Abstract: A novel method of producing a porous product is provided, including the steps of: preparing a molded product by subjecting a molding material comprising a polymer component and a pore-forming agent dispersed in the polymer component, the pore-forming agent assuming a solid state at a room temperature, to molding at a temperature which causes the pore-forming agent to melt; and soaking the molded product with a solvent which dissolves the pore-forming agent but fails to dissolve the polymer component, to form pores.

Abstract: An optical waveguide ridge 14 has a side with a flat portion 14a stretching uniformly from a top of the ridge to a surface of a semiconductor substrate 12, the flat portion 14a being in contact with an exposed surface of the substrate 12. A p-type electrode 22 is extended from the top of the optical waveguide ridge 14 downward while in close contact with a dielectric film 16 furnished on the flat portion 14a of the optical waveguide ridge 14. The p-type electrode 22 is further extended over the dielectric film 16 on to the exposed surface of the semiconductor substrate 12 where an end of the electrode 22 is formed into a bonding pad 22a.

Abstract: This invention relates to a method of producing a molded transparent covering member. The steps of the method comprise providing a silicon rubber material and a fluorescent substance together to form a material to be molded in a space between an inner surface of an upper mold and an outer surface of a lower mold; sand-blasting at least one of the inner surface of said upper mold and the outer surface of the lower mold; and injecting the material into the space formed between upper mold and the lower mold.

Abstract: A LED device which has an excellent color rendering property and no toxicity and does not bring about an increase in production cost more than necessary, and a covering member used for such a LED device can be provided.

Abstract: This invention relates to a transparent coating member mountable on a light-emitting diode including a fluorescent substance and a light diffusion substance including calcium carbonate in order to reduce color variation at various locations of a transparent coating member and also reduce manufacturing costs of the transparent coating member without significantly lower the level of chromaticity. Furthermore, this invention relates to a transparent coating member mountable on a light-emitting diode (LED) including a fluorescent substance and a light storing pigment. This structure allows an exhibition of afterglow of the transparent coating member after turning off the light in a room so that locating the position of the transparent coating member is made easier thereafter. The light diffusion substance and the light storing pigment can be added to the transparent coating member to acquire both advantages derived from respective substances.

Abstract: A semiconductor laser diode includes a mesa having a width on a semiconductor substrate and aligned with a direction of resonance, a current blocking layer formed by selective growth on both sides of the mesa and having a first embedded layer and a second embedded layer covering the first embedded layer.

Abstract: A semiconductor optical device includes a semiconductor laser region for producing laser light and having a first optical waveguide mesa structure including a first active layer and a diffraction grating, and first current blocking layers adjacent to opposite sides; a light modulator region for modulating the laser light and having a second optical waveguide mesa structure continuous with the first optical waveguide mesa structure and including a second active layer, and second current blocking layers adjacent to opposite sides; and a window region for propagating the laser light modulated by the light modulator region and having a mesa-shaped window structure continuous with the second optical waveguide mesa structure, the mesa width of the window structure being larger than the mesa width of the second optical waveguide mesa structure. The light is prevented from leaking from the window and reaching the interface of the window structure and a burying layer adjacent to the window structure.

Abstract: A Mach-Zehnder modulator intensity modulating signal light using a simple drive circuit for the modulating voltage. The modulator includes two waveguides with respective multiple quantum well (MQW) structures. Well layers of the MQW structures of the two optical waveguides have different thicknesses or are made from different materials so the phase of light propagating through one waveguide advances and through the other waveguide is delayed in response to the same applied voltage. The phase-changed light signals are combined as an output light signal that is intensity modulated.

Abstract: A semiconductor optical modulator which, with a relatively simple configuration, eliminates phase modulation of output light from the semiconductor optical modulator by applying a voltage to a light absorption layer on the modulator. A nonlinear optical material layer changing refractive index is located in the direction of light propagation and cancels, in the output light, the phase modulation that is generated due to light intensity variations in the light absorption layer.

