Abstract: A monolithically integrated waveguide-photodiode combination for optical communications systems includes a carrier substrate of n-conductive semiconductor material, a further layer of the same material in whose surface is formed a strip-shaped n-conductive absorption layer, and of a waveguide formed thereon. A p-doping is diffused into the waveguide through the n-conductive absorption layer and a photodiode is thereby formed. A contact for the positive electrode of the photodiode is applied over the p-conductive region and the contact for the negative electrode is applied to the free side of the carrier substrate. The waveguide is covered by a cover layer along its top surface.

Abstract: A monolithically integrated WDM demultiplex module has a film wave guide of InGaAsP fashioned on a substrate, a photodiode of InGaAs being applied to the film wave guide. The photodiode is optically coupled to the film wave guide by a leakage coupling. A wavelength selection element in the form of a grating is provided in the surface of the film wave guide. The module can be manufactured with a single epitaxial step. Structures for increasing the crosstalk attenuation of the module and for a better coupling-in of radiation into the module are provided.

Abstract: An integrated structure for bi-directional optical fiber transmission has a laser diode, a photodetector, and a bi-directional optical waveguide integrated on a common substrate, the waveguide guiding radiation from the laser diode out of the structure and directing incoming radiation of a different wavelength through the structure to the photodetector. The structure also includes a passive optical component cooperating with the strip waveguide for substantially isolating the radiation propagated in one direction in the waveguide from the laser diode, and substantially isolating the radiation propagated in the opposite direction in the waveguide from the photodetector. A method for manufacturing this structure includes essentially growing two epitaxial multi-layer structures spaced from each other and covering selected portions of the substrate constituting the laser diode and the photodetector, with the strip waveguide extending therebetween.