Abstract: A method and apparatus are provided for stabilizing a distributed feedback semiconductor laser. The method includes the steps of comparing an optical output of a first oscillating mode of the semiconductor laser at a first polarization angle with an optical output of a second oscillating mode of the semiconductor laser at a second polarization angle orthogonal to the first polarization angle. A first feedback signal is provided to a cavity temperature controller of the semiconductor laser in response to detected differences of the compared first and second oscillating modes. The method further includes the step of comparing an output of the reference laser with an output of the semiconductor laser and providing a difference signal as a second feedback signal to the temperature controller of the semiconductor laser in response to detected differences between the reference laser and semiconductor laser.

Abstract: An array of annular waveguide VCSELs for achieving a stable single high order mode light source characterized as emitting a plurality of emission beams of varying wavelengths. The device array including a first mirror stack with mirror pairs in a Al.sub.x Ga.sub.1-x As/Al.sub.y Ga.sub.1-y As material system lattice matched to an active region. The active region includes an active structure sandwiched between a first cladding region adjacent the first mirror stack and a second cladding region, the active structure having at least one quantum well. The VCSEL further includes a second mirror stack lattice matched to the second cladding region and having mirror pairs in a Al.sub.x Ga.sub.1-x As/Al.sub.y Ga.sub.1-y As material system. The second mirror stack is etched to define a first VCSEL and at least one additional VCSEL, each VCSEL including an etched region, thereby defining an annular emission region through which light generated by the annular waveguide VCSEL is emitted.

Abstract: A semiconductor laser element which is composed of a compound semiconductor consisting of GaAs or the like, a silicon laser mount which is disposed beneath the semiconductor laser element so as to position the element, and on which an electrode layer as an electrode for the semiconductor laser element is formed, a heat sink which is disposed beneath the laser mount so as to dissipate, through the laser mount, the heat generated by the semiconductor laser element are mutually secured through hot contact bonding. The laser mount has a concave portion on the side opposite to its main surface on which the semiconductor layer element is secured, and the concave portion contains a heat dissipating body which is integrated thereinto and is made of copper having higher thermal conductivity than silicon.

Abstract: A semiconductor laser device of the present invention includes a substrate 201 made of n-type GaAs, an active layer 204, and a pair of cladding layers sandwiching the active layer 204. The device further includes a spacer layer 205 adjacent to the active layer 204 and a highly doped saturable absorbing layer 206. The carrier life time is shortened by doping the saturable absorbing layer 206 in a high concentration, whereby stable self-sustained pulsation can be obtained. As a result, a semiconductor laser device can be obtained, which has a low relative noise intensity in a wide range of temperatures.

Abstract: The invention provides a semiconductor light emitting device in which a light emitting layer is formed on a semiconductor substrate in a state of lattice mismatching with this semiconductor substrate, and by which light emission of high efficiency is obtained. A semiconductor material used as a base material of the light emitting layer is doped with impurities serving as radiative recombination centers. The semiconductor substrate is a GaP substrate and the semiconductor material as the base material of the light emitting layer is (Al.sub.x Ga.sub.1-x).sub.1-y In.sub.y P. This (Al.sub.x Ga.sub.1-x).sub.1-y In.sub.y P material is doped with nitrogen, oxygen, selenium, sulfur or tellurium as a first impurity for forming a donor level, and also with magnesium, zinc or cadmium as a second impurity for forming an acceptor level.

Abstract: A diode laser is disclosed that is self-pulsating without an increase in the starting current or a decrease in the efficiency. A special coating on an end face of the laser comprises in order a first mirror, a medium having an optical thickness which is at least substantially equal to an integer number of times half the wavelength of the generated electromagnetic radiation, and a second mirror. The coating comprises exclusively materials which have a higher bandgap value than that which corresponds to the wavelength of the generated radiation, while the reflectivities of the mirrors and the deviation of the optical thickness of the medium with respect to an integer number of times half the emission wavelength are chosen such that the group velocity dispersion (GVD) adjacent the wavelength of the generated electromagnetic radiation is negative, and preferably a minimum.

Abstract: In a semiconductor laser device including a multiple quantum well active layer formed by well layers and barrier layers alternately, and an n-type separate confinement heterostructured layer and a p-type separate confinement heterostructural layer sandwiching the multiple quantum well active layer, the n-type separated confinement heterostructured layer is thicker than the p-type separated confinement heterostructured layer.

Abstract: A semiconductor laser capable of controlling a polarization mode of output light is disclosed. In a fabrication method of the laser, after two laser portions are independently formed, the laser portions are positioned to be optically coupled to each other. In another fabrication method of the laser, after at least portions of two laser portions are separately formed, an irregularly-formed portion at a boundary portion therebetween is removed. The fabrication method can be facilitated and a degree of freedom in the polarization control can be increased, since the two laser portions are separately formed.

Abstract: The semiconductor laser disclosed includes a first conductivity type buffer layer, an active layer and a second conductivity type cladding layer which are sequentially positioned on a first conductivity type semiconductor substrate. The active layer has a laser gain region to which an electric current is injected. The laser gain region having a width varying linearly along a resonating direction is disposed between a high reflection film provided on a facet of a wide side of the laser gain region of the active layer and a low reflection film provided on a facet of a narrow side of the laser gain region of the active layer. The facet of the narrow side is for outputting oscillation beams of a high order mode. This provides a high electrical-to-optical conversion efficiency, and enables the outputting of a large output from a narrow light emission region.

Abstract: A structure consisting of a substrate and a gallium nitride based compound semiconductor formed on the substrate includes a light-emitting layer forming portion consisting at least of a semiconductor layer of a first conductivity type (an n-type cladding layer) and a semiconductor layer of a second conductivity type (a p-type cladding layer); a current blocking layer of the first conductivity type, which is formed within a semiconductor layer of the second conductivity type and in close proximity to the light-emitting layer forming portion, and a portion of which is removed in a region where a current flow, and electrodes connected to the semiconductor layer of the first conductivity type and the semiconductor layer of the second conductivity type, respectively.

