Coupled-cavity waveguide reflectors suitable for use in high-Q reflective spectral filters, narrow-linewidth lasers, and the like, are presented. Coupled-cavity waveguide reflectors in accordance with the present disclosure comprise multiple waveguide segments arranged in a series, each segment including a tooth having relatively higher refractive index and a gap having relatively lower refractive index, where the lengths of the teeth and gaps are based on the position of their respective segments in the series. The lengths of the teeth and gaps are selected such that the reflectivity of the segments align at only a single wavelength, thereby enabling very narrow-linewidth operation.

A semiconductor laser element includes: an n-type cladding layer disposed above an n-type semiconductor substrate (a chip-like substrate); an active layer disposed above the n-type cladding layer; and a p-type cladding layer disposed above the active layer, in which the active layer includes a well layer and a barrier layer, an energy band gap of the barrier layer is larger than an energy band gap of the n-type cladding layer, and a refractive index of the barrier layer is higher than a refractive index of the n-type cladding layer.

A Group-III nitride light emitting device that utilizes scattering of hot carriers generated by Auger recombination from an externally electrically-driven, relatively narrow band gap carrier generation region into a relatively wide band gap carrier recombination region, such that the relatively wide band gap carrier recombination region of the Group-III nitride light emitting device is internally electrically injected by the hot carriers generated in the externally electrically-injected relatively narrow band gap carrier generation region. The device is used for generation of incoherent light (a light-emitting diode) or coherent light (a laser diode).

A semiconductor laser device includes an N-type cladding layer, an active layer, and a P-type cladding layer. The active layer includes a well layer, a P-side first barrier layer above the well layer, and a P-side second barrier layer above the P-side first barrier layer. The P-side second barrier layer has an AI composition ratio higher than an AI composition ratio of the P-side first barrier layer. The P-side second barrier layer has band gap energy greater than band gap energy of the P-side first barrier layer. The semiconductor laser device has an end face window structure in which band gap energy of a portion of the well layer in a vicinity of an end face that emits the laser light is greater than band gap energy of a central portion of the well layer in a resonator length direction.

An embodiment semiconductor optical device includes an optical waveguide including a core, and an active layer extending in the waveguide direction of the optical waveguide for a predetermined distance and arranged in a state in which the active layer can be optically coupled to the core. The core and the active layer are arranged in contact with each other. The core is formed of a material with a refractive index of about 1.5 to 2.2, such as SiN, for example. In addition, the core is formed to a thickness at which a higher-order mode appears. The higher-order mode is an E.sub.12 mode, for example.

An optoelectronic device grown on a miscut of GaN, wherein the miscut comprises a semi-polar GaN crystal plane (of the GaN) miscut x degrees from an m-plane of the GaN and in a c-direction of the GaN, where −15<x<−1 and 1<x<15 degrees.

A Bragg grating includes a lower waveguide layer, a middle waveguide layer disposed on the lower waveguide layer, an upper waveguide structure disposed on the middle waveguide layer opposite to the lower waveguide layer, and a buried layer. The upper waveguide structure includes upper waveguide elements that are arranged on a surface of the middle waveguide layer, and that are spaced apart from one another by cavities. The buried layer fills the cavity. The middle waveguide layer has a refractive index lower than that of each of the lower waveguide layer and the upper waveguide elements. The lower waveguide layer has a doping type the same as that of the middle waveguide layer. A method for manufacturing the Bragg grating is also provided.

A semiconductor optical device includes a light emitting layer that emits light in a state of current injection; an optical waveguide in which a width or a thickness in an extending direction (y) of the light emitting layer varies along the extending direction; and a uniform diffraction grating having constant cycle, width and depth, wherein the light emitting layer, the optical waveguide and the uniform diffraction grating are arranged at positions where the light emitting layer, the optical waveguide, and the uniform diffraction grating are optically coupled to one another, the uniform diffraction grating is arranged above the light emitting layer, the optical waveguide is arranged below the light emitting layer, and the optical waveguide includes, in the extending direction, a first portion having a predetermined width, a second portion having a larger width than the width of the first portion, and a third portion having the same width as the width of the first portion.

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.

Some embodiments may include a laser diode having a strain-engineered cladding layer for optimized active region strain and improved laser diode performance. In one embodiment, the laser diode may include a semiconductor substrate having a material composition with a first lattice constant; and a plurality of epitaxy layers form on the semiconductor substrate, with plurality of epitaxy layers including a waveguide layer and cladding layers, wherein the waveguide layer includes an active region having a material composition associated with a target optical wavelength, wherein a second lattice constant of the material composition of the active region is different than the first lattice constant; wherein a material composition and/or thickness of an individual cladding layer of the cladding layers is/are arranged to impart a target stress field on the active region to optimize active region strain. Other embodiments may be disclosed and/or claimed.