Abstract: A semiconductor light emitting device includes a first-conductivity-type first multilayer film reflecting mirror, and a second-conductivity-type second multilayer film reflecting mirror; a cavity layer; and a first conductive section, a second conductive section, and a third conductive section. The cavity layer has a stacked configuration including a first-conductivity-type or undoped first cladding layer, an undoped first active layer, a second-conductivity-type or undoped second cladding layer, a second-conductivity-type first contact layer, a first-conductivity-type second contact layer, a first-conductivity-type or undoped third cladding layer, an undoped second active layer, and a second-conductivity-type or undoped fourth cladding layer.

Abstract: An ultrashort pulse/ultra-high power laser diode with a simple structure and configuration is provided. In a method of driving a laser diode, the laser diode is driven by a pulse current which is 10 or more times higher than a threshold current value. The width of the pulse current is preferably 10 nanoseconds or less, and the value of the pulse current is specifically 0.4 amperes or over.

Abstract: An ultrashort pulse/ultra-high power laser diode with a simple structure and configuration is provided. In a method of driving a laser diode, the laser diode is driven by a pulse current which is 10 or more times higher than a threshold current value. The width of the pulse current is preferably 10 nanoseconds or less, and the value of the pulse current is specifically 0.4 amperes or over.

Abstract: A semiconductor optical amplifier includes: a laminated structure sequentially including a first compound semiconductor layer composed of GaN compound semiconductor and having a first conductivity type, a third compound semiconductor layer having a light amplification region composed of GaN compound semiconductor, and a second compound semiconductor layer composed of GaN compound semiconductor and having a second conductivity type; a second electrode formed on the second compound semiconductor layer; and a first electrode electrically connected to the first compound semiconductor layer. The laminated structure has a ridge stripe structure. When widths of the ridge stripe structure in a light output end face and the ridge stripe structure in a light incident end face are respectively Wout, and Win, Wout>Win is satisfied. A carrier non-injection region is provided in an internal region of the laminated structure from the light output end face along an axis line of the semiconductor optical amplifier.

Abstract: Provided is an alignment method of a semiconductor optical amplifier with which optimization of coupling efficiency between incident laser light and light waveguide of the semiconductor optical amplifier is enabled without depending on an external monitoring device. The alignment method of a semiconductor optical amplifier is a method that optically amplifies laser light from a laser light source and outputs the optically amplified laser light, which adjusts relative position of the semiconductor optical amplifier with respect to the laser light entering into the semiconductor optical amplifier by flowing a given value of current to the semiconductor optical amplifier while entering the laser light from the laser light source to the semiconductor optical amplifier so that a voltage applied to the semiconductor optical amplifier becomes the maximum.

Abstract: A Vertical Cavity Surface Emitting Laser capable of decreasing the lowering of the yield due to displacement and separation of a pedestal without enormous increase of the threshold value and more difficult manufacturing process is provided. A base of a mesa spreads over the top face of a lower DBR layer. The base is a non-flat face in which end faces of a plurality of layers are exposed. The non-flat face is generated due to etching unevenness in forming the mesa, and is in a state of a step in which end faces of a low-refractive index layer and a high-refractive index layer included in the lower DBR layer are alternatively exposed. At least one of the layers exposed in the non-flat face in the plurality of low-refractive index layers included in the lower DBR layer is an oxidation inhibition layer.

Abstract: A method of driving an ultrashort pulse and ultrahigh power laser diode device having a simple composition and a simple structure is provided. In the method of driving a laser diode device, light is injected from a light injection means into a laser diode device driven by a pulse current having a value 10 or more times as large as a value of a threshold current.

Abstract: The present invention provides a semiconductor light receiving element capable of reducing capacity while minimizing increase in travel time of carriers. The semiconductor light receiving element includes a semiconductor stacked structure including a first conductivity type layer, a light absorbing layer, and a second conductivity type layer having a light incidence plane in order. The semiconductor light receiving element has an oxidation layer including a non-oxidation region and an oxidation region in a stacking in-plane direction in the light absorbing layer or between the first conductivity type layer and the light absorbing layer.

Abstract: The present invention provides a semiconductor device realizing improved adhesion between a low-dielectric-constant material and a semiconductor material. The semiconductor device includes, on a semiconductor layer, an adhesion layer and a low-dielectric-constant material layer in order from the semiconductor layer side. The adhesion layer has a projection/recess structure, and the low-dielectric-constant material layer is formed so as to bury gaps in the projection/recess structure.

Abstract: Provided is a driving method of a mode-locked semiconductor laser device comprising a laminated structure in which a first compound semiconductor layer, a third compound semiconductor layer having an emission region and a second compound semiconductor layer are successively laminated, a second electrode, and a first electrode. The laminated structure is formed on a compound semiconductor substrate having polarity, the third compound semiconductor layer includes a quantum well structure having a well layer and a barrier layer. The well layer has a depth of 1 nm or more and 10 nm or less. The barrier layer has an impurity doping density of 2×1018 cm?3 or more and 1×1020 cm?3 or less. An optical pulse is generated in the emission region by passing a current from the second electrode to the first electrode via the laminated structure.