Abstract: A semiconductor laser device in which a semiconductor laser emitting laser light and a light modulator modulating the laser light are integrated on a compound semiconductor substrate, includes a hole trapping layer for suppressing a reactive current that is generated when the semiconductor laser is operated and that does not contribute to laser oscillation. The hole trapping layer has a first region in the semiconductor laser and a second region in the light modulator. The hole trapping layer has a high carrier concentration and a low resistance and is discontinuous between the semiconductor laser and the light modulator, so that isolation between the laser and the modulator is increased, whereby a high-frequency signal applied to the light modulator is prevented from flowing through the hole trapping layer into the laser.

Abstract: An optical semiconductor device includes a semiconductor laser diode having a first electrode for receiving a current for driving the laser diode, and a grounding electrode; a modulator for modulating light emitted from the semiconductor laser diode, the modulator having a second electrode for receiving a current for driving the modulator, and a grounding electrode connected to the grounding electrode of the semiconductor laser diode; a first resistor having a terminal connected to the first electrode of the laser diode; a second resistor connected between the second electrode of the modulator and the grounding electrode of the modulator; and a third resistor having a first terminal connected to the grounding electrode of the modulator and a grounded second terminal.

Abstract: A semiconductor laser includes an n type semiconductor substrate, an n type cladding layer, an active layer having an effective band gap energy, a p type cladding layer, and a tunnel diode structure including a high dopant concentration p type semiconductor layer and a high dopant concentration n type semiconductor layer having an effective band gap energy larger than the effective band gap energy of the active layer, a p side electrode disposed on the tunnel diode structure, and an n side electrode disposed on the rear surface of the n type semiconductor substrate. Since this semiconductor laser includes the tunnel diode structure disposed in the reverse bias direction with respect to the current flow direction, the contact resistivity of the ohmic contact of the p side electrode is lowered as compared to the case where the p side electrode is disposed on a p type semiconductor layer. The effective contact resistivity of the p side electrode is reduced.

Abstract: A semiconductor laser device includes an active layer from which laser light is emitted, a front facet reflection film, a back facet reflection film, and a resonator including the front and back facet reflection films, at least one of the front and back facet reflection films includes a saturable absorber to the laser light and, a thickness d of the facet reflection film comprising a saturable absorber is represented by ##EQU1## where n is a refractive index of the facet reflection film comprising a saturable absorber to a wavelength .lambda. of the laser light.

Abstract: A semiconductor laser comprises a first laser structure, a tunnel diode structure, and a second laser structure which are successively formed so that the forward directions of the first laser structure and the second laser structure are the same as the forward direction of the semiconductor laser, and the forward direction of the tunnel diode structure is reverse to the forward direction of the semiconductor laser, wherein laser beams are generated when a current flows in the forward direction, and an optical waveguide layer having a larger refractive index than the refractive indices of the first laser structure and the second laser structure and provided between the second laser structure and the tunnel diode structure or between the first laser structure and the tunnel diode structure.

Abstract: An optical semiconductor device includes an active layer through which light travels, having opposed first and second surfaces; a semiconductor layer of a first conductivity type disposed on the first surface of the active layer; a first electrode contacting the first conductivity type semiconductor layer; a semiconductor layer of a second conductivity type, opposite the first conductivity type, disposed on the second surface of the active layer; a second electrode contacting the second conductivity type semiconductor layer; a wire bonded to one of the first and second electrodes at a position in the resonator length direction corresponding to a localized maximum of a light density distribution in the active layer along the resonator length direction.

Abstract: A semiconductor laser device includes a semiconductor laser chip containing a diode having a polarity; a heat sink on which the semiconductor laser chip is mounted at an interface of the semiconductor laser chip and the heat sink, the heat sink including a pn junction generally parallel to the interface; and a block on which the heat sink is mounted, wherein the diode of the semiconductor laser chip and the pn junction are electrically connected in parallel and in opposite polarity so that the pn junction of the heat sink functions as a reverse current blocking diode for the semiconductor laser chip.

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 method is provided for the reduction of the level of dimethyl polysilioxane remaining in a silicone rubber product containing said dimethyl polysiloxane to an ultra-micro level, comprising the steps of immersing the silicone rubber product in an organic solvent for the dimethyl polysiloxane and subjecting the immersed product to ultrasonic vibrations in the organic solvent.