A nitride semiconductor laser device of one embodiment of the present disclosure includes a single-crystal substrate, a base layer, a sheet-shaped structure, a light emitting layer, and a resonator mirror. The single-crystal substrate extends in one direction. The base layer is provided on the single-crystal substrate and includes a nitride semiconductor. The sheet-shaped structure is provided on the base layer to stand in a direction perpendicular to the base layer. The sheet-shaped structure has an area of a side surface that is greater than an area of an upper surface. The side surface extends in a longitudinal direction of the single-crystal substrate. The sheet-shaped structure includes a nitride semiconductor. The light emitting layer is provided at least on the side surface of the sheet-shaped structure. The light emitting layer includes a nitride semiconductor. The resonator mirror is provided by a pair of end surfaces of the sheet-shaped structure that oppose each other in the longitudinal direction.

A laser device includes a substrate, a first waveguiding layer, an active layer, a second waveguiding layer, a contact layer, an insulating layer, a light-transmissive conducting layer, a first electrode, and a second electrode. The first waveguiding layer, the active layer, the second waveguiding layer, and the contact layer form an epitaxy structure having a first platform and a second platform. The first platform has multiple holes to form a photonic crystal structure. The insulating layer is over an upper surface and a sidewall surface of the first platform, and over an upper surface of the second platform. The sidewall surface passes through the contact layer, the second waveguiding layer, and the active layer. The light-transmissive conducting layer connects to the photonic crystal structure through an aperture of the insulating layer. The first electrode has an opening corresponding to the aperture. The second electrode is under the substrate.

In a semiconductor device, a quantum dot group includes a stack of plural quantum dot layers having different central wavelengths at which respective gains are maximum. A part of or all of the quantum dot layers are stacked so that the central wavelengths sequentially shifts along a stacking direction. The quantum dot group includes a longest wavelength layer group composed of some quantum dot layers including a longest wavelength layer having a longest central wavelength and at least one quantum dot layer stacked on the longest wavelength layer. The longest wavelength layer or the longest wavelength layer group has a larger gain at the central wavelength than the gain at the central wavelength of each of the other quantum dot layers.

An optoelectronic device, including: a laser source, including a semiconductor membrane, which rests on a first dielectric layer, and which is formed from a lateral segment doped n-type, a lateral segment doped p-type, and an optically active central segment located between and in contact with the doped lateral segments to form a lateral p-i-n junction lying parallel to the main plane. The semiconductor membrane is produced based on crystalline GaAs, the central segment includes GaAs-based quantum dots, and the doped lateral segments are produced based on AlxGa1-xAs with a proportion of aluminium x comprised between 0.05 and 0.30.

A method for etching a semiconductor structure (110) is provided, the semiconductor structure comprising a sub-surface quantum structure (30) of a first III-V semiconductor material,beneath a surface layer (31) of a second III-V semiconductor material having a charge carrier density of less than 5×10.sup.17 cm.sup.−3. The sub-surface quantum structure may comprise, for example, a quantum well, or a quantum wire, or a quantum dot. The method comprises the steps of exposing the surface layer to an electrolyte (130), and applying a potential difference between the first III-V semiconductor material and the electrolyte, to electrochemically etch the sub-surface quantum structure (30) to form a plurality of nanostructures, while the surface layer (31) is not etched. A semiconductor structure, uses thereof, and devices incorporating such semiconductor structures are further provided.

A photonic integrated circuit (PIC) includes a semiconductor substrate, one or more passive components, and one or more active components. The one or more passive components are fabricated on the semiconductor substrate, wherein the passive components are fabricated in a III-V type semiconductor layer. The one or more active components are fabricated on top of the one or more passive components, wherein optical signals are communicated between the one or more active components via the one or more passive components.

A semiconductor laser includes an active layer which emits laser light and cladding layers being formed so as to sandwich the active layer. The active layer includes a quantum dot layer including a plurality of quantum dots, which respectively confine movements of carriers in the three-dimensional directions. The laser radar device includes a light projection part which projects laser light and a light receiving part which receives reflected light of the laser light. The light projection part includes the semiconductor laser and a scanner which reflects the laser light, emitted from the semiconductor laser, to form a scanning laser light.

A device comprises first, second and third elements fabricated on a common substrate. The first element comprises an active waveguide structure supporting a first optical mode and at least one of the modal gain control structures. The second element comprises a passive waveguide structure supporting a second optical mode. The third element, at least partly butt-coupled to the first element, comprises an intermediate waveguide structure supporting intermediate optical modes. If the first optical mode differs from the second optical mode by more than a predetermined amount, a tapered waveguide structure in at least one of the second and third elements facilitate efficient adiabatic transformation between the second optical mode and one of the intermediate optical modes. No adiabatic transformation occurs between any of the intermediate optical modes and the first optical mode. Mutual alignments of the first, second and third elements are defined using lithographic alignment marks.

A nanowire can include a first semiconductor portion, a second portion including a quantum structure disposed on the first portion, and a second semiconductor portion disposed on the second portion opposite the first portion. The quantum structure can include one or more quantum core structures and a quantum core shell disposed about the one or more quantum core structures. The one or more quantum core structures can include one or more quantum disks, quantum arch-shaped forms, quantum wells, quantum dots within quantum wells or combinations thereof.

The present invention relates to a single photon source, comprising: a microcavity arranged between a concave first minor and a semiconductor heterostructure forming a planar second minor, wherein the microcavity supports an optical mode, a quantum dot embedded in the semiconductor heterostructure and facing the first minor, and a laser light source configured to provide laser light in the microcavity to excite the quantum dot to emit single photons exiting the microcavity.