Abstract: In response to the output of an operational amplifier, a CPU sets via an R-D/A converter an R-constant current circuit for supplying a read power current Ir to a semiconductor laser thereby driving it, and also sets via a W0-D/A converter an W0-constant current circuit for supplying a first write power current Iw0 to the semiconductor laser thereby driving it. The output of the W0-D/A converter is applied to two voltage-controlled amplifiers so that W1-constant current circuit and W2-constant current circuit provide second and third write power currents Iw1 and Iw2, respectively, to the semiconductor laser in accordance with the outputs of the respective voltage-controlled amplifiers. The gains of these two voltage-controlled amplifiers are set by the CPU such that the gains corresponds to the ratios of Iw1 and Iw2 relative to Iw0.

Abstract: An improved lens structure is provided which reduces the scattering and/or reflection losses in an optical cavity. The lens comprising at least a first, second and third lens layer arranged vertically, the first and third lens layers being oxidized in first and third oxidized regions adjacent to first and third non-oxidized regions, the second layer disposed between the first and third layers and comprising a non-oxidized semiconductor material, the first and third non-oxidized regions comprising a semiconductor material, each of the oxidized regions having an aluminum contents greater than 20%; and appropriately spacing the first lens layer from the third lens layer to reduce the scattering and/or reflection losses in an optical cavity.

Abstract: This invention is a semiconductor device including a p-type InP substrate having a mesa stripe in which at least an active layer and an n-type cladding layer are formed, and a semiconductor layer so formed as to bury the side surfaces of the mesa stripe and having at least an n-type current blocking layer and a p-type current blocking layer, wherein the n-type current blocking layer contains approximately 8.times.10.sup.17 cm.sup.-3 or more of Se as an impurity and the n-type current blocking layer and the n-type cladding layer are not contacting each other.

Abstract: A semiconductor laser includes a ridge structure includes a cladding layer having a thermal expansion coefficient. Current blocking structures are disposed at both sides of the ridge structure and include Al.sub.x Ga.sub.1-x As first current blocking layers having an Al composition x larger than 0.7 and contacting the ridge structure. In this structure, even when the Al composition of the first current blocking layers is reduced at both sides of the ridge structure, the wavelength of light absorbed by the first current blocking layers does not exceed the wavelength of laser light produced in the active layer. Therefore, unwanted absorption of the laser light at both sides of the ridge structure is avoided, resulting in a semiconductor laser with improved laser characteristics.

Abstract: The object of the present invention is to realize a transparent waveguide path AlGaInP laser which is capable of a low threshold current and a high light output efficiency without deterioration in characteristic due to crystal distortion. The semiconductor laser comprises an active layer formed on a GaAs substrate, upper and lower clad layers containing the active layer therebetween a current block layer which transmits oscillation light and has a stripe-shaped opening is formed on the upper clad layer, an etching stopper layer formed between the upper clad layer and the current block layer and on the upper clad layer exposed in a stripe shape by the opening section of the current block layer, the etching stopper layer containing no aluminium; and a clad layer formed on the current block layer and on the etching stopper layer exposed in a stripe shape by the opening section of the current block layer, wherein the upper clad layer is formed of a semiconductor containing AlGaInP or AlInP.

Abstract: In a II-VI group semiconductor laser, on an n type GaAs substrate, an n type ZnSe layer, a multiquantum well layer of a ZnCdSe well layer and a ZnSe barrier layer, and a p type ZnSe layer are deposited in this order. A polycrystalline ZnO layer is provided on both sides of the p type ZnSe layer for constricting current. Multifilm reflecting mirrors, respectively constituted with a polycrystalline SiO.sub.2 layer and a polycrystalline TiO.sub.2 layer, for obtaining laser oscillation are provided on the p type ZnSe layer as well as on a surface of the n type ZnSe layer exposed by etching the GaAs substrate. Furthermore, a p type AuPd electrode and an n type AuGeNi electrode are respectively provided.

Abstract: A time delay device for an optical signal wherein an optical frequency comb is generated by a comb generation device. The optical frequency comb consists of a plurality of discrete and temporally spaced optical channels or carriers. The separation of the channels is dictated by the shifting frequency applied to the comb generation device and the temporal spacing is defined by the length of fiber used so that a time delay is created for each traverse of the fiber loop by the optical frequency comb. A filter connected to the comb generation device is used for tuning to a particular frequency or channel in the optical comb to obtain an optical signal having a desired time delay.

Abstract: A II-VI compound semiconductor laser diode includes a plurality of II-VI semiconductor layers forming a pn junction supported by a single crystal GaAs semiconductor substrate. The layers formed in the pn junction include a first cladding layer of a first conductivity type, a second cladding layer of a second conductivity type, and at least a first guiding layer between the first and second cladding layers. A quantum well active layer is positioned within the pn junction. Electrical energy is coupled to the laser diode by first and second electrodes. Various layers in the laser diode are formed using Be.

Abstract: A device for coupling optical fibers to a laser array comprises a flat plate (1) with a number of V-grooves (7) and a cover (2) with a number of V-shaped grooves (8), the plate (1) and the cover (2) being fitted and adjusted to each other in such a way that the grooves (7, 8) form channels with a rhombic cross section. In these channels of such a device, pointed optical waveguides (4) may be pushed to a stop (9, 10), and may then be automatically adjusted to a laser array (3) that may be arranged on the plate (1) or cover.

Abstract: A vertical-cavity surface-emitting laser component operating at a wavelength lying in the range 1.3 .mu.m to 1.55 .mu.m, the component comprising a layer of active material having an injection zone of width that is smaller than the width of the component, said zone emitting radiation when an electrical current is injected therein, the component also comprising an amplifying medium for amplifying the radiation and two mirrors that are reflective at the emission wavelength and disposed respectively above and below the amplifying medium. The amplifying medium includes a circular barrier extending facing the active material, said barrier opposing the passage of current and defining a current-passing channel in its center facing the injection zone, said channel being of a width that is smaller than the width of the injection zone.

