Abstract: In a semiconductor laser, an active layer and a pair of cladding layers sandwiching therebetween the active layer are provided to be parallel to the plane of the substrate to form a light waveguide passage, and light from the light waveguide passage is guided toward the substrate by reflecting the same at reflecting layers formed of dielectric with the active layer and the cladding layers being cut to have slopes inclined at approximately 45 degrees with respect to the plane of the substrate. A multiquantum well layer is provided so as to change the transmittance thereof by the change of applied electric field providing extremely high speed modulation. One or more through-holes may be made in the substrate so as to derive output light therethrough. One or more of the through-holes may be filled with a reflection layer so as to selectively reflect particular wavelength light, and thus by using a plurality of such laser chips, oscillation at different wavelengths is possible.

Abstract: A semiconductor laser device has a compound semiconductor substrate, a first semiconductor layer disposed on the compound semiconductor substrate, and a second semiconductor layer disposed on the first semiconductor layer. The second semiconductor layer has at least three thin film layers of at least two different semiconductor compounds, the film layers being laminated with the different semiconductor compound layers alternating. An electrically isolating region extends through the thickness of the second semiconductor layer and electrically divides the second semiconductor layer into first and second portions which differ in quantum level from each other. A third semiconductor layer is disposed on the second semiconductor layer, and first and second electrodes are disposed on the third semiconductor layer in positions for supplying current to the first and second portions, respectively, and a third electrode is disposed on the substrate at the surface thereof opposite to the first and second electrodes.

Abstract: A layer of a compound semiconductor having good quality is formed by disposing a substrate in an epitaxial growth layer, feeding a second reactant gas through a guide member extending from the downstream side to the upstream side of the flow of a first reactant gas, mixing the first reactant gas and second reactant gas, and supplying the resultant gaseous mixture of the first and second reactant gases onto the substrate.