Abstract: A terahertz source implementing a {hacek over (C)}erenkov difference-frequency generation scheme in a quantum cascade laser. The laser includes an undoped or semi-insulating InP substrate with an exit facet that is polished at an angle between 10° to 40°. The laser further includes a first waveguide cladding layer(s) in contact with an active layer (arranged as a multiple quantum well structure) and a current extraction layer on top of the substrate. Furthermore, the laser includes a second waveguide cladding layer(s) on top of the active layer, where the first and second waveguide cladding layers are disposed to form a waveguide structure by which terahertz radiation generated in the active layer is guided inside the laser. The terahertz radiation is emitted into the substrate at a {hacek over (C)}erenkov angle relative to a direction of the nonlinear polarization wave in the active layer, and once in the substrate, propagates towards the exit facet.

Abstract: A terahertz source implementing a {hacek over (C)}erenkov difference-frequency generation scheme in a quantum cascade laser. The laser includes an undoped or semi-insulating InP substrate with an exit facet that is polished at an angle between 10° to 40°. The laser further includes a first waveguide cladding layer(s) in contact with an active layer (arranged as a multiple quantum well structure) and a current extraction layer on top of the substrate. Furthermore, the laser includes a second waveguide cladding layer(s) on top of the active layer, where the first and second waveguide cladding layers are disposed to form a waveguide structure by which terahertz radiation generated in the active layer is guided inside the laser. The terahertz radiation is emitted into the substrate at a {hacek over (C)}erenkov angle relative to a direction of the nonlinear polarization wave in the active layer, and once in the substrate, propagates towards the exit facet.

Abstract: The present invention relates to a surface-emitting laser diode with an active amplifying region (2) which is bounded by two laser mirrors (1, 3), while one or more polarization-selective layers (4) are provided for stabilizing the polarization in a region that is located on that side of at least one of the laser mirrors (1, 3) that is opposite the active amplifying region (2), these layers (4) extending parallel to the respective mirror (1; 3) and having a polarization-dependent refractive index and/or absorption.

Abstract: The present invention relates to a surface-emitting laser diode with an active amplifying region (2) which is bounded by two laser mirrors (1, 3), while one or more polarization-selective layers (4) are provided for stabilising the polarization in a region that is located on that side of at least one of the laser mirrors (1, 3) that is opposite the active amplifying region (2), these layers (4) extending parallel to the respective mirror (1; 3) and having a polarization-dependent refractive index and/or absorption.

Abstract: The present invention includes a vertical-cavity surface-emitting semiconductor laser diode having a resonator with a first distributed Bragg reflector, an active zone which has a p-n junction and is embedded into a semiconductor layer sequence, and a second distributed Bragg reflector. The semiconductor laser diode has an emission wavelength ?, wherein a periodic structure is arranged within the resonator as an optical grating made of semiconductive material and dielectric material, the main plane of extension of which is arranged substantially perpendicularly to the direction of emission of the semiconductor laser diode. The periodic structure is in direct contact with at least one of the semiconductor layers embedding the active zone and with at least one of the two distributed Bragg reflectors.

Abstract: The present invention includes a vertical-cavity surface-emitting semiconductor laser diode having a resonator with a first distributed Bragg reflector, an active zone which has a p-n junction and is embedded into a semiconductor layer sequence, and a second distributed Bragg reflector. The semiconductor laser diode has an emission wavelength ?, wherein a periodic structure is arranged within the resonator as an optical grating made of semiconductive material and dielectric material, the main plane of extension of which is arranged substantially perpendicularly to the direction of emission of the semiconductor laser diode. The periodic structure is in direct contact with at least one of the semiconductor layers embedding the active zone and with at least one of the two distributed Bragg reflectors.

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: The invention relates to a semiconductor laser of the surface emitting type. In order to provide a semiconductor laser which can be operated at normal ambient temperatures and has stable long-term characteristics, the semiconductor laser comprises an active zone having a pn transition, a first n-doped semiconductor layer on the n side of the active zone, a structured tunnel contact on the p side of the active zone, which forms a conductive transition to a second n-doped semiconductor layer on the p-side of the active zone, a structured dielectric mirror, which is applied to the second n-doped semiconductor layer, a contact layer, which forms a contact with the second n-doped semiconductor layer at the places where the dielectric mirror is not applied, and a diffusion barrier between the contact layer and the second n-doped semiconductor layer.

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: The invention relates to a semiconductor laser of the surface emitting type. In order to provide a semiconductor laser which can be operated at normal ambient temperatures and has stable long-term characteristics, the semiconductor laser comprises an active zone having a pn transition, a first n-doped semiconductor layer on the n side of the active zone, a structured tunnel contact on the p side of the active zone which forms a conductive transition to a second n-doped semiconductor layer on the p-side of the active zone, a structured dielectric mirror which is applied to the second n-doped semiconductor layer, a contact layer which forms a contact with the second n-doped semiconductor layer at the places where the dielectric mirror is not applied, and a diffusion barrier between the contact layer and the second n-doped semiconductor layer.

