Abstract: According to a semiconductor laser device of the present invention, the thickness and carrier concentration of a current blocking layer are set so as to cause a punch through on the current blocking layer when the semiconductor laser device is driven at a current which is one to ten times as large as a maximum rated value of a DC driving current. Both a light absorbing layer and a photocurrent blocking layer are formed between the current blocking layer and a second clad layer in order to prevent a light turn-on phenomenon from occurring. The light absorbing layer contacts the second clad layer and is constituted of a semiconductor crystal of a p-type conductivity type, which is undoped or has a low concentration. The photocurrent blocking layer contacts the current blocking layer and is constituted of a semiconductor crystal of the p-type conductivity type. If the band gaps of the light absorbing layer, photocurrent blocking layer, and active layer are represented by E.sub.ab, E.sub.ocb, and E.sub.

Abstract: A semiconductor laser device comprising, a first clad layer of the first conductivity type semiconductor crystal deposited on a first electrode layer, an active layer, a second clad layer formed of a semiconductor crystal of a second conductivity type, a current barrier layer having a stripe-like current inlet opening, a second electrode layer formed of a semiconductor crystal of the second conductivity type, and disposed on the current barrier layer and on the electric current inlet opening. A first electrode is formed on the second electrode layer. A second electrode is formed on the bottom surface of the first electrode layer. Between the current barrier layer and the second clad layer is formed a photoelectric current barrier layer formed of a semiconductor crystal of the first conductivity type having a larger band gap than that of the active layer.

Abstract: A light emitting diode comprises a semiconductor substrate of compound semiconductor, an active layer provided above the semiconductor substrate and including first and second active regions, the first active region being spaced apart from the second active region thereby controlling diffusion of an injected minority carrier in a radial direction, the first active region substantially operating as a light emitting region, and a window for emitting light generated at the first active region.

Abstract: In a method of manufacturing a semiconductor laser which includes a window structure at the periphery of an active layer. The width of the optical waveguide is determined by an etching, and the window structure is formed by an interdiffusion of atoms between a carrier confining layer and the active layer.

Abstract: In a semiconductor laser, a substrate is composed of a semiconductor basement and a semiconductor current-blocking layer on the basement. A straight channel is grooved into the current-blocking-layer to reach the basement. The straight channel has a constant width and is composed of a shallow window-region-channels in the vicinity of the cavity mirrors and a deep gain-region-channel in the middle of the laser cavity. A first cladding layer is grown on the substrate. A semiconductor active layer is grown on the first cladding layer. A second cladding layer is grown on the active layer. A semiconductor ohmic contact layer is grown on the second cladding layer. A pair of electrodes is deposited on each of the upper and lower surfaces of the semiconductor laser device. A pair of cleaved facets is faced toward the direction perpendicular to the channel.

Abstract: An inner stripe with self-aligned saturable-absorber structure semiconductor laser comprises a semiconductor substrate of a first conductivity type; a semiconductor current-blocking layer (CBL) of a second conductivity type formed on the substrate and having a stepped channel composed of an optical-guiding channel and current-restricting channel which is grooved at the bottom of the optical-guiding channel through the CBL into the substrate; a semiconductor cladding layer of a first conductivity type formed over the CBL to bury the stepped channel; a semiconductor active layer of a first or second conductivity type formed on the cladding layer; and a semiconductor cladding layer of a second conductivity type formed on the active layer, whereby laser noises can be markedly suppressed through wide temperature fluctuations and through the optical feedback range.

Abstract: A semicondcutor laser comprises a semiconductor base structure provided with an etched channel, and a plurality of semiconductor layers laminated on the base structure by a liquid-phase epitaxial growth method and performing a laser function. The base structure includes a GaAs substrate of one conductivity type, a layer formed on the substrate for preventing deformation of the channel, and an oxidation-preventing layer formed on the channel deformation-preventing layer. A current-blocking layer consisting of GaAs of the opposite conductivity type may be formed between the GaAs substrate and the channel deformation-preventing layer. Further, another layer for preventing the channel deformation may be provided between the GaAs substrate and the current-blocking layer. In the invented semiconductor laser, the semiconductor layers are epitaxially grown sufficiently on the base structure, and the channel deformation can be sufficiently suppressed.

Abstract: A novel spiro compound, 3,7,11,11-tetramethyl-spiro[5,5]-undeca-8-ene-1-one for altering the flavor or aroma of tobacco products. The spiro compound is prepared by reacting pulegone and piperylene in a solvent in the presence of a Lewis acid catalyst.

Abstract: 5-Acetyl-1,2,6-trimethyltricyclo[5,3,2,0.sup.2,7 ]dodeca-5-ene having the formula (I) ##SPC1##and a process for producing this compound. This compound is useful as a perfume.

Abstract: 1,2,6-Trimethyltricyclo[5,3,2,0.sup.2,7 ]dodeca-5-one having the formula (I) ##SPC1##and a process for producing this compound. This compound is useful as a perfume.

Abstract: 5,6-Epoxy-1,2,6-trimethyltricyclo[5,3,2,0.sup.2,7 ]dodecane having the formula (I) ##SPC1##and a process for producing this compound. This compound is useful as a perfume.

Abstract: 5-Acetyl-1,2,6-trimethyltricyclo[5,3,2,0.sup.2,7 ]dodeca-5-ene having the formula (I) v,2/14And a process for producing this compound. This compound is useful as a perfume.

Abstract: 1,2,6-Trimethyltricyclo[5,3,2,0.sup.2,7 ]dodeca-5-one having the formula (I) ##SPC1##and a process for producing this compound. This compound is useful as a perfume.