Abstract: A semiconductor laser, including: an n-type cladding layer that has n-type conductivity; an active layer formed on top of the n-type cladding layer; a p-type cladding base layer that is formed on top of the active layer and has p-type conductivity; a current-blocking layer that is formed on specified parts of an upper surface of the p-type cladding base layer and substantially has n-type conductivity; and a p-type buried cladding layer that has p-type conductivity and is formed so as to cover the current-blocking layer and contact remaining parts of the upper surface of the p-type cladding base layer.

Abstract: An etching control layer with a composition different from that of a compound semiconductor substrate is deposited over the surface of the substrate. Then, a first multilayer structure, made up of multiple semiconductor layers including a first active layer with a composition different from that of the etching control layer, is defined over the etching control layer. A first semiconductor laser structure is formed out of the first multilayer structure on a first region of the substrate by selectively etching and patterning the first multilayer structure. A second multilayer structure, made up of multiple semiconductor layers including a second active layer, is defined over the surface of the substrate as well as over the first semiconductor laser structure. A second semiconductor laser structure is formed out of the second multilayer structure on a second region of the substrate by selectively etching and patterning the second multilayer structure.

Abstract: A semiconductor laser, includes: a first cladding layer; an active layer that is formed on top of the first cladding layer; a second cladding layer that is formed on top of the active layer and has a different type of conductivity to the first cladding layer; an etch-stop layer that is formed on top of the second cladding layer and has a same type of conductivity as the second cladding layer; and a light-confining construction that is formed on top of the etch-stop layer by an etching process. The etch-stop layer has a surface part that contacts the light-confining construction. This surface part is composed of an (AlxGa1−x)yIn1−yP semiconductor, where 0.2≦x<0.7 and 0<y≦1.

Abstract: A method for producing a semiconductor laser element includes steps of: forming a semiconductor layered structure on a first conductivity type semiconductor substrate, the semiconductor layered structure including a first conductivity type cladding layer, a quantum well active layer, and a first cladding layer of a second conductivity type; forming a diffusion control layer in a predetermined region on the semiconductor layered structure; forming a material layer which acts as an impurity source on the diffusion control layer; and diffusing impurities by a first thermal treatment from the material layer through the diffusion control layer into at least a part of the semiconductor layered structure including at least a part of the quantum well active layer, thereby forming an impurity diffusion region, wherein a part of the quantum well active layer in at least one cavity end face is disordered by diffusion of the impurities.

Abstract: A semiconductor laser has a first conduction-type cladding layer, an active layer, and a second conduction-type cladding layer formed on a first conduction-type semiconductor substrate. The second conduction-type cladding layer has a mesa-type stripe-shaped recessed portion in at least four spots, so as to form a central ridge portion, which constitutes a ridge-type current confinement portion, and two or more lateral ridge portions, which are positioned on both sides of the central ridge portion, have a height larger than to that of the central ridge portion, and include the second conduction-type cladding layer. An insulation film with a lower refractive index than the second conduction-type cladding layer is formed in a pair of stripes disposed respectively in the regions from the side surface of the second conduction-type cladding layer on both side surfaces of the central ridge portion toward the outside. The insulation film is not formed on the central ridge portion.

Abstract: An n-type GaAs buffer layer 702, an n-type AlGaInP cladding layer 703, a multiple quantum well active layer 704 made of AlGaInP and GaInP, a first p-type AlGaInP cladding layer 705a, an optical guide layer 707, a second p-type cladding layer 705b, a p-type GaInP saturable absorption layer 706, and a third p-type AlGaInP cladding layer 707 are sequentially formed on an n-type GaAs substrate 701. In this structure, the volume of the saturable absorption layer is reduced, and the optical guide layer is provided. As the volume of the saturable absorption layer becomes smaller, the more easily the carrier density can be increased, the more easily the saturated state can be attained, and the more remarkable the saturable absorption effect becomes. Thus, a semiconductor laser having stable self-oscillation characteristics and, as a result, having a low relative noise intensity is realized.

