Abstract: A semiconductor laser having a double heterostructure configuration is provided with a light waveguide layer extending between a pair of mirrors. A thin active layer is disposed adjacent to the waveguide layer, and is formed in the shape of a stripe having a width of approximately 5 .mu.m. The stripe is shorter in axial length than the waveguide, such that the ends of the stripe are spaced from the mirrors by a distance of 30 to 60 .mu.m.

Abstract: In a stripe geometry buried double heterostructure semiconductor laser device, a first semiconductor layer for effecting laser oscillation upon injection of carriers is sandwiched between second and third semiconductor layers having a wider band gap than the first semiconductor layer. This double heterostructure is partially rendered mesashaped to provide a stripe geometry, and the vacancy resulting from mesa formation is filled with a fourth semiconductor layer having a wider band gap than the first semiconductor layer. In this invention, the region of the first semiconductor layer which is spaced from both end facets of the device by a distance at least equal to the diffusion length of carriers has a narrower band gap that the other regions of the first semiconductor layer.

Abstract: In an active layer restricted by a pair of heterojunctions in a semiconductor laser, a stripe region and a contiguous region are made to have a difference in kinds and/or concentrations of impurity to give the stripe region a higher dielectric constant, preferably by about 0.01-1%, than the contiguous region whereby transverse laser oscillation confined to the active layer by the heterojunctions is further confined to the stripe region in a width direction parallel to the heterojunctions. The dielectric constant profile established in the active layer stabilizes the transverse mode and eliminates nonlinearities in the laser output - exciting current curve as well as other undesirable performance characteristics that are exhibited in conventional stripe-geometry lasers. The difference in the impurity gives the stripe region a narrower band gap of from about 5 to about 100 meV than the contiguous region.

Abstract: A semiconductor laser device in which at least one of the main surfaces of a semiconductor laser crystal body which generates heat during operation is brought into thermal contact with a silicon crystal heat-sink body.

Abstract: A hermetically sealed injection semiconductor laser device includes a hollow cylinder in which a crystal laser pellet is enclosed. The ends of the cylinder are sealed by metal electrodes one of which projects axially into the cylinder and is connected to an electrode surface of the crystal pellet. A lens element is disposed within the cylinder.

Abstract: A strip-geometry semiconductor double-heterostructure laser device includes an n-GaAs substrate on which a first layer of n-Al.sub.x Ga.sub.1-x As and a second layer of p-AlyGa.sub.1-y As are formed by epitaxial growth techniques. A third layer of heat- and Ga melt resistant material of narrow stripe geometry is formed on the second layer. After the second layer and part of the first layer, except for their stripe portions, are meltbacked by Ga melt liquid, a fourth layer of n-Al.sub.z Ga.sub.1-z As is formed by epitaxial growth techniques of the same Ga melt liquid in one process.