Abstract: A semiconductor laser including a compound semiconductor substrate of an n-type, a semiconductor laser chip region defined at a center portion of an upper portion of the compound semiconductor substrate and provided at its front and rear surfaces with mirror surfaces for oscillating laser beams, and a pair of guide regions defined at opposite sides of the chip region, respectively, to be in contact with the semiconductor laser chip region. The chip region has a shape of a hexahedron. Together with the front and rear surfaces of the chip region, the guide regions define a cavity for coupling the chip region with external elements at the compound semiconductor substrate. The semiconductor laser also includes a first electrode formed over the chip region and guide regions and adapted to receive an electric power for generating laser beams and a second electrode formed beneath the semiconductor substrate and adapted to receive the electric power for generating laser beams, together with the first electrode.

Abstract: A semiconductor laser diode includes a semiconductor substrate, an active layer having a double hetero structure formed on the semiconductor substrate, a first quantum well layer formed between the active layer and the current confinement layer, a second quantum well layer formed on the active layer corresponding to the current injection groove, and a clad layer having its flat surface formed on the current injection groove and the current confinement layer. A method for manufacturing the semiconductor laser diode includes the steps of forming an active layer having a double hetero structure on the semiconductor substrate, selectively forming a current confinement layer on the active layer to form a current injection groove, forming a clad layer having its flat surface on the current injection groove and the current confinement layer.

Abstract: A semiconductor laser including a compound semiconductor substrate of an n-type, a semiconductor laser chip region defined at a center portion of an upper portion of the compound semiconductor substrate and provided at its front and rear surfaces with mirror surfaces for oscillating laser beams, and a pair of guide regions defined at opposite sides of the chip region, respectively, to be in contact with the semiconductor laser chip region. The chip region has a shape of a hexahedron. Together with the front and rear surfaces of the chip region, the guide regions define a cavity for coupling the chip region with external elements at the compound semiconductor substrate. The semiconductor laser also includes a first electrode formed over the chip region and guide regions and adapted to receive an electric power for generating laser beams and a second electrode formed beneath the semiconductor substrate and adapted to receive the electric power for generating laser beams, together with the first electrode.

Abstract: A dielectric ceramic composition for sintering at a low temperature for use in capacitors which comprises a dielectric ceramic composition represented by the formula (Pb(Zr.sub.1/2 Ti.sub.1/2)O.sub.3)x, (Pb(Mn.sub.1/2 W.sub.1/2)O.sub.3)y and (Pb(Zn.sub.1/2 W.sub.1/2)O.sub.3)z, wherein x plus y plus z equal 1.