Abstract: Examples disclosed herein relate to multi-wavelength semiconductor comb lasers. In some examples disclosed herein, a multi-wavelength semiconductor comb laser may include a waveguide included in an upper silicon layer of a silicon-on-insulator (SOI) substrate. The comb laser may include a quantum dot (QD) active gain region above the SOI substrate defining an active section in a laser cavity of the comb laser and a dispersion tuning section included in the laser cavity to tune total cavity dispersion of the comb laser.

Abstract: An ultraviolet light emitting element includes a light emitting layer, a cap layer, an electron barrier layer. The light emitting layer has a multi-quantum well structure including barrier layers each including a first AlGaN layer and well layers each including a second AlGaN layer. The electron barrier layer includes at least one first p-type AlGaN layer and at least one second p-type AlGaN layer. The cap layer is located between the first p-type AlGaN layer and one of the well layers closest to the first p-type AlGaN layer. The cap layer is a third AlGaN layer having an Al composition ratio greater than an Al composition ratio of each of the well layers and less than an Al composition ratio of the first p-type AlGaN layer. The cap layer has a thickness of greater than or equal to 1 nm and less than or equal to 7 nm.

Abstract: An edge emitting semiconductor laser chip includes a semiconductor body, which comprises at least one active zone in which electromagnetic radiation is generated during the operation of the semiconductor laser chip. At least one contact strip is arranged on a top surface at a top side of the semiconductor body. At least two delimiting structures are for delimiting the current spreading between the contact strip and the active zone. The delimiting structures are arranged on both sides of the contact strip.

Abstract: A disclosed vertical cavity surface emitting laser element includes a substrate, a laminated body sandwiching a semiconductor active layer with an upper reflecting mirror and a lower reflecting mirror, a lower electrode, and an upper electrode. The laser element emits laser light in a direction perpendicular to the surface of the substrate when an electric current is supplied between the upper electrode and the lower electrode. The laser element further includes a selective oxidation layer in the upper reflecting mirror having a current blocking structure made of an oxidized region and an unoxidized region, and a detectable portion formed on a side surface of a mesa structure shaped by the upper reflecting mirror including the selective oxidation layer and the active layer, thereby enabling detecting the position of the selective oxidation layer from a top of the laminated body in a depth direction of the laminated body.

Abstract: A VCSEL includes a grating layer configured with a non-periodic, sub-wavelength grating, in which the non-periodic, sub-wavelength grating includes at least one first section configured to have a relatively low reflection coefficient and at least one second section configured to have a relatively high reflection coefficient to cause light to be reflected in a predetermined, non-Gaussian, spatial mode across the sub-wavelength grating. The VCSEL also includes a reflective layer and a light emitting layer disposed between the grating layer and the reflector, in which the sub-wavelength grating and the reflector form a resonant cavity.

Abstract: A light emitting device includes first and second cladding layers and an active layer therebetween including first and second side surfaces and first and second gain regions, a second side reflectance is higher than a first side reflectance, a first end surface part of the first gain region overlaps a second end surface part of the second gain region in an overlapping plane, the first gain region obliquely extends from the first end surface to a third end surface, the second gain region obliquely extends from the second end surface to a fourth end surface, a first center line connecting the centers of the first and third end surfaces and a second center line connecting the centers of the second and fourth end surfaces intersect, and the overlapping plane is shifted from the intersection point toward the first side surface.

Abstract: A disclosed surface-emitting laser element includes a substrate, multiple semiconductor layers stacked on the substrate including a resonator structure including an active layer, a semiconductor multilayer mirror on the resonator structure, and a confined structure where a current passage region is enclosed by at least an oxide generated by oxidation of part of a selective oxidation layer containing aluminum, an electrode provided around an emission region, and a dielectric film provided in a peripheral portion within the emission region and outside a central portion of the emission region to make a reflectance of the peripheral portion lower than that of the central portion. The dielectric film is arranged such that a reflectance of a high-order transverse mode in a second direction is higher than that in a first direction, and a width of the current passage region in the first direction is greater than that in the second direction.

