus, an equilibrium density of outgas components from the adhesive after an air removal treatment is less than 1000 ppm. In another laser module, a heat sink at which a semiconductor laser element is adhered on a submount, an electrode terminal wire-connected with the laser element, a photodiode wire-connected with the electrode terminal, and a zeolite adsorbent are fixedly provided on a stem. These are ring-welded in a container in a dry air atmosphere (80% nitrogen, 20% oxygen). In still another laser module, sixteen multiplexed lasers are disposed in a container. The container is connected with an air circulation apparatus, which is provided with a filter for removing contaminants, a rotary pump for circulating inert gas, and a valve for controlling replenishment of the gas.

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: In a semiconductor laser device: a multilayer structure including a plurality of semiconductor layers is formed on a substrate; and at least one dielectric layer is formed on each of two end facets of the multilayer structure, where the at least one dielectric layer on each of the two end facets includes a reflectance control layer. In addition, at least one portion of the multilayer structure in at least one vicinity of at least one of the two end facets contains 10 to 1,500 times more oxygen than the other portions of the multilayer structure.

Abstract: In a semiconductor laser device including a multilayered structure being formed of a plurality of semiconductor layers made of a plurality of group III-V compounds, and having a pair of opposite light-exit end facets; and a reflectance control layer being formed on at least one of the pair of light-exit end facets, and having at least two sublayers. In the semiconductor laser device, a region near a boundary between the multilayered structure and one of the at least two sublayers closest to the semiconductor layers of the reflectance control layer has an oxygen concentration of 15 atomic percent (atm %) or below.

Abstract: A semiconductor laser device constituted by a stack of semiconductor layers formed on a substrate. The semiconductor layers include a first cladding layer of a first conductive type, an electric-to-optical conversion layer, and a second cladding layer of a second conductive type, formed in this order. In the semiconductor laser device, resonator surfaces are formed at opposite ends of the stack, and the end facet of the electric-to-optical conversion layer at each of at least one of the opposite ends of the stack protrudes outward from the shortest current path between the end facets of the first cladding layer and the second cladding layer at the end of the stack through semiconductor layers located between the first cladding layer and the second cladding layer.

Abstract: An n-GaAs buffer layer, an n-AlGaAs lower cladding layer, an n- or i-InGaP lower optical waveguide layer, an InGaAsP quantum cell active layer, a p- or i-InGaP upper optical waveguide layer, a p-AlGaAs first upper cladding layer, a p- or i-InGaP etch-stopping layer, a p-AlGaAs second upper cladding layer, and a p-GaAs contact layer, are grown upon an n-GaAs substrate. A photoresist is coated on the wafer, and two grooves are formed by etching. Then, the photoresist on the perimeter of the device is removed and the contact layer is selectively etched. Next, the photoresist is lifted off. A Sio2 film is formed on the entire surface. After a window is formed in a portion of the SiO2 film corresponding to a ridge portion, a p-electrode is formed on a region of the Sio2 film other than the device perimeter.

Abstract: In a semiconductor laser element including a multilayered structure being formed of a plurality of semiconductor layers made of a plurality of group III-V compounds, and having at least a pair of cleaved end surfaces as a pair of light resonator surfaces, a first reflectance control layer, made of an oxygen gettering material which has a function of gettering oxygen, is formed on at least one of the pair of light resonator surfaces, and a second reflectance control layer made of a nitride of a group III material is formed on the first reflectance control layer.

Abstract: In a semiconductor laser device including a multilayered structure being formed of a plurality of semiconductor layers made of a plurality of group III-V compounds, and having a pair of opposite light-exit end facets; and a reflectance control layer being formed on at least one of the pair of light-exit end facets, and having at least two sublayers. In the semiconductor laser device, a region near a boundary between the multilayered structure and one of the at least two sublayers closest to the semiconductor layers of the reflectance control layer has an oxygen concentration of atomic percent (atm %) or below.

Abstract: A method for preparing a magnetic recording medium which comprises the steps:(a) providing on a non-magnetic support, a thin magnetic metal film,(b) providing on the thin magnetic film, a protective layer comprised substantially of carbon,(c) washing the surface of the protective layer at least once, each washing performed with one substance selected from the group consisting of an alkali detergent, a neutral detergent and an organic solvent, and(d) providing on the surface of the protective layer, a lubricating layer containing at least one organic lubricating agent.Where the magnetic recording mediums produced therefrom exhibit excellent lubricating properties and running durability and causes no attachments on a magnetic head. Magnetic disks produced from the magnetic recording mediums also exhibit excellent lubricating properties and running durability and also do not cause attachments on a magnetic head.

Abstract: A magnetic recording medium is disclosed, comprising a nonmagnetic support having thereon a magnetic layer, wherein at least one of ester compounds represented by formula (I) is present in or on the magnetic layer, ##STR1## wherein R.sub.1 represents a straight chain, saturated alkyl group having 6 to 12 carbon atoms, R.sub.2 represents a straight chain, saturated alkyl group having 4 to 10 carbon atoms, and R represents a branched or straight chain alkyl group having 4 to 22 carbon atoms.

Abstract: A perpendicular magnetic recording medium such as a floppy disk is created by providing on at least one surface of a non-magnetic support, a magnetic layer having perpendicular magnetic anisotropy and a protective layer by sputtering. First, a magnetic layer is provided, secondly, the magnetic layer is surface treated by a plasma treatment or by applying an oxide layer or a nitride layer thereon and thirdly, the protective layer is applied thereto.

Abstract: A method for producing a magnetic recording medium in which a flexible nonmagnetic support is moved continuously while being retained in contact with a plurality of spaced apart cylindrical cans to form thin films of metal on opposite sides of the support successively at portions where the support is in contact with the cylindrical cans. The tension of the support with respect to the Young's modulus thereof is adjusted to satisfy predetermined conditional expressions in each of a plurality of support conveyance sections which are defined by the spaced cylindrical cans.

Abstract: A method of preparing a magnetic recording medium in which a magnetic layer is deposited on a non-magnetic support and then a carbon protective layer is sputtered onto the magnetic layer. The sputtering is performed with a bias voltage of -10V to -100V being applied in the vicinity of the support and magnetic layer.

Abstract: Contaminant magnetic dust particles and flakes generated during the thin film coating of a substrate 9 in a vacuum chamber 1 are gravitationally collected in catch pans or troughs 8 disposed below the deposition zones. Magnets 10 are provided under the bottoms of the pans to enhance the attraction and retention of the particles. The contaminants may alternatively or additionally be removed directly from an upper surface of the substrate web by sandwiching one or more of its horizontal conveyance runs between a pair of magnets 22, 23, with the pole face area of the lower magnet being larger than that of the upper one.