Abstract: The semiconductor laser of this invention includes an active layer formed in a c-axis direction, wherein the active layer is made of a hexagonal-system compound semiconductor, and anisotropic strain is generated in a c plane of the active layer.

Abstract: An n-type GaAs buffer layer 702, an n-type AlGaInP cladding layer 703, a multiple quantum well active layer 704 made of AlGaInP and GaInP, a first p-type AlGaInP cladding layer 705a, an optical guide layer 707, a second p-type cladding layer 705b, a p-type GaInP saturable absorption layer 706, and a third p-type AlGaInP cladding layer 707 are sequentially formed on an n-type GaAs substrate 701. In this structure, the volume of the saturable absorption layer is reduced, and the optical guide layer is provided. As the volume of the saturable absorption layer becomes smaller, the more easily the carrier density can be increased, the more easily the saturated state can be attained, and the more remarkable the saturable absorption effect becomes. Thus, a semiconductor laser having stable self-oscillation characteristics and, as a result, having a low relative noise intensity is realized.

Abstract: The semiconductor laser of this invention includes an active layer formed in a c-axis direction, wherein the active layer is made of a hexagonal-system compound semiconductor, and anisotropic strain is generated in a c plane of the active layer.

Abstract: An n-type GaAs buffer layer 702, an n-type AlGaInP cladding layer 703, a multiple quantum well active layer 704 made of AlGaInP and GaInP, a first p-type AlGaInP cladding layer 705a, an optical guide layer 707, a second p-type cladding layer 705b, a p-type GaInP saturable absorption layer 706, and a third p-type AlGaInP cladding layer 707 are sequentially formed on an n-type GaAs substrate 701. In this structure, the volume of the saturable absorption layer is reduced, and the optical guide layer is provided. As the volume of the saturable absorption layer becomes smaller, the more easily the carrier density can be increased, the more easily the saturated state can be attained, and the more remarkable the saturable absorption effect becomes. Thus, a semiconductor laser having stable self-oscillation characteristics and, as a result, having a low relative noise intensity is realized.

Abstract: In a semiconductor laser including an active layer and a buried layer for absorbing laser light emitted from the active layer, an oscillation wavelength of the laser light is in a 650 nm band, an oscillation mode is a single transverse mode, and a peak of a light intensity distribution of the laser light is placed on the side opposite to the buried layer with respect to the center of the active layer.

Abstract: A semiconductor laser device of the present invention includes a substrate 201 made of n-type GaAs, an active layer 204, and a pair of cladding layers sandwiching the active layer 204. The device further includes a spacer layer 205 adjacent to the active layer 204 and a highly doped saturable absorbing layer 206. The carrier life time is shortened by doping the saturable absorbing layer 206 in a high concentration, whereby stable self-sustained pulsation can be obtained. As a result, a semiconductor laser device can be obtained, which has a low relative noise intensity in a wide range of temperatures.

Abstract: A semiconductor laser device of the present invention includes a substrate 201 made of n-type GaAs, an active layer 204, and a pair of cladding layers sandwiching the active layer 204. The device further includes a spacer layer 205 adjacent to the active layer 204 and a highly doped saturable absorbing layer 206. The carrier life time is shortened by doping the saturable absorbing layer 206 in a high concentration, whereby stable self-sustained pulsation can be obtained. As a result, a semiconductor laser device can be obtained, which has a low relative noise intensity in a wide range of temperatures.

Abstract: A semiconductor laser device of the present invention includes a substrate 201 made of n-type GaAs, an active layer 204, and a pair of cladding layers sandwiching the active layer 204. The device further includes a spacer layer 205 adjacent to the active layer 204 and a highly doped saturable absorbing layer 206. The carrier life time is shortened by doping the saturable absorbing layer 206 in a high concentration, whereby stable self-sustained pulsation can be obtained. As a result, a semiconductor laser device can be obtained, which has a low relative noise intensity in a wide range of temperatures.

Abstract: The semiconductor laser of this invention includes an active layer formed in a c-axis direction, wherein the active layer is made of a hexagonal-system compound semiconductor, and anisotropic strain is generated in a c plane of the active layer.