Abstract: The present invention discloses a highly bright short wavelength light emitting semiconductor device with high reliance having improved crystallinity and surface smoothness. The device comprises at least one layer of In.sub.x Ga.sub.y Al.sub.1-x-y N (where, 0.ltoreq.x.ltoreq.1, 0.ltoreq.x+y.ltoreq.1) formed on a sapphire substrate or a Si substrate, wherein a ZnO buffer layer (2) which can lattice match In.sub.x Ga.sub.y Al.sub.1-x-y N is formed on the substrate (1) and a manufacturing method thereof.

Abstract: A variable power laser device includes a lasing medium having first and second end faces disposed parallel to one another, N side faces extending between the first and second end faces and a bevel face located at an intersection between the second end and one of the side faces, a first mirror separate from the first end face for directing a laser beam into the lasing medium so as to permit the laser beam to follow a helical transmission path defined by the N side faces, the transmission path being longer than the length of any of the N side faces, and a second mirror separate from the second end face for receiving an amplified laser beam output by the lasing medium and reflecting the amplified laser beam in a predetermined direction, wherein N is an integer greater than or equal to 3. The output power of the amplified laser beam is dependent on the number of loops in the transmission path.

Abstract: A VCSEL for emitting long wavelength light including a first mirror stack with mirror pairs in a GaAs/AlGaAs material system lattice matched to a GaTlP active region with an active structure sandwiched between a first cladding region adjacent the first mirror stack and a second cladding region, the active structure having a quantum well, and a second mirror stack lattice matched to the second cladding region and having mirror pairs in a GaAs/AlGaAs material system.

Abstract: An n type lower cladding layer, a quantum well structure active layer, a p type upper cladding layer, and a p type contact layer are epitaxially grown in this order on an n type GaAs substrate, and then a stripe-shaped SiN film extending in the laser resonator length direction and having a length not reaching the vicinity of a region that becomes a laser resonator facet is formed on the contact layer. An In film is formed on the SiN film and the contact layer and then heat treatment is performed, diffusing In to a depth reaching the lower cladding layer and disordering a part of the quantum well structure active layer. The active layer in the vicinity of the laser resonator facet is disordered by diffusing In at a temperature as low as 600.degree. C., and a window structure can be formed without diffusing a dopant impurity at a high temperature.

Abstract: A system comprises a substrate 4, an incident optical waveguide 5 formed on the substrate for receiving a light beam incident thereto, two phase-shift optical waveguides 6 formed on the substrate 4 to be branched from the incident optical waveguide 4 for varying a phase of a transmitted light beam in response to an electric field intensity, an outgoing optical waveguide 7 formed on the substrate 4 to join the phase-shift optical waveguides 6. At least one of the phase-shift optical waveguides 6 has a reversely polarized portion 8 reversely polarized. A light transmission film may be formed at one or a plurality of portions on the phase-shift optical waveguides 6. A buffer layer 14 may be formed on a part on or in the vicinity of the phase-shift optical waveguides 6. A transparent substance film for imparting a stress to one of the phase-shift optical waveguides 6 may be formed on a part or a whole of a portion without the buffer layer 14.

Abstract: A surface-emitting laser contains an optical cavity including a multiple quantum well (MQW) active region providing a source of optical emission in use. Top and bottom mirrors are disposed respectively above and below the MQW active region. The MQW active region is profiled so that it has a greater number of quantum wells in a central portion thereof than in a peripheral portion thereof. In alternative embodiments, a current-guiding region is profiled so that it has a first current-guiding portion with a relatively smaller aperture therethrough extending over a central portion of the MQW active region, and a second current-guiding portion with a relatively larger aperture therethrough; and one of the mirrors has a layer structure which, in a central portion of the cross-sectional area of such mirror, is different to that in a peripheral portion of said cross-sectional area.

Abstract: An vertical cavity surface emitting laser feedback system is provided which has a vertical cavity surface emitting laser for emitting a specific amount of optical radiation. A portion of the optical radiation is received by a detection means which is used to generate a feedback signal that corresponds to the amount of optical radiation being emitted by the vertical cavity surface emitting laser.

Abstract: An optical semiconductor device includes a plurality of quantum structures in an active layer thereof, wherein each of the quantum structures is confined in at least two of the three, mutually perpendicular dimensions, and wherein at least two of the quantum structures are separated with a distance that allows tunneling of carriers therebetween.

Abstract: A radiation-emitting semiconductor diode, especially a laser having a first and a second cladding layer, an active layer and a mesa which comprises at least the second cladding layer and which lies recessed in a third cladding layer. The second cladding layer comprises a first sub-layer which adjoins the active layer and is comparatively thin, and a second sub-layer which adjoins the first sub-layer and is comparatively thick, while the refractive index of the first sub-layer is lower than that of the second sub-layer. Confinement in the thickness direction of charge carriers and radiation is good in such a diode, while the third cladding layer has a relatively high refractive index (giving a relatively low bandgap). Thus, the third cladding layer has a relatively low aluminium content, while providing good lateral confinement.

Abstract: In general, the semiconductor laser device of the present invention comprises an emitting element comprising a doped diamond, which is doped with atoms of at least one rare earth metal and/or molecules of at least one compound containing a rare earth metal. The semiconductor laser device assembly according to the present invention comprises an emitting element of a doped diamond, which is a diamond doped with atoms of at least one rare earth metal and/or molecules of at least one compound containing a rare earth metal, and a thermal releasing element of a substantially undoped diamond, on which the semiconductor laser device are placed.