Abstract: A driving shaft having splined male and female shafts. The spline tooth pattern of the male shaft seen in a cross-section comprises an inclined portion substantially similar to those of a symmetrical spline tooth pattern of a conventional male shaft, and an outwardly convex and gently curved portion starting from the outer end of the inclined portion and terminating in a smaller diameter portion at the bottom of the tooth pattern. The radius of the smaller diameter portion and the tooth width at the bottom of the tooth pattern are larger than those in the symmetrical spline tooth pattern of the conventional male shaft, thereby obtaining an improved driving shaft to transmit greater rotating torque. The spline sliding portion of the female shaft is formed from a hollow tube by press-forming in a manner that the outer diameter of the press-formed portion is larger than that of a hollow blank tube, thereby increasing the torque transmission diameter to reduce surface pressure resulting in prolonged service life.

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.