Abstract: An improved buried heterostructure semiconductor laser comprises high resistive burying layers positioned at both sides of an active region so that the high speed modulation is possible to be performed and the higher quantum efficiency is obtained for the reason why the capacitance and leakage current are diminished. A further improved buried heterostructure semiconductor laser comprises spacer layers between an active region and respective high resistive burying layers so that the reliability is maintained to be high for the reason why the diffusion of an impurity is avoided from the respective high resistive burying layers to the active region.

Abstract: A surface-emitting semiconductor light emitting element, such as a laser or a light emitting diode, having at least one active light emitting layer on a semi-insulating substrate, with p-type and n-type semiconductor regions also on the substrate and in contact with opposite side faces of the active layer. The active layer has a narrower band gap than the semiconductor regions. The light emitting region may comprise a multilayer structure of plural active light emitting layers sandwiched between alternating p-type and n-type semiconductor layers.

Abstract: A method of growing an InGaAsP layer on a corrugated InP substrate as a part of a procedure for producing a DFB semiconductor laser includes the step of heating the substrate up to temperatures approaching 700.degree. C. while holding the substrate in an atmosphere which contains arsine and phosphine. The substrate is subsequently moved to InGaAsP and InP growth chambers for growth of these respective layers. The method of the invention is advantageous in that the corrugated structure of the substrate is maintained intact throughout the procedure.

Abstract: A method of manufacturing optical fibers by applying to a substantially cylindrical thin glass member layers of porous glass having a radially varying composition by means of pulverized glass generators. The porous glass layers are heated and defoamed to form a transparent glass preform containing the thin glass member which preform is heated and drawn to reduce the cross-sectional area to form an optical fiber.