Abstract: A semiconductor light emitting device includes a first-conductivity-type first multilayer film reflecting mirror, and a second-conductivity-type second multilayer film reflecting mirror; a cavity layer; and a first conductive section, a second conductive section, and a third conductive section. The cavity layer has a stacked configuration including a first-conductivity-type or undoped first cladding layer, an undoped first active layer, a second-conductivity-type or undoped second cladding layer, a second-conductivity-type first contact layer, a first-conductivity-type second contact layer, a first-conductivity-type or undoped third cladding layer, an undoped second active layer, and a second-conductivity-type or undoped fourth cladding layer.

Abstract: An ultrashort pulse/ultra-high power laser diode with a simple structure and configuration. The laser diode can be driven by a pulse current which is 10 or more times higher than a threshold current value. The width of the pulse current is preferably 10 nanoseconds or less, and the value of the pulse current is specifically 0.4 amperes or over.

Abstract: A semiconductor light emitting device includes a first-conductivity-type first multilayer film reflecting mirror, and a second-conductivity-type second multilayer film reflecting mirror; a cavity layer; and a first conductive section, a second conductive section, and a third conductive section. The cavity layer has a stacked configuration including a first-conductivity-type or undoped first cladding layer, an undoped first active layer, a second-conductivity-type or undoped second cladding layer, a second-conductivity-type first contact layer, a first-conductivity-type second contact layer, a first-conductivity-type or undoped third cladding layer, an undoped second active layer, and a second-conductivity-type or undoped fourth cladding layer.

Abstract: The present invention provides a semiconductor device realizing reduced occurrence of a defect such as a crack at the time of adhering elements to each other. The semiconductor device includes a first element and a second element adhered to each other. At least one of the first and second elements has a pressure relaxation layer on the side facing the other of the first and second elements, and the pressure relaxation layer includes a semiconductor part having a projection/recess part including a projection projected toward the other element, and a resin part filled in a recess in the projection/recess part.

Abstract: The present invention provides an optical device capable of suppressing a drive current and an optical output to be varied with a passage of the time. The optical device includes: an optical element including a first end face and a second end face, and emitting light having a wavelength from 300 nm to 600 nm both inclusive at least from the second end face in the first end face and the second end face; a pedestal including a supporting substrate supporting the optical element, and a connecting terminal electrically connected to the optical element; and a sealing section including a light transmitting window in each of a portion facing the first end face and a portion facing the second end face, and sealing the optical element.

Abstract: A laser diode with which separation of a current narrowing layer is able to be prevented is provided. The laser diode includes a mesa that has a first multilayer film reflector, an active layer, and a second multilayer film reflector in this order, and has a current narrowing layer for narrowing a current injected into the active layer and a buffer layer adjacent to the current narrowing layer. The current narrowing layer is formed by oxidizing a first oxidized layer containing Al. The buffer layer is formed by oxidizing a second oxidized layer whose material and a thickness are selected so that an oxidation rate is higher than that of the first multilayer film reflector and the second multilayer film reflector and is lower than that of the first oxidized layer. A thickness of the buffer layer is 10 nm or more.

Abstract: The present invention provides a semiconductor device realizing reduced occurrence of a defect such as a crack at the time of adhering elements to each other. The semiconductor device includes a first element and a second element adhered to each other. At least one of the first and second elements has a pressure relaxation layer on the side facing the other of the first and second elements, and the pressure relaxation layer includes a semiconductor part having a projection/recess part including a projection projected toward the other element, and a resin part filled in a recess in the projection/recess part.

Abstract: The present invention provides a laser diode realizing improved light detection precision. The laser diode includes a stack structure in which a first semiconductor layer of a first conduction type, an active layer, and a second semiconductor layer of a second conduction type are included in this order; a photodetection layer; and a plurality of light absorption layers provided on the corresponding position of antinodes or nodes of standing waves of light output from the active layer.

Abstract: A method of manufacturing a semiconductor light-emitting device includes steps of forming a vertical cavity structure including a layer to be oxidized on a semiconductor substrate, and then forming a circular groove having a depth which penetrates at least the layer to be oxidized from an upper surface of the vertical cavity structure, thereby forming a columnar mesa whose side face is surrounded by the groove, oxidizing the layer to be oxidized from the side face of the mesa, thereby forming a current confinement layer, and forming a mask layer covering at least a central region of the upper surface of the mesa and exposing at least an edge of the upper surface and the side face of the mesa to an external, and then etching at least the edge of the upper surface and the side face of the mesa by using the mask layer as a mask.

Abstract: An ultrashort pulse and ultrahigh power laser diode device capable of outputting pulse laser light having higher peak power with a simple composition and a simple structure is provided. The laser diode device includes: a laminated structure composed of a first compound semiconductor layer containing n-type impurity, an active layer having a quantum well structure, and a second compound semiconductor layer containing p-type impurity; a first electrode electrically connected to the first compound semiconductor layer; and a second electrode electrically connected to the second compound semiconductor layer, wherein the second compound semiconductor layer is provided with an electron barrier layer having a thickness of 1.5*10?8 m or more, and driving is made by a pulse current having a value 10 or more times as large as a threshold current value.