Abstract: The invention is a semiconductor laser including a grating which is formed by regions of high impurity concentration surrounded by material having a lesser impurity concentration. The use of variations in doping concentration rather than different materials to provide reflection in the grating should simplify device fabrication.

Abstract: A semiconductor laser device of the present invention includes a substrate 201 made of n-type GaAs, an active layer 204, and a pair of cladding layers sandwiching the active layer 204. The device further includes a spacer layer 205 adjacent to the active layer 204 and a highly doped saturable absorbing layer 206. The carrier life time is shortened by doping the saturable absorbing layer 206 in a high concentration, whereby stable self-sustained pulsation can be obtained. As a result, a semiconductor laser device can be obtained, which has a low relative noise intensity in a wide range of temperatures.

Abstract: There is disclosed a compound semiconductor light-emitting device of gallium nitride series having high reliability, which can be operated by a low threshold current and a low operation voltage without deterioration. The device comprises a p-type semiconductor structure having high carrier concentration, which can easily form a low resistance p-side electrode, and which can uniformly implant carriers to an active layer highly efficiently. A p electrode contact layer having Mg added thereto is used as a p-type semiconductor layer. At least a Ga.sub.x2 In.sub.y2 Al.sub.z2 N (x2+y2+z2=1, 0.ltoreq.x2, z2.ltoreq.1, 0<y2.ltoreq.1) smoothing layer is formed on an active layer than the p-type contact layer. On a surface of the p-type contact layer, there is formed a layered structure having a Pt layer, and a Ti layer containing TiN, and a Ti layer in order. An alloy, formed of Pt-semiconductor, is formed between the p-type contact layer and the Pt layer.

Abstract: A semiconductor laser powered by both a dc current and an rf current. Varying the level of the dc current changes the shape, power and timing of a pulse emitted by the laser. The laser emits pulses in response to the leading or rising edge of the rf current. The time between the leading edge of the rf current and the emission of the pulse has been found to vary with the level of the dc current. Correspondingly, the shape and power of the emitted pulse also varies with the varying of the dc current. Further the shape, power and timing of the pulse varies with variations in the rf current. The present invention varies the dc and rf current to a laser, to vary the timing of the pulses from the rising edge, while maintaining the shape and power of the pulses substantially constant for all different variations in timing.

Abstract: A system for monitoring the amount of light emitted from a surface emitting laser includes a beam splitter which is fixed to the surface emitting laser and splits a part of a laser beam emitted from the laser as a monitor light, and a photodetector which detects the monitor light.

Abstract: A vertical cavity surface emitting laser includes a resonant cavity formed between a distributed Bragg reflector formed of semiconductor material and an overlying distributed Bragg reflector formed of dielectric material The resonant cavity contains a layer of laser active material sandwiched between spacer layers and a blocking layer which confines an energizing electric current to flow through the cavity between a metallic contact layer on the underside of the Bragg reflector and a contract. In order to support a preselected resonant mode, a series of concentric rings is formed in the blocking layer surrounding the resonant cavity so as to provide a Bragg structure which reflects light from the cavity with a phase characteristic that supports the preselected transverse resonant mode.

Abstract: A light amplifier device comprises an amplifier medium plate consisting of an upper part comprising two lateral faces (11) and (12) and a lower part comprising two lateral faces (13) and (14), the lateral faces (11) and (13) being located on a first face of the amplifier medium, the lateral faces (12) and (14) being located on a second face of the amplifier medium opposite said first face, at least two light beams (2) and (2') amplified by the amplifier medium and optical pumping means of said amplifier medium, wherein the light beam (2) is introduced into the amplifier medium at a lateral face (11) or (12) and the light beam (2') is introduced into the amplifier medium at a lateral face (13) or (14). The faces (11) and (12) are antiparallel to each other, the faces (13) and (14) being also antiparallel to each other. Application to power lasers.

Abstract: A monolithic laser structure has an infrared laser structure side by side with a red laser structure. The infrared and red laser structures share the same substrate and have the same material for the cladding layers and for the cap and barrier reduction layers. The red and infrared laser structures can have native oxide confined or metal confined ridge waveguides.

Abstract: A laser pump cavity apparatus with integral concentrator provides uniform gain and high absorption efficiency. The apparatus has a doped solid-state laser medium, a concentrator which has a top cladding layer formed on the top surface of the doped laser medium having a cylindrical focusing surface, a bottom cladding layer formed on the bottom surface of the doped laser crystal having a cylindrical focusing surface, and edge cladding layers formed on the side surfaces of the doped laser medium. Cold plates, each of which also preferably has one cylindrical surface of substantially identical shape, are placed in thermal contact with the cylindrical focusing surfaces of the top and bottom cladding layers to absorb heat. The cylindrical focusing surfaces preferably have hyperbolic or quasi-hyperbolic shape. The laser pump cavity apparatus is preferably edge-pumped with several laser diode arrays focused toward the line foci of the cylindrical focusing surfaces in directions transverse to a laser beam axis.

Abstract: A laser beam printer is provided which is capable of compensating for the difference in diameter between dots every colors and preventing unintentional coloring of the boundary between colors. In a conventional light source used for a printer, a spot diameter thereof is small upon low output and large upon high output. However, in a semiconductor laser device of the present invention, which is used for a light source for a printer, the spot diameter of the light source is controlled so as to be large upon low output and small upon high output. It is thus possible to keep the spot diameter of the laser light source constant. As a result, an irregular color-free laser beam printer can be materialized.