Abstract: A semiconductor laser device has an n-type AlGaAs first cladding layer 2, a multiple quantum well active layer 3, and a p-type AlGaAs second cladding layer 4 formed in this order and supported by an n-type GaAs substrate 1. The multiple quantum well active layer 3 has two quantum well layers 3a and barrier layers 3b provided on both sides of each quantum well layer 3a. The quantum well layers 3a are each made of In1-v1Gav1As1-w1Pw1, while the barrier layers 3b are each made of In1-v2Gav2As1-w2Pw2. Here, v1 and v2 satisfy v1<v2, while w1 and w2 satisfy w1<w2. The barrier layers have a tensile strain with respect to the GaAs substrate, while the well layers have a compressive strain with respect to the GaAs substrate.

Abstract: A semiconductor laser element includes, on a substrate, at least a first conductive type first clad layer, an active layer, a second conductive type second clad layer, a current block layer having a stripe-shaped deficient portion extending in a direction of a resonator, a second conductive type third clad layer buried in the stripe-shaped deficient portion of the current block layer and a second conductive type protection layer provided on the third clad layer. The active layer includes at least a window region adjacent to its one end surface and an internal region having a quantum well structure, and a portion opposite to the internal region is irradiated with an ionized atom from a surface of a layer arranged on the second conductive type second clad layer side and thereafter subjected to heat treatment to form the window region.

Abstract: In a semiconductor laser device having a quantum well active layer, an undoped thin spacer layer is formed between an undoped optical guide layer and a p-type cladding layer. The thickness of the spacer layer is preferably 5 nm or more but less than 10 nm. The spacer layer absorbs impurities diffusing thereinto from the p-type cladding layer. Thus, the dopant is prevented from being diffused into the undoped optical guide layer.

Abstract: A semiconductor laser device has an n-type AlGaAs first cladding layer 2, a multiple quantum well active layer 3, and a p-type AlGaAs second cladding layer 4 formed in this order and supported by an n-type GaAs substrate 1. The multiple quantum well active layer 3 has two quantum well layers 3a and barrier layers 3b provided on both sides of each quantum well layer 3a. The quantum well layers 3a are each made of In1−v1Gav1As1−w1Pw1, while the barrier layers 3b are each made of In1−v2Gav2As1−w2Pw2. Here, v1 and v2 satisfy v1<v2, while w1 and w2 satisfy w1<w2. The barrier layers have a tensile strain with respect to the GaAs substrate, while the well layers have a compressive strain with respect to the GaAs substrate.

Abstract: A semiconductor laser element includes, on a substrate, at least a first conductive type first clad layer, an active layer, a second conductive type second clad layer, a current block layer having a stripe-shaped deficient portion extending in a direction of a resonator, a second conductive type third clad layer buried in the stripe-shaped deficient portion of the current block layer and a second conductive type protection layer provided on the third clad layer. The active layer includes at least a window region adjacent to its one end surface and an internal region having a quantum well structure, and a portion opposite to the internal region is irradiated with an ionized atom from a surface of a layer arranged on the second conductive type second clad layer side and thereafter subjected to heat treatment to form the window region.

Abstract: A light emitting device includes: a plurality of n-type III-V group compound semiconductor layers; a plurality of p-type III-V group compound semiconductor layers; and an active layer. Carbon atoms and II-group element atoms are both added to at least one of the plurality of p-type III-V group compound semiconductor layers. Alternatively, carbon atoms and Si atoms are both added to at least one of the plurality of n-type III-V group compound semiconductor layers. Another semiconductor light emitting device has a current blocking structure formed on the double hetero (DH) junction structure, and the current blocking structure at least includes a two-layered n-type current blocking layers including a Se-doped n-type first current blocking layer provided closer to the DH junction structure and a Si-doped n-type second current blocking layer formed on the n-type first current blocking layer.

Abstract: The integrated optical control element of this invention includes: a first waveguide for allowing light incident from outside to propagate therein; a multilayer structure for allowing the light which has propagated in the first waveguide to be incident thereon and for transmitting the light therethrough or reflecting the light therefrom, the multilayer structure including at least one layer having a refractive index different from an equivalent refractive index of a region with which the at least one layer is in contact; and a second waveguide for receiving at least part of the light transmitted through or reflected from the multilayer structure.

Abstract: The integrated optical control element of this invention includes: a first waveguide for allowing light incident from outside to propagate therein; a multilayer structure for allowing the light which has propagated in the first waveguide to be incident thereon and for transmitting the light therethrough or reflecting the light therefrom, the multilayer structure including at least one layer having a refractive index different from an equivalent refractive index of a region with which the at least one layer is in contact; and a second waveguide for receiving at least part of the light transmitted through or reflected from the multilayer structure.

Abstract: A semiconductor laser device includes a substrate and a laminated structure formed on a top face of the substrate. The laminated structure includes (a) first and second guide layers and (b) a quantum well structure of compound semiconductor interposed between the first and second guide layers. The quantum well structure serves as a resonator of the device and includes at least one quantum well layer and at least one barrier layer. The quantum well layer has a thickness L.sub.z and the barrier layer has the energy gap larger than the energy gap of the quantum well layer so as to form a energy difference V.sub.0 between the bottom of the conduction band of the quantum well layer and the bottom of the conduction band of the barrier layer. The relationship represented by formula (I) is satisfied:L.sub.z .ltoreq.h / 2 (2m*V.sub.0).sup.1/2 (I)wherein h is Planck's constant and m* is the effective mass of electrons within the quantum well layer.

