Abstract: The present invention relates to a device for both-way transposition between optical signals and electrical signals, for a communications system, said device comprising a vertically integrated component comprising an optically driven oscillator based on a negative differential conductance mechanism, for performing optical-to-millimetric conversion on the down path, and an asymmetric Fabry-Perot cavity modulator for performing the electrical-to-optical conversion function on the up path.

Abstract: This invention relates to a process for producing a matrix of "all optical" vertically-structured quantum well components.This process consists in the encapsulation of a half-structure constituted by a lower mirror (2) and an active zone (3) partially covered by a self-alignment mask (4) with a negative dielectric layer (7) whose thickness is given by the Bragg condition at the working wavelength. The encapsulated half-structure is thermally treated to induce an alloy interdiffusion (9) in the non-covered parts of the active zone, and covered with one or several negative and positive layers (10,11) so as to complete the upper Bragg mirror.

Abstract: This invention relates to a process for producing an electrically controllable matrix of vertically-structured quantum well components from a substrate on which a lower Bragg mirror has been "epitaxiated", which said mirror is made up of one or several alternations of semiconductor thin layers surmounted by an active layer consisting of compound III/V-based quantum well heterostructures, characterized in that:a) the active quantum well layer is encapsulated with a dielectric layer capable of inducing an alloy interdiffusion in the quantum well layer,b) the said dielectric layer (3) is etched in such a way as to create a self-alignment mask (4),c) the substrate covered by the self-alignment mask is treated thermally so as to create modified regions (7) by alloy interdiffusion in the active layer,d) an upper mirror (8), in semiconductor material doped inversely to the lower mirror, is deposited by epitaxial growth in the recesses of the mask with regard to the regions of the non-interdiffused active zone,e) the

Abstract: A process and apparatus for the modulation and amplification of light beams having at least one input light beam (8) supplied to at least one Fabry-Perot resonator having at least one resonance mode, and defined by two mirrors (M1,M2) and produced by stacking layers on a substrate (4). At least one of the layers form an active medium (6) able to amplify the input light beam by stimulated emission, the wavelength thereof being around the resonance of the resonator and the density of free charge carriers in the active medium being varied in such a way as to make the latter sometimes absorbent and sometimes an amplifying with respect to the input beam and thus obtain at least one output light beam (10) whose intensity is modulated and amplified relative to the input beam. Application to optical telecommunications and to optical interconnections.

Abstract: Gas photonanograph for the production and optical analysis of nanometer scale patterns. The photonanograph has a gas expansion chamber equipped with a gas supply for producing patterns and provided at a first end with microcapillaries for the discharge of the gas, an optical fibre, which is sharp at a first end and which is to be positioned facing the sample to be treated, a light source coupled to the second end of the optical fibre, the latter being transparent to the light emitted by the light source, and detecting and processing apparatus for monitoring a light signal reflected by the sample. The photonanograph permits the localized etching or deposition of materials for microelectronics or microoptoelectronics.

Abstract: Guided-wave photoreceptor based on quantum wells made of semiconductor materials, particularly for coherent communications system with polarization diversity.This photoreceptor has at least one pair composed of a first photodetector (76) and a second photodetector (78). At least the first photodetector is formed on a semiconductor substrate (94) and has a multilayer ribbon with multiple quantum wells made of semiconductor material (100); this multilayer ribbon is provided to guide an incident light; the first photodetector is capable of absorbing the transverse magnetic component of that light, whose electrical field has a component perpendicular to the plane of the multilayer; the transverse electrical component of that light is virtually not absorbed in the first photodetector; the second photodetector is provided to absorb this transverse electrical component.

Abstract: Heat flash vapor phase deposition process of an insulating layer on a III-V material substrate and its application to the production of a MIS structure. Using the same enclosure, said process comprises carrying out an ethching of a III-V substrate (2), forming on said substrate at least one protective layer (8,10) for the substrate surface constituting the active zone (6) of the MIS structure, or even producing the active layer by epitaxy, depositing an insulating layer (12) by CVD at high temperature produced by irradiating the surface of the sample (1) with tungsten halogen lamps and optionally forming on the insulating layer (12) a conductive layer (14) at high temperature by irradiation with tungsten halogen lamps, thus completing the MIS structure.

Abstract: A process for forming a flux of atoms of an element which includes the forming of a target made up of the element and the irradiation of the target by a pulsed laser whose energy density per pulse is equal to or greater than the emission threshold of the atoms of the elements, but which energy density is below the ablation threshold of either one of the element or the compound which forms the target. The process also relates to the deposition of an insulating, semiconductor or metallic layer of an element or a binary, ternary or quaternary compound which is optionally doped and which utilizes the steps of a heating of a substrate and the growing on the heated substrate of an epitaxial layer of either the element or the compound from at least one atomic flux. The atomic flux is produced by irradiating of a target through the use of a pulsed laser.