Abstract: The invention relates to a modulation ratio amplification device, particularly for amplification at UHF. This device comprises means for making two optical waves, which are of the same amplitude but offset in frequency, interfere. These means may be a frequency converter, coupled to a continuous phase shifter; they may also involve two phase shifters: one continuous, the other varying sinusoidally over time. This type of device makes it possible greatly to amplify the desired modulation ratio, using an optical amplifier, given that the continuous background of the optical signal is suppressed.

Abstract: A semi-conducting structure delimits two quantal wells (CP1, CP2) connected across a barrier layer (CB). The application of an electric field to the structure makes possible the transfer of electrons from one of the wells to the other. The electron-hole pairs are created by a wave-pump, or by the doping of one of the wells. This makes possible, in particular, a dual control by means of the wave-pump and the electric field, thus creating an "AND"-function modulator.

Abstract: A separation structure for selecting the propagation mode of the light waves in a light wave guide, the latter being constituted by a strip (100) of a semiconductor material having a first refractive index formed on a semiconductor substrate (10) of a material having a second refractive index lower than the first index and such that the light is confined in the strip forming the guide. The structure is arranged in the path of the light beam in such a manner that it de-limits in the guide on the one hand at least one region (G.sub.1), in which the propagation of the light wave is monomode, and on the other hand a region (G.sub.11), in which the propagation is bimode. According to the invention the said separation structure is formed by an abrupt variation of the dimension of the guide perpendicular to the substrate, the flat surface of the substrate being chosen as reference for the measurement of this dimension in such a manner that, by defining e.sub.

Abstract: An optical switching element including two parallel light wave guides, whose opposite walls are mutually separated by a small distance (d), the so-called coupling distance, each constituted by a strip of a semiconductor material formed on a semiconductor substrate having a refractive index lower than that of the guides, these guides each transporting a monomode wave and the switching being initiated by the effect of polarization means applied to the guides, characterized in that the strip constituting one of the guides (G.sub.1) designated as first guide is formed as a first uniform layer on the substrate (1), in that the strip constituting this guide is covered by a uniform intermediate layer (I) of a compatible semiconductor material, having an index lower than that of the guides and having a thickness which forms the coupling distance between the two guides, in that the strip constituting the other guide (G.sub.

Abstract: A coupling member between an input light wave guide transporting a main light beam and secondary light wave guides each transporting a part of the intensity of the main light beam. The coupling member is monolithically integrated with the wave guides on a semiconductor substrate. The coupling member comprises a plate having parallel surfaces perpendicular to the plane of the substrate. The plate has a refractive index different from that of the main light wave guide. The parallel surfaces of the plate form interfaces separating the propagation medium of the wave guides (I, R, T) from the propagation medium constituted by the plate.

Abstract: A semiconductor device comprises a wave guide which permits propagation of light in the range of wavelengths between 0.9 and 1.6 .mu.m. This wave guide is formed on a crystallographic oriented substrate of monocrystalline semiconductor material from the group III-V covered with a layer of a dielectric material. Grooves are etched in the dielectric material according to the configuration chosen for the wave guide, and correspondingly into the substrate. The wave guide is obtained by anisotropic epitaxial growth of the III-V semiconductor material from the substrate in these grooves, and is bounded on its lateral and upper parts by crystallographic faces having a specific orientation relative to the plane of the substrate surface. The attenuation obtained for such wave guides is of the order of 1 dB/cm for light having a wavelength of 1.06 .mu.m.