Abstract: A semiconductor laser device of this invention has a built-in passive guiding mechanism along the junction plane by growing planar double hetero (DH) layers on a grooved or projected substrate. It operates stably in the lowest transverse mode and provides light-output versus current characteristics fee of either kinks or any anomalies.

Abstract: In certain applications, it is desirable to have a semiconductor laser device having shorter wave lengths of oscillation than are possible with conventional semiconductor lasers. To accomplish this, a semiconductor laser device is formed having a double-hetero structure, which comprises a semiconductor substrate composed of a GaAsP crystal, a first cladding layer formed on the substrate and composed of a GaAlAsP crystal of one conducting type, an active layer formed on the first cladding layer and composed of GaInAsP crystal, and a second cladding layer formed on the active layer and composed of a GaAlAsP crystal of the conducting type reverse to that of the first cladding layer. The cladding layers disposed on both sides of the active layer have a lower refractivity and a larger band gap than the active layer.

Abstract: A semiconductor laser device has stabilized longitudinal and transverse modes without excess optical noise for a modulated signal generated by mode interaction. The fundamental construction of the semiconductor laser device comprises a structure wherein a first semiconductor layer is sandwiched between second and third semiconductor layers which have a greater band gap and lower index of refraction than the first semiconductor layer. That region of at least one of the second and third semiconductor layers which is remote from the first semiconductor layer corresponds substantially to a radiation region and serves as a light non-absorptive region in the shape of a stripe. A semiconductor layer has portions lying on both sides of the semiconductor layer remote from the first semiconductor layer and has an effective complex refractive-index for laser light discontinuous at both ends of the semiconductor layer remote from the first semiconductor layer.

Abstract: A semiconductor laser device comprises an n-type GaAs layer, an n-type GaAlAs layer disposed on the n-type GaAs layer, a laser active layer consisting of a p-type GaAs layer disposed on the n-type GaAlAs layer, a first p-type GaAlAs layer disposed on the laser active layer, the surface of which opposing said laser active layer is a periodically corrugated surface, a second p-type GaAlAs layer disposed on the periodically corrugated surface of the first p-type GaAlAs layer, a p-type GaAs layer disposed on the second p-type GaAlAs layer, and electrodes disposed on the n-type and p-type GaAs layers, respectively, and having a very low threshold value for laser oscillation.

Abstract: A semiconductor laser device capable of emitting highly collimated beams, especially of a narrow beam divergence, is disclosed. A striped hetero-junction is formed on a predetermined semiconductor substrate by a first semiconductor layer (refractive index: n.sub.1, band gap: Eg.sub.1, thickness: d), a second semiconductor layer (n.sub.2) and a third semiconductor layer (n.sub.3), and the hetero-junction is sandwiched between portions of a fourth semiconductor layer (n.sub.4, Eg.sub.4) into a buried structure. At this time, the various materials are selected to follow the relations of d.ltoreq..lambda. (where .lambda. denotes the oscillation wavelength of the semiconductor laser), n.sub.2, n.sub.3 <n.sub.4 <n.sub.1, and Eg.sub.1 <Eg.sub.4, and the effective refractive index of the first semiconductor layer (n.sub.1eq) is made smaller than n.sub.4.

Abstract: A semiconductor device including a GaAs layer having a periodic corrugation on a surface thereof with a GaAsAl layer disposed on the periodic corrugation is formed by contacting a solution consisting of Ga, Al and As heated at a temperature of about 700.degree. C. to the corrugated surface of the GaAs layer and cooling the solution to a temperature of about 670.degree. C. at a cooling rate of 5.degree. C./min. whereby the periodic corrugation is not transfigured so much.

Abstract: A semiconductor laser device comprises an n-type GaAs layer, an n-type GaAlAs layer disposed on the n-type GaAs layer, an optical confinement region comprising a laser active region consisting of GaAs disposed on the n-type GaAlAs layer, a first p-type GaAlAs region whose aluminum content is less than that of the n-type GaAlAs layer, disposed on said laser active region and a second p-type GaAlAs region whose aluminum content is less than that of the first p-type GaAlAs region, the surface of which opposite that disposed on said first p-type GaAlAs region is a periodically corrugated surface, a p-type GaAlAs layer whose aluminum content is more than that of said first p-type GaAlAs region, disposed on the periodically corrugated surface of the second p-type GaAlAs region, a p-type GaAs layer disposed on said p-type GaAlAs layer, and electrodes disposed on the n-type and p-type GaAs layers, respectively, and which has a very low threshold value for laser oscillation and which is fabricated with a very high yie