A semiconductor layer structure may include a substrate, a blocking layer disposed over the substrate, and one or more epitaxial layers disposed over the blocking layer. The blocking layer may have a thickness of between 50 nanometers (nm) and 4000 nm. The blocking layer may be configured to suppress defects from the substrate propagating to the one or more epitaxial layers. The one or more epitaxial layers may include a quantum-well layer that includes a quantum-well intermixing region formed using a high temperature treatment.

To provide a semiconductor optical device with device resistance reduced for optical communication. The semiconductor optical device includes an active layer (306) for emitting light through recombination of an electron and a hole; a diffraction grating (309) having a pitch defined in accordance with an output wavelength of the light emitted; a first semiconductor layer (311) including at least Al, made of In and group-V compound, and formed on the diffraction grating; and a second semiconductor layer (307) including Mg, made of In and group-V compound, and formed on the first semiconductor layer (311).

Methods are provided for modifying the emission wavelength of a semiconductor quantum well laser diode, e.g. by blue shifting the emission wavelength. The methods can be applied to a variety of semiconductor quantum well laser diodes, e.g. group III-V semiconductor quantum wells. The group III-V semiconductor can include AlSb, AlAs, Aln, AlP, BN, GaSb, GaAs, GaN, GaP, InSb, InAs, InN, and InP, and group III-V ternary semiconductors alloys such as Al.sub.xGa.sub.i.xAs. The methods can results in a blue shifting of about 20 meV to 350 meV, which can be used for example to make group III-V semiconductor quantum well laser diodes with an emission that is orange or yellow. Methods of making semiconductor quantum well laser diodes and semiconductor quantum well laser diodes made therefrom are also provided.

A process for preparing phosphoramidates of nucleosides where a desired enantiomer, having regard to the asymmetric chiral center of the phosphorus atom P, is provided in an enriched amount. The process comprises admixing a nucleoside with a phosphorochloridate in the presence of a catalyst comprising a metal salt selected from the group consisting of salts of Cu, Fe, La and Yb.

The light-emitting element of an embodiment outputs a clear optical image while suppressing light output efficiency reduction, and includes a substrate, a light-emitting unit, and a bonding layer. The light-emitting unit has a semiconductor stack, including a phase modulation layer, between first and second electrodes. The phase modulation layer has a base layer and modified refractive index regions, and includes a first region having a size including the second electrode, and a second region. Each gravity center of the second region's modified refractive index region is arranged by an array condition. The light from the stack is a single beam, and regarding a first distance from the substrate to the stack's front surface and a second distance from the substrate to the stack's back surface, a variation amount of the first distance along a direction on the substrate is smaller than a variation amount of the second distance.

A semiconductor laser may include a substrate, an active region, and an electron stopper layer. The electron stopper layer may include an aluminum gallium indium arsenide phosphide alloy. The aluminum gallium indium arsenide phosphide alloy may have an Al.sub.xGa.sub.yIn.sub.(1-x-y)As.sub.zP.sub.(1-z) composition.

A semiconductor light emitting device includes a substrate, and an array including three or more light emitting elements which are aligned above and along a main surface of a substrate and each emit light. The light emitting elements each include a clad layer of a first conductivity type, an active layer containing In, and a clad layer of a second conductivity type disposed above the substrate sequentially from the substrate. Among the light emitting elements, the compositional ratio of In in the active layer is smaller in the light emitting element located in a central area in an alignment direction than that in the light emitting elements located in both end areas in the alignment direction.

A semiconductor layer structure may include a substrate, a blocking layer disposed over the substrate, and one or more epitaxial layers disposed over the blocking layer. The blocking layer may have a thickness of between 50 nanometers (nm) and 4000 nm. The blocking layer may be configured to suppress defects from the substrate propagating to the one or more epitaxial layers. The one or more epitaxial layers may include a quantum-well layer that includes a quantum-well intermixing region formed using a high temperature treatment.

A reflector structure for a tunable laser and a tunable laser. A super structure grating is used as a reflector structure, and a suspended structure is formed around a region in which the super structure grating is located, to implement, using the suspended structure, thermal isolation around the region in which the super structure grating is located, and increase thermal resistance, such that less heat is lost, and heat is concentrated in the region in which the super structure grating is located, thereby improving thermal tuning efficiency of the reflector structure. Moreover, lateral support structures are disposed on two sides of the suspended structure, to provide a mechanical support for the suspended structure. In addition, regions in the super structure grating that correspond to any two lateral support structures on a same side of the suspended structure fall at different locations in a spatial period of the super structure grating.

A semiconductor laser device includes: a substrate having a main surface; a first cladding layer with a first conductive type and a second cladding layer with a second conductive type, which are stacked over the main surface of the substrate; and a light-emitting layer that is formed between the first cladding layer and the second cladding layer, and is formed on a first surface parallel to the main surface of the substrate; the light-emitting layer has a plurality of light-emitting regions emitting laser beams in a red range; and among the laser beams emitted from the light-emitting regions, the difference between a peak wavelength in an optical spectrum of at least one laser beam and a peak wavelength in an optical spectrum of the other laser beams is 1.5 nm or more.