A buried typed semiconductor optical device includes a semiconductor substrate having a pair of grooves extending in a first direction. An upper surface of a buried layer has a first region that is adjacent to a mesa stripe structure, overlaps with a corresponding one of the pair of grooves, is inclined so as to be higher in a second direction from the mesa stripe structure, and on which a passivation film is not formed. The upper surface of the buried layer has a second region that does not overlap with any of the pair of grooves, is flat, and is higher than a lower end of the first region, and on which the passivation film is formed. The upper surface of the buried layer has a connection region between the first region and the second region at a same height as the second region.

A semiconductor structure can comprise a plurality of first semiconductor layers comprising wide bandgap semiconductor layers, a narrow bandgap semiconductor layer, and a chirp layer between the plurality of first semiconductor layers and the narrow bandgap semiconductor layer. The values of overlap integrals between different electron wavefunctions in a conduction band of the chirp layer can be less than 0.05 for intersubband transition energies greater than 1.0 eV, and/or the values of overlaps between electron wavefunctions and barrier centers in a conduction band of the chirp layer can be less than 0.3 nm.sup.1, when the structure is biased at an operating potential. The chirp layer can comprise a short-period superlattice with alternating wide bandgap barrier layers and narrow bandgap well layers, wherein the thickness of the barrier layers, or the well layers, or the thickness of both the barrier and well layers changes throughout the chirp layer.

An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The optical semiconductor device is applied to a ridge-stripe type laser.

An electrically pumped photonic-crystal surface-emitting lasers with optical detector comprises plurality of air holes, by the variation of position and size proportion form a photonic crystal having main structure and sub structure, and produces an optical detection signal by light guiding proportion of the light guiding tunnel, further have power proportion of the laser by reading the strength of the optical detection signal, so the automatic power control circuit can feedback the power proportion for controlling the surface-emitting laser.

An optical device includes a gallium and nitrogen containing substrate comprising a surface region configured in a (20-2-1) orientation, a (30-3-1) orientation, or a (30-31) orientation, within +/10 degrees toward c-plane and/or a-plane from the orientation. Optical devices having quantum well regions overly the surface region are also disclosed.

A waveguide heterostructure for a semiconductor laser with an active part, comprising an active region layer depending of the type of semiconductor used, which is sandwiched between an electrode layer and a substrate, usable for dispersion compensation in a semiconductor laser frequency comb setup, an optical frequency comb setup and a manufacturing method.

A nitride semiconductor light-emitting element includes an n-type cladding layer including n-type AlGaN and having a first Al composition ratio, and a multiple quantum well layer in which a plurality (number N) of barrier layers including AlGaN having a second Al composition ratio more than the first Al composition ratio and a plural (number N) well layers having an Al composition ratio less than the second Al composition ratio are stacked alternately in this order, wherein the second Al composition ratio of the plurality of barrier layers of the multiple quantum well layer increases at a predetermined increase rate from an n-type cladding layer side toward an opposite side to the n-type cladding layer side.

Examples of the present disclosure include a tunable laser comprising a waveguide including gain section. The waveguide overlies and is optically coupled to another waveguide. The another waveguide has a reflector at one end. A laser cavity is formed in the waveguides.

A semiconductor laser diode is disclosed. In an embodiment a semiconductor laser diode includes a semiconductor layer sequence having at least one active layer and a ridge waveguide structure having a ridge extending in a longitudinal direction from a light output surface to a rear side surface and being delimited by ridge side surfaces in a lateral direction perpendicular to a longitudinal direction, wherein the ridge has a first region and a second region adjacent thereto in a vertical direction perpendicular to the longitudinal and lateral directions, wherein the ridge includes a first semiconductor material in the first region and at least one second semiconductor material different from the first semiconductor material in the second region, wherein the ridge has a first width in the first region, and wherein the ridge has a second width in the second region, the second width being larger than the first width.

A distributed feedback (DFB) laser outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The DFB laser includes a separate confinement heterostructure layer positioned between the quantum well active layer and then-type cladding layer. The DFB laser includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and then-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The DFB laser has a function to select a specific wavelength by returning a specific wavelength in the wavelength-variable laser.