Abstract: A light emitting device includes first and second cladding layers and an active layer therebetween including first and second side surfaces and first and second gain regions, a second side reflectance is higher than a first side reflectance, a first end surface part of the first gain region overlaps a second end surface part of the second gain region in an overlapping plane, the first gain region obliquely extends from the first end surface to a third end surface, the second gain region obliquely extends from the second end surface to a fourth end surface, a first center line connecting the centers of the first and third end surfaces and a second center line connecting the centers of the second and fourth end surfaces intersect, and the overlapping plane is shifted from the intersection point toward the first side surface.

Abstract: A semiconductor laser apparatus includes, on a substrate, a first-conductivity type layer, an active layer, a second-conductivity type layer having a ridge extending along an optical waveguide direction, and a current blocking layer formed on sides of the ridge. The ridge is disposed to separate the substrate into a first region having a first width, and a second region having a second width greater than the first width, in a direction perpendicular to the optical waveguide direction. The second-conductivity type layer has a shock attenuating portion having a height greater than or equal to that of the ridge, on sides of the ridge. In the second region, a trench extending from an upper surface of the shock attenuating portion, penetrating at least the active layer, and reaching the first-conductivity type layer, is formed along the optical waveguide direction.

Abstract: A method for producing wide bandwidth laser emission responsive to high frequency electrical input signals, including the following steps: providing a heterojunction bipolar transistor device having collector, base, and emitter regions; providing at least one quantum size region in the base region, and enclosing at least a portion of the base region in an optical resonant cavity; coupling electrical signals, including the high frequency electrical input signals, with respect to the collector, base and emitter region, to cause laser emission from the transistor device; and reducing the operating beta of the transistor laser device to enhance the optical bandwidth of the laser emission in response to the high frequency electrical signals.

Abstract: A vertical cavity surface emitting laser diode (VCSEL) is disclosed, which reduces the light scattering by the step formed at the interface between the dielectric DBR and the semiconductor that reflects the mesa shape of the tunnel junction. The dielectric DBR of the invention includes a plurality of first films with relatively smaller refractive index and a plurality of second films with relatively larger refractive index. These first and second films are alternately stacked to each other to cause the periodic structure of the refractive indices. The VCSEL of the invention, different from the conventional device, provides the dielectric film with relatively larger refractive index that directly comes in contact with the semiconductor to set the node of the optical standing wave at the interface between the dielectric DBR and the semiconductor.

Abstract: A semiconductor laser apparatus includes, on a substrate, a first-conductivity type layer, an active layer, a second-conductivity type layer having a ridge extending along an optical waveguide direction, and a current blocking layer formed on sides of the ridge. The ridge is disposed to separate the substrate into a first region having a first width, and a second region having a second width greater than the first width, in a direction perpendicular to the optical waveguide direction. The second-conductivity type layer has a shock attenuating portion having a height greater than or equal to that of the ridge, on sides of the ridge. In the second region, a trench extending from an upper surface of the shock attenuating portion, penetrating at least the active layer, and reaching the first-conductivity type layer, is formed along the optical waveguide direction.

Abstract: Injection radiators are used for pumping solid-state and fiber lasers and amplifiers used for producing medical devices, laser production equipment, lasers generating a double-frequency radiation and in the form of highly efficient general-purpose solid-state radiation sources used in a given waveband, including white light emitters used for illumination. Said invention also relates to superpower highly-efficient and reliable injection surface-emitting lasers, which generate radiation in the form of a plurality of output beams and which are characterised by a novel original and efficient method for emitting the radiation through the external surfaces thereof.

Abstract: A separate-confinement heterostructure, edge-emitting semiconductor laser having a wide emitter width has elongated spaced apart intermixed and disordered zones extending through and alongside the emitter parallel to the emission direction of the emitter. The intermixed zones inhibit lasing of high order modes. This limits the slow axis divergence of a beam emitted by the laser.

Abstract: A semiconductor device includes a first nitride semiconductor layer formed on a substrate and a second nitride semiconductor layer formed on the first nitride semiconductor layer so as to be in contact with the first nitride semiconductor layer. The first nitride semiconductor layer contains a p-type impurity. The second nitride semiconductor layer contains an n-type impurity and a p-type impurity. In the second nitride semiconductor layer, the concentration of the n-type impurity is higher than the concentration of the p-type impurity.

