Abstract: The present invention relates to an ink comprising: a solvent having a relative permittivity, measured at a frequency of 1 kHz and a temperature of 22° C., of 3 or less and a solubility in water at 25° C. of 20 mg/L or less; and a specific azo compound.

Abstract: The present invention relates to an ink comprising: a solvent having a relative permittivity, measured at a frequency of 1 kHz and a temperature of 22° C., of 3 or less and a solubility in water at 25° C. of 20 mg/L or less; and a specific azo compound.

Abstract: A semiconductor laser device includes: an electrically insulating film on the top face of a laser chip; and a metal film, on the electrically insulating film. The electrically insulating film and/or the metal film has, in plan, a polygonal shape with five or more apexes, each of the apexes having an interior angle less than 180 degrees. Stress due to a change of temperature during operation is reduced, resulting in a semiconductor laser device having a longer life and higher reliability.

Abstract: A ridge waveguide semiconductor laser includes an active layer, semiconductor layers on the active layer and having a ridge-shaped waveguide, an insulating film on the semiconductor layer, a first electrode layer in contact with the semiconductor layer through an opening in the insulating film, and a second electrode layer on the first electrode layer having a stripe shape and extending along the waveguide. A distance from an end face of a resonator of the laser to an edge of the second electrode layer does not exceed 20 ?m.

Abstract: A semiconductor laser device includes: an electrically insulating film, on the top face of a laser chip; and a metal film, on the electrically insulating film. The electrically insulating film and/or the metal film has, in plan, a polygonal shave with five or more apexes, each of the apexes having an interior angle less than 180 degrees. Stress due to a change of temperature during operation is reduced, resulting in a semiconductor laser device having a longer life and higher reliability.

Abstract: A ridge waveguide semiconductor laser includes an active layer, semiconductor layers on the active layer and having a ridge-shaped waveguide, an insulating film on the semiconductor layer, a first electrode layer in contact with the semiconductor layer through an opening in the insulating film, and a second electrode layer on the first electrode layer having a stripe shape and extending along the waveguide. A distance from an end face of a resonator of the laser to an edge of the second electrode layer does not exceed 20 &mgr;m.

Abstract: Disclosed herein is a semiconductor device for producing laser light from an active layer. The semiconductor device includes a ridge-shaped mesa including the active layer, current block layers formed so as to bury both sides of the mesa, a diffusion block layer formed on the mesa and the current block layers so as to be concatenated, and a p-InP clad layer formed on the diffusion block layer and containing a predetermined impurity. It is possible to restrain a reduction in the resistance of each current block layer due to the diffusion of the impurity of the p-InP clad layer into the current block layers and realize a high-speed operation of a laser with a modulator.

Abstract: A light modulator includes a semiconductor substrate having a main surface, a rear surface, and a grounding conductor on the rear surface. A wave guide section having a width is located on the semiconductor substrate. A bonding pad section on the semiconductor substrate is located adjacent to the wave guide section and an insulating layer covers the main surface of the semiconductor substrate. A portion of the insulating layer immediately opposite the bonding pad section includes a multiple layer structure of insulating films. An electrode opposite the bonding pad section is electrically connected to the wave guide section.

Abstract: A light modulator having a reduced parasitic static capacitance includes a semiconductor substrate having a mesa section and a bonding pad forming section formed thereon. A primary insulating film is formed on the substrate so as to continuously cover the mesa section and the bonding pad forming section. After a mask has been formed on a portion of the primary insulating film that is above the bonding pad forming section, the remaining portion of the primary insulating film is etched off, followed by removal of the mask. After the removal of the mask, a secondary insulating film is formed so as to continuously cover that portion of the primary insulating film above the bonding pad forming section and the mesa section so that a relatively thick insulating layer can be formed only above the bonding pad forming section.

Abstract: A light modulator having a reduced parasitic static capacitance includes a semiconductor substrate having a mesa section and a bonding pad section. A primary insulating film on the substrate continuously covers the mesa section and the bonding pad section. After a mask has been formed on a portion of the primary insulating film opposite the bonding pad section, the remaining portion of the primary insulating film is etched, followed by removal of the mask. After the removal of the mask, a second insulating film is formed continuously covering the primary insulating film opposite the bonding pad section and the mesa section so that a relatively thick insulating layer is present only opposite the bonding pad section.

Abstract: A semiconductor laser device includes a ridge waveguide having two side surfaces, a crystalline burying layer disposed at both side surfaces of the ridge waveguide, and a second conductivity type contact layer disposed on the burying layer and the ridge waveguide. The burying layer includes a first conductivity type first current blocking layer in contact with the side surfaces of the ridge waveguide, a second conductivity type second current blocking layer disposed on a portion of the first current blocking layer and separated from the ridge waveguide by a portion of the first current blocking layer near the ridge waveguide, a first conductivity type third current blocking layer disposed on a portion of the first current blocking layer near the ridge waveguide and on the second current blocking layer, and a second conductivity type final burying layer disposed on the third current blocking layer.

Abstract: In accordance with the invention, after a crystal growth is carried out successively to produce at least a first conductivity type lower cladding layer, an active layer, a second conductivity type first upper cladding layer of AlGaAs having an AlAs composition ratio of 0.38 to 0.6, an etching stopper layer of AlGaAs having an AlAs composition ratio of more than 0.6, and a second conductivity type second upper cladding layer of AlGaAs having an AlAs composition ratio of 0.38 to 0.6, the second upper cladding layer is selectively etched using an etchant including an organic acid and hydrogen peroxide, thereby forming a ridge. As a result, a ridge-type semiconductor laser device which has a desirable laser structure and an oscillation wavelength below 830 nm can be produced easily with improved controllability and reproducibility.

Abstract: In accordance with the invention, after a crystal growth is carried out successively to produce at least a first conductivity type lower cladding layer, and active layer, a second conductivity type first upper cladding layer of AlGaAs having an AlAs composition ratio of 0.38 to 0.6, an etching stopper layer of AlGaAs having an AlAs composition ratio of more than 0.6, and a second conductivity type second upper cladding layer of AlGaAs having an AlAs composition ratio of 0.38 to 0.6, the second upper cladding layer is selectively etched using an etchant including an organic acid and hydrogen peroxide, thereby forming a ridge. As a result, a ridge-type semiconductor laser device which has a desirable laser structure and an oscillation wavelength below 830 nm can be produced easily with improved controllability and reproducibility.

Abstract: A semiconductor laser includes a p type cladding layer and an n type cladding layer sandwiching an active layer serially disposed on a semiconductor substrate. The p type cladding layer includes a first dopant impurity producing p type conductivity and a smaller quantity of a second impurity that produces n type conductivity and ionically bonds to the first impurity. The first and second dopant impurities attract each other and cannot move individually during a crystal growth step at high temperature whereby the diffusion of those impurities into the active layer is suppressed, preventing formation of a deep impurity level in the active layer, resulting in a semiconductor laser with a reduced threshold current.

Abstract: A semiconductor laser device producing visible light includes a double heterojunction structure having a first conductivity type lower cladding layer, an active layer and a second conductivity type upper cladding layer, formed in a first epitaxial growth process of AlGaInP series materials and a contact layer formed in a second or later epitaxial growth process. The contact layer is In.sub.x GA.sub.1-x As.sub.y P.sub.1-y which can be grown at a lower temperature than used in the first process. Therefore, deterioration in laser characteristics due to the diffusion of dopant impurities during the growth of contact layer can be prevented, resulting in a semiconductor laser device having high performance and long lifetime.