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 quantum well active layer is doped with 0.3 to 1×10.sup.18/cm.sup.3 of n-type impurity.

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.

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.

A semiconductor laser device includes a first conductivity type cladding layer having a refractive index n.sub.c1, a first conductivity type side optical guide layer, an active layer, a second conductivity type side optical guide layer, and a second conductivity type cladding layer of n.sub.c2 laminated in order on a first conductivity type semiconductor substrate, wherein an oscillation wavelength is λ, a first conductivity type low refractive index layer of n.sub.1 lower than n.sub.c1 having a thickness of d.sub.1 is provided between the first conductivity type side optical guide layer and the first conductivity type cladding layer, a second conductivity type low refractive index layer of n.sub.2 lower than n.sub.c2 having a thickness of d.sub.2 is provided between the second conductivity type side optical guide layer and the second conductivity type cladding layer, and a condition of a normalization frequency v.sub.2>v.sub.1 is satisfied.

A reflectivity of an end surface protective film of a semiconductor laser element is made less than or equal to 1% in a wide wavelength range. Semiconductor laser element includes semiconductor stack body having front end surface and rear end surface, and end surface protective film disposed on front end surface of semiconductor stack body. End surface protective film includes first dielectric layer disposed on front end surface and second dielectric layer stacked outside first dielectric layer. Second dielectric layer includes first layer stacked on first dielectric layer, second layer stacked on first layer, and third layer stacked on second layer. For wavelength λ, of a laser beam, refractive index n2 of second layer is higher than refractive index n1 of first layer and refractive index n3 of third layer, and a film thickness of second layer ranges from λ(8n2) to 3λ(4n2) inclusive.

A semiconductor laser element includes a ridge, and includes: a p-type first clad layer; and a p-type second clad layer arranged on the p-type first clad layer, the p-type first clad layer has a superlattice structure of an Al.sub.xGa.sub.1-xN layer and an Al.sub.yGa.sub.1-yN layer (0≤x≤y≤1), the p-type second clad layer includes Al.sub.zGa.sub.1-zN (0≤z≤y), the p-type first clad layer includes: a flat portion on which the p-type second clad layer is not arranged; and a protruding portion which protrudes upward from the flat portion and on which the p-type second clad layer is arranged, and the height of the protruding portion protruding from the flat portion is less than the thickness of the p-type first clad layer in the flat portion.

Semiconductor light emitting device includes semiconductor light emitting element and submount that includes mounting surface, semiconductor light emitting element includes: semiconductor multilayer structure that includes opposite surface opposite mounting surface and emission surface; and mounting electrode that is arranged on opposite surface and extends in a direction of emission of light, emission surface is located outside of an end portion of mounting surface, groove is formed in opposite surface of semiconductor multilayer structure to extend along mounting electrode in the direction of emission, and a first distance between emission surface and groove is greater than zero and less than a second distance between emission surface and mounting surface.

A light-emitting device that includes a substrate, and at least one column portion, wherein the column portion includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type different from the first conductivity type, and a light-emitting layer provided between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer is provided between the substrate and the light-emitting layer, the light-emitting layer includes a first well layer, and a barrier layer, the barrier layer includes a first layer provided between the first semiconductor layer and the first well layer, and the first layer has a cubic crystal structure.

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.

A semiconductor light-emitting device including a light-emitting layer, a first N-type waveguide layer and a plurality of semiconductor layers is provided. The light light-emitting layer has a first side and a second side opposite to the first side. The first N-type waveguide layer is disposed at the first side, and the semiconductor layers are disposed at the second side. The semiconductor layers include at least one P-type semiconductor layer and a plurality of N-type semiconductor layers, and a quantity of the N-type semiconductor layers is more than a quantity of the at least one P-type semiconductor layer.