An optical apparatus comprises a semiconductor substrate, and a supermode filtering waveguide (SFW) emitter disposed on the semiconductor substrate. The SFW emitter comprises a first optical waveguide, a spacer layer, and a second optical waveguide spaced apart from the first optical waveguide by the spacer layer. The second optical waveguide is evanescently coupled with the first optical waveguide and is configured, in conjunction with the first waveguide, to selectively propagate only a first mode of a plurality of optical modes. The SFW emitter further comprises an optically active region disposed in one of the first optical waveguide and the second optical waveguide.

There is provided a device to generate an output light. The device comprises a substrate, a quantum well structure (QWS) disposed on the substrate, and a waveguide disposed on the substrate and in contact with the QWS. The QWS has a first layer, a second layer, and a third layer. The second layer is disposed and quantum-confined between the first layer and the third layer. In addition, the second layer is to emit an input light when electrically biased. The input light has an optical field extending outside the QWS and into the waveguide, to optically couple the waveguide with the QWS. The waveguide is to provide an optical resonance cavity for the input light. Moreover, the waveguide has an optical outlet to transmit at least some of the input light out of the waveguide to generate the output light.

Visible spectrum quantum dot (QD) light emitting sources integrable with integrated silicon photonics include a plurality of epitaxially grown InP QDs within an active region. The light emitting sources include light emitting diodes (LEDs) and semiconductor lasers.

An optical apparatus comprises a semiconductor substrate and a slab-coupled optical waveguide (SCOW) emitter disposed on the semiconductor substrate. The SCOW emitter comprises an optical waveguide comprising: a first region doped with a first conductivity type; a second region doped with a different, second conductivity type; and an optically active region disposed between the first region and the second region. The optically active region comprises a plurality of quantum dots.

An optical apparatus comprises a semiconductor substrate, and a supermode filtering waveguide (SFW) emitter disposed on the semiconductor substrate. The SFW emitter comprises a first optical waveguide, a spacer layer, and a second optical waveguide spaced apart from the first optical waveguide by the spacer layer. The second optical waveguide is evanescently coupled with the first optical waveguide and is configured, in conjunction with the first waveguide, to selectively propagate only a first mode of a plurality of optical modes. The SFW emitter further comprises an optically active region disposed in one of the first optical waveguide and the second optical waveguide.

A semiconductor device having a GeSiSn base region combined with an emitter region and a collector region can be used to fabricate a bipolar transistor or a heterojunction bipolar transistor. The GeSiSn base region can be compositionally graded or latticed matched or strained to GaAs. The GeSiSn base region can be wafer bonded to a GaN or SiC collector region.

An optical semiconductor device includes an active layer having a plurality of quantum dot layers. The plurality of quantum dot layers includes at least one quantum dot player doped with a p-type impurity. Further, the plurality of quantum dot layers includes at least two quantum dot layers having different emission wavelengths and different p-type impurity concentrations.

A single-mode micro-laser based on a single whispering gallery mode optical microcavity and a preparation method thereof described includes: preparing a desired single whispering gallery mode optical microcavity doped with rare earth ions or containing a gain material such as quantum dots, wherein an optical microcavity configuration include a micro-disk cavity, a ring-shaped microcavity, and a racetrack-shaped microcavity; a material type include lithium niobate, silicon dioxide, silicon nitride, etc.; preparing an optical fiber cone or an optical waveguide of a required size which can excite high-order modes of the optical microcavity, such as a ridge waveguide and a circular waveguides; and coupling, integrating, and packaging the optical fiber cone or the optical waveguide with the microcavity. A pump light is coupled to the optical fiber cone or the optical waveguide to excite a compound mode with a polygonal configuration.

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.

An integrated optoelectronic device includes a substrate which supports a passive waveguide for index-confining, in two transverse directions, and guiding, along a longitudinal direction, at least one optical mode. The devices further include a first charge transport layer for transporting charge carriers of a first conductivity type, a second charge transport layer for transporting charge carriers of a second conductivity type, opposite to the first conductivity type, and an active layer comprising a particulate film of solution-processable semiconductor nanocrystals. The active layer is arranged relative to the charge transport layers to form a diode junction. The active layer and the first and the second charge transport layer are further formed on the substrate such that they each overlap at least a portion of the waveguide in a cross-section perpendicular to the longitudinal direction. The active layer is evanescently coupled to the waveguide.