Abstract: A semiconductor laser device includes a substrate and a laminated structure formed on a top face of the substrate. The laminated structure includes (a) first and second guide layers and (b) a quantum well structure of compound semiconductor interposed between the first and second guide layers. The quantum well structure serves as a resonator of the device and includes at least one quantum well layer and at least one barrier layer. The quantum well layer has a thickness L.sub.z and the barrier layer has the energy gap larger than the energy gap of the quantum well layer so as to form a energy difference V.sub.O between the bottom of the conduction band of the quantum well layer and the bottom of the conduction band of the barrier layer. The relationship represented by formula (I) is satisfied:L.sub.z .ltoreq.h / 2 (2m.sup.* V.sub.O).sup.1/2 (I)wherein h is Planck's constant and m.sup.* is the effective mass of electrons within the quantum well layer.

Abstract: A semiconductor laser device includes a substrate and a laminated structure formed on a top face of the substrate. The laminated structure includes (a) first and second guide layers and (b) a quantum well structure of compound semiconductor interposed between the first and second guide layers. The quantum well structure serves as a resonator of the device and includes at least one quantum well layer and at least one barrier layer. The quantum well layer has a thickness L.sub.z and the barrier layer has the energy gap larger than the energy gap of the quantum well layer so as to form a energy difference V.sub.0 between the bottom of the conduction band of the quantum well layer and the bottom of the conduction band of the barrier layer. The relationship represented by formula (I) is satisfied:L.sub.z <h/2(2m*V.sub.0).sup.1/2 (I)wherein h is Planck's constant and m* is the effective mass of electrons within the quantum well layer.

Abstract: A semiconductor laser device of the present invention includes: a semiconductor substrate having a top face and a bottom face; a multi-layered structure formed on the top face of the semiconductor substrate, the multi-layered structure including an active layer; a stripe-shaped ridge portion which is formed on a first region of a top face of the multi-layered structure and which extends along a cavity length direction; a current blocking layer which covers both side faces of the ridge portion and a second region of the top face of the multi-layered structure; a first electrode formed at least on a top face of the ridge portion; and a second electrode formed on the bottom face of the semiconductor substrate, wherein the current blocking layer includes an insulating film and a resin film formed on the insulating film.

Abstract: A buried stripe type semiconductor laser device having a mesa stripe whose side faces are {111} facets and having a current confinement structure under epitaxial layers burying the mesa stripe is disclosed. The buried stripe type semiconductor laser device comprises a (100) semiconductor substrate having a stripe-shaped ridge in the <011> direction, a multi-layer film of a double hetero structure formed on the upper surface of the stripe-shaped ridge. The mutil-layer film includes a laser oscillating active layer of a smaller width than that of the stripe-shaped ridge. The current confinement means are formed at both sides of the mesa stripe on the semiconductor substrate. In addition, a method of fabricating a buried stripe type semiconductor laser device having no raised portion above a mesa stripe of a substrate is disclosed. The laser device can be mounted in position with the epitaxial layer side down, without the mesa stripe being damaged or strained.

Abstract: A periodic gain-type semiconductor laser device in which a mesa stripe has wide portions and narrow portions alternately arranged with a period that is an integral multiple of the half-wavelength of the emitted light. A multilayer structure including an n-AlGaAs first cladding layer 103 and an AlGaAs non-doped active layer 104 formed on the mesa stripe also have wide portions and narrow portions. An n-AlGaAs current confining layer 106 covers the sides of the AlGaAs non-doped active layer 104. The height of the top surface of the n-AlGaAs current confining layer 106 matches the height of the AlGaAs non-doped active layer 104. A p-AlGaAs second cladding layer 105 is formed on the AlGaAs non-doped active layer 104 and the current confining layer 106. A driving current is not injected into the narrow portions of the AlGaAs non-doped active layer 104.

Abstract: A semiconductor laser device having a mesa stripe whose side faces are facets of {111} planes is disclosed. In the laser device, a current blocking layer is formed on a semiconductor substrate whose main surface is a (100) plane, and a channel which is oriented along the <011> direction is formed in the current blocking layer. The mesa stripe is formed on the substrate within the channel by a selective growth technique. The mesa stripe has a multilayer structure including an active layer and is covered by a burying layer.

Abstract: A laminated structure of compound semiconductors comprising a IV semiconductor underlying substrate, a first III-V compound semiconductor layer that is formed as an intermediate layer on the IV compound semiconductor underlying substrate, and a second III-V compound semiconductor layer that is formed on the intermediate layer, wherein the thermal expansion coefficients of the IV compound semiconductor underlying substrate, E.sub.ts, the first III-V compound semiconductor layer, E.sub.t1, and the second III-V compound semicondductor layer, E.sub.t2, have the following relationship: E.sub.t1 >E.sub.t2 >E.sub.ts.