Abstract: A method of bonding a compound semiconductor on a silicon waveguide is used for attaining a laser above a silicon substrate. While it is essential to attain laser oscillation by injection of a current, since amorphous is formed at the bonding surface of a silicon compound semiconductor, it is difficult to directly inject the current through the silicon waveguide to the compound semiconductor. Further, even when an electrode is formed near the waveguide and the current is injected, since the current is not injected near the silicon waveguide, laser oscillation through the silicon waveguide can not be attained. The problem is solved by forming a structure of laterally injecting a current to the silicon waveguide and concentrating the current near the silicon waveguide in a compound semiconductor.

Abstract: A surface emitting semiconductor laser device, having at least one monolithically integrated pump radiation source (20), in which the pump radiation source (20) has at least one edge emitting semiconductor structure (9) that is suitable for emission of electromagnetic radiation whose intensity profile transversely with respect to the emission direction (z) of the semiconductor structure follows a predeterminable curve. Such a surface emitting semiconductor laser device emits electromagnetic radiation having a particularly good beam quality.

Abstract: The present invention provides a VCSEL system comprising forming a first mirror, forming a vertical cavity on the first mirror, the vertical cavity including integrated multiple gain regions and forming a transverse p/n junction laterally to the integrated multiple gain regions, wherein forward biasing the transverse p/n junction causes photon emission in the integrated multiple gain regions.

Abstract: A two-wavelength semiconductor laser device includes a first conductive material substrate having thereon first and second regions separated from each other. A first semiconductor laser diode is formed on the first region. A non-active layer is formed on the second region and has the same layers as those of the first semiconductor laser diode. A second semiconductor laser diode is formed on the non-active layer. A lateral conductive region is formed at least between the first and second semiconductor laser diodes.

Abstract: Methods for producing surface-emitting semi-conductor lasers with tunable waveguiding are disclosed. The laser comprises an active zone containing a pn-transition, surrounded by a first n-doped semiconductor layer and at least one p-doped semiconductor layer. In addition to a tunnel junction on the p-side of the active zone, the tunnel junction borders a second n-doped semi-conductor layer with the exception of an area forming an aperture. An n-doped layer is provided between the layer provided for the tunnel junction and the at least one p-doped semiconductor layer. The tunnel junction may be arranged in a maximum or minimum of the vertical intensity distribution of the electric field strength. This enables surface-emitting laser diodes to be produced in high yields with stabilization of the lateral single-mode operation, high performance and wave guiding properties.

Abstract: In one aspect, a VCSEL includes a base region that has a vertical growth part laterally adjacent a first optical reflector and a lateral growth part that includes nitride semiconductor material vertically over at least a portion of the first optical reflector. An active region has at least one nitride semiconductor quantum well vertically over at least a portion of the lateral growth part of the base region and includes a first dopant of a first electrical conductivity type. A contact region includes a nitride semiconductor material laterally adjacent the active region and a second dopant of a second electrical conductivity type opposite the first electrical conductivity type. A second optical reflector is vertically over the active region and forms with the first optical reflector a vertical optical cavity overlapping at least a portion of the at least one quantum well of the active region. A method of fabricating a VCSEL also is described.

Abstract: GaAs(1?x)Sbx layers are grown by MOCVD. For lattice matching with InP, x is set to 0.5, while beneficial alternatives include setting x to 0.23, 0.3, and 0.4. During MOVCD, TMGa (or TEGa), TMSb, and AsH3 (or TBAs) are used to fabricate the GaAs(1?x )Sbx layer. Beneficially, the GaAs(1?x)Sbx layer's composition is controlled by the ratio of As to Sb. The MOCVD growth temperature is between 500° C. and 650° C. The GaAs(1?x)Sbx layer is beneficially doped using CCl4 or CBr4. A heavily doped GaAs(1?x)Sbx layer can be used to form a tunnel junction with n-doped layers of InP, AlInAs, or with lower bandgap materials such as AlInGaAs or InGaAsP. Such tunnel junctions are useful for producing long wavelength VCSELs.

