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: A semiconductor laser device, including a substrate; a ridge stripe formed on the substrate and including an active layer, an n-cladding layer and p-cladding layer, the n-cladding layer and the p-cladding layer interposing the active layer; in which the ridge stripe has a laser unit which lases. In one embodiment the ridge stripe has a tip portion having a tapered shape, and an angle formed inside the ridge stripe by a bottom surface of the ridge stripe and a side surface of the ridge stripe is in the range of about 60° and about 90°. In one embodiment, the laser device includes a misoriented substrate and the ridge stripe has current blocking layers formed on both sides thereof.

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 includes at least an active layer and a saturable absorbing layer, and a compressive strain amount in the saturable absorbing layer is set to be greater than a value of compressive strain in the active layer by about 0.3% or more. Alternatively, a semiconductor laser includes at least an active layer, a saturable absorbing layer, and a light guiding layer disposed in the vicinity of the saturable absorbing layer; and a compressive strain amount in the saturable absorbing layer is greater than a value of compressive strain in the active layer by about 0.3% or more.

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 light-emitting device with a double hetero structure, including: an active layer made of Ga.sub.1-x In.sub.x N (0.ltoreq.x.ltoreq.0.3) doped with a p-type impurity and an n-type impurity; and first and second cladding layers provided so as to sandwich the active layer.

Abstract: A semiconductor light-emitting device with a double hetero structure, including: an active layer made of Ga.sub.1-x In.sub.x N (0.ltoreq.x.ltoreq.0.3) doped with a p-type impurity and an n-type impurity; and first and second cladding layers provided so as to sandwich the active layer.

Abstract: An etching method for performing dry-etching on a III-V group compound semiconductor or a II-VI group compound semiconductor in a dry-etching apparatus comprising a plasma source for creating a plasma of density of about 10.sup.10 cm.sup.-3 or greater, using a mixed gas containing a gas including a halogen element and a gas including nitrogen. The etching conditions are as follows: (a flow rate of the gas containing said halogen gas)/(a flow rate of said nitrogen gas).gtoreq.1; and an internal pressure during etching reaction is about 1 mTorr or greater.

Abstract: In a semiconductor laser having an active layer and a cladding structure interposing the active layer, the cladding structure includes a saturable absorbing layer, and the saturable absorbing layer is formed of InGaAsP.

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 having an active layer, a pair of cladding layers interposing the active layer and a multi-quantum barrier provided between one of the pair of cladding layers and the active layer is provided, and the multi-quantum barrier includes barrier layers and well layers being alternated with each other. The semiconductor laser device also including an optical guide layer confining light generated in a quantum well layer, and the optical guide layer being undoped.

Abstract: A semiconductor laser according to the present invention includes: a semiconductor substrate; a multilayer structure provided on the semiconductor substrate, the multilayer structure including an active layer, a pair of cladding layers interposing the active layer, and current confining portion for injecting a current into a stripe-shaped predetermined region of the active layer, wherein the current confining portion includes a first current confining layer formed in regions excluding a region corresponding to the predetermined region of the active layer, the first current confining layer having an energy band gap larger than an energy band gap of the active layer and having a refractive index smaller than a refractive index of the active layer.

Abstract: An etching method for performing dry-etching on a III-V group compound semiconductor or a II-VI group compound semiconductor in a dry-etching apparatus comprising a plasma source for creating a plasma of density of about 10.sup.10 cm.sup.-3 or greater, using a mixed gas containing a gas including a halogen element and a gas including nitrogon. The etching conditions are as follows: (a flow rate of the gas containing said halogen gas)/(a flow rate of said nitrogen gas) .gtoreq.1; and an internal pressure during etching reaction is about 1 mTorr or greater.

Abstract: A semiconductor light-emitting device with a double hetero structure, including: an active layer made of Ga.sub.1-x In.sub.x N (0.ltoreq.x.ltoreq.0.3) doped with a p-type impurity and an n-type impurity; and first and second cladding layers provided so as to sandwich the active layer.

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: A semiconductor light-emitting device with a double hetero structure, including: an active layer made of Ga.sub.1-x In.sub.x N (0.ltoreq.x.ltoreq.0.3) doped with a p-type impurity and an n-type impurity; and first and second cladding layers provided so as to sandwich the active layer.