Abstract: Surface-emitting diode emission source (1) with an active layer (10) used to create optical emissions (101, 102, 103) that is located between a confinement layer (11) consisting of semi-conductor material of a conductivity type (n) and a confinement layer (12) consisting of semi-conductor material of a conductivity type (p) opposed to the first conductivity type (n), whereby an attenuation device (20) is present to suppress the emission components (103) spreading in direction (C) parallel to the layer plane (100) of the active layer (10). Advantage: Output of emission components spreading essentially perpendicular to the layer plane is improved.

Abstract: An optoelectric component has two waveguide layers and a layer with a periodic structure, which layers are arranged parallel to one another and are dimensioned so that a codirectional coupling is produced between modes guided in each of the waveguide layers. In order to prevent undesirable reflections, changes in the effective refractive index in the periodic structure is gradually changed along the direction of propagation. This change can be by the boundary of the periodic structure extending at an angle other than a right angle to the direction of propagation, either in a vertical or a lateral direction. The change can also be accomplished by a gradual change of the composition at the boundary of the periodic structure and adjacent portions or sections.

Abstract: Tunable laser diode having an integrated Mach-Zehnder interferometer is provided. A first and a second waveguide are arranged vertically relative to one another with respect to the layer plane as stripe-shaped layers. The second waveguide extends over the entire resonator length between mirror end faces, whereas the first waveguide is only present in one or more interconnected sections provided as coupling region. The waveguides are arranged in such close proximity to one another in this coupling region that coupling occurs between modes guided in the waveguides. An active layer and a tuning layer are arranged vertically relative to one another in these waveguides. A separate current injection into this tuning layer and into this active layer are present, and an interconnected section of the waveguide not present over the entire resonator length is a respective, natural multiple of the coupling length of two specific modes in the waveguides to be coupled.

Abstract: Tunable laser diode, whereby two waveguide lasers (5, 7) are arranged transversely relative to one another. A separate current injection into each of the two waveguide layers (5, 7) is possible due to an intermediate layer (6) situated between these waveguide layers (5, 7). An absorber layer (4) periodically interrupted in a longitudinal direction is arranged transversely relative to the layer plane, resulting in forward coupling with an imaginary degree of coupling.

Abstract: A tunable laser diode on a semi-insulating substrate having a stripe-shaped layer structure has an intermediate layer between an active layer and a tuning layer that is grown-over by an confinement layer that is doped for the same conductivity type as the intermediate layer. An oppositely doped, lateral region is electrically connected via an identically doped lower region to the active layer. An upper region is likewise oppositely doped and is electrically connected to the tuning layer. A contact layer is essentially planarly applied on the surface of the confinement layer and has respective portions on the appertaining regions on which the contacts provided with adequate bond areas are applied with a further contact layer for the common contact.

Abstract: A tunable semiconductor laser which is formed on a substrate 2 which has a first contact 14 on one surface and a third contact 16 on the opposite surface so as to supply the operating current which is laterally limited to a laser-active stripe through a barrier layer 4 l and including a second contact 15 on a ridge waveguide 11, 12, 13 so as to inject charge carriers into a tuning layer 9 mounted adjacent an active layer 6 and which is separated from the active layer by highly doped central layer 10 so as to allow tuning of the laser.

Abstract: In the manufacture of laser diodes having a stripe-shaped, active layer, a problem arises upon application of lateral layers, particularly of blocking pn-junctions for lateral current conduction, in that these layers are undesired above the active layer. By applying a protective cover layer that will dissolve in super-cooled melts of the material of the lateral layers, before the growth of the lateral layers, the growth of the lateral layers, particularly blocking pn-junctions, above the active stripe is avoided since the cover layer dissolves in the melt given epitaxial application of the lateral layers.

Abstract: A semiconductor laser arrangement is composed of two quasi-index guided laser diodes each with a light intensifying layer arranged in a plane shared by both diodes. The characteristics of the laser diodes are such that one polarization state predominates in one diode, while the other polarization state predominates in the other diode. Any desired degree of polarization dependency of the gain is set by the ratio of the operating currents of the two diodes, so that isotropic amplification can be achieved.

Abstract: An array of coupled waveguides in the form of MCRW laser diodes and/or passive waveguides are coupled to one another by optical waves of the TM-mode occurring in semiconductor regions between the waveguides that have a reduced thickness d, the neighboring waveguides being provided at a spacing a.

Abstract: An arrangement of two coupled laser diodes comprises first and second two-layer structures, each structure having a strip-shaped laser-active zone, and a middle layer. The first and second two-layer structures are symmetrically constructed relative to the middle layer at opposite sides thereof and directly across from each other so that the strip-shaped laser-active zones in each of the two-layer structures are positioned at a defined spacing directly across from each other and in symmetrical manner with respect to the middle layer. The middle layer is epitaxially deposited with a precisely dimensioned thickness relative to the two coupled laser diodes being employed.