Abstract: A method for producing controllable light pulses includes the following steps: providing a heterojunction bipolar transistor structure including collector, base, and emitter regions of semiconductor materials; providing an optical resonant cavity enclosing at least a portion of the transistor structure; and coupling electrical signals with respect to the collector, base, and emitter regions, to switch back and forth between a stimulated emission mode that produces output laser pulses and a spontaneous emission mode. In a form of the method, the electrical signals include an AC excitation signal, and part of each excitation signal cycle is operative to produce stimulated emission, and another part of each excitation signal cycle is operative to produce spontaneous emission.

Abstract: Semiconductor laser diodes, particularly high power AlGaAs-based ridge-waveguide laser diodes, are often used in opto-electronics as so-called pump laser diodes for fiber amplifiers in optical communication lines. To provide the desired high power output and stability of such a laser diode and avoid degradation during use, the present invention concerns an improved design of such a device, the improvement in particular significantly minimizing or avoiding (front) end section degradation of such a laser diode and significantly increasing long-term stability compared to prior art designs. This is achieved by establishing one or two “unpumped end sections” of the laser diode. One preferred way of providing such an unpumped end section at one of the laser facets (10, 12) is to insert an isolation layer (11, 13) of predetermined position, size, and shape between the laser diode's semiconductor material and the usually existing metallization (6).

Abstract: An apparatus and method for high speed phase modulation of optical beam with reduced optical loss. In one embodiment, an apparatus includes a first region of an optical waveguide disposed in semiconductor material. The first region has a first conductivity type. The apparatus also includes a second region of the optical waveguide disposed in the semiconductor material. The second region has a second conductivity type opposite to the first conductivity type. A first contact is included in the apparatus and is coupled to the optical waveguide at a first location in the first region outside an optical path of an optical beam to be directed through the optical waveguide. The apparatus also includes a first higher doped region included in the first region and coupled to the first contact at the first location to improve an electrical coupling between the first contact and the optical waveguide. The first higher doped region has a higher doping concentration than a doping concentration within the optical path.

Abstract: A VCSEL structure having thermal management. The structure may be designed for conveyance of heat from the active layer primarily through one of the mirrors to a material that removes heat externally away from the structure. Thermal management may involve various configurations of heat removal for various VCSEL structures. The structures may be designed to effect such respective configurations for heat removal.

Abstract: Alternative laser structures, which have potentially the same tuning performance as (S)SG-DBR and GCSR lasers, and a fabrication process which is similar to that of the (S)SG-DBR laser, are presented. The advantage of these structures is that the output power does not pass through a long passive region.

Abstract: The light-emitting device comprises a substrate, an active region and a tunnel junction structure. The substrate comprises gallium arsenide. The active region comprises an n-type spacing layer and a p-type spacing layer. The tunnel junction structure comprises a p-type tunnel junction layer adjacent the p-type spacing layer, an n-type tunnel junction layer and a tunnel junction between the p-type tunnel junction layer and the n-type tunnel junction layer. The p-type tunnel junction layer comprises a layer of a p-type first semiconductor material that includes gallium and arsenic. The n-type tunnel junction layer comprises a layer of an n-type second semiconductor material that includes indium, gallium and phosphorus. The high dopant concentration attainable in the second semiconductor material reduces the width of the depletion region at the tunnel junction and increases the electrostatic field across the tunnel junction, so that the reverse bias at which tunneling occurs is reduced.

Abstract: A device including an input port configured to receive an input signal is described. The device also includes an output port and a structure, which structure includes a tunneling junction connected with the input port and the output port. The tunneling junction is configured in a way (i) which provides electrons in a particular energy state within the structure, (ii) which produces surface plasmons in response to the input signal, (iii) which causes the structure to act as a waveguide for directing at least a portion of the surface plasmons along a predetermined path toward the output port such that the surface plasmons so directed interact with the electrons in a particular way, and (iv) which produces at the output port an output signal resulting from the particular interaction between the electrons and the surface plasmons.

Abstract: A surface emitting semiconductor laser device, having at least one monolithically integrated pump radiation source (20), in which the pump radiation source (20) has at least one edge emitting semiconductor structure (9) that is suitable for emission of electromagnetic radiation whose intensity profile transversely with respect to the emission direction (z) of the semiconductor structure follows a predeterminable curve. Such a surface emitting semiconductor laser device emits electromagnetic radiation having a particularly good beam quality.