Abstract: The invention relates to a method and a system for predicting maintenance operations on a current aircraft engine, comprising: processing means to compare a set of failure models (M1, . . . , Mn) adapted to said current engine to select a relevant failure model (Mi) with a failure age (T0) defining the age of said engine at the time of the failure; processing means to associate decision rules (R) about the workscope on said current engine with said relevant failure model (Mi), as a function of a set of parameters (P1, P2, Pi) related to said current engine; and processing means to determine the required maintenance workscope (Wf) to be applied to said current engine, as a function of said decision rules.

Abstract: The invention relates to a method and a system for predicting maintenance operations on a current aircraft engine, comprising: processing means to compare a set of failure models (M1, . . . , Mn) adapted to said current engine to select a relevant failure model (Mi) with a failure age (T0) defining the age of said engine at the time of the failure; processing means to associate decision rules (R) about the workscope on said current engine with said relevant failure model (Mi), as a function of a set of parameters (P1, P2, Pi) related to said current engine; and processing means to determine the required maintenance workscope (Wf) to be applied to said current engine, as a function of said decision rules.

Abstract: An integrated semiconductor device including at least one optoelectronic switching element, which comprises:two rectilinear monomode optical guides crossing each other at an angle 20.theta. composed of at least one heterostructure of III-V material, which comprises a substrate S of a confinement material and a guiding layer C.sub.G as well as a guiding strip RB,a p-n junction formed in the crossing region asymmetrically with respect to the bi-secting longitudinal plane of the crossing angle,characterized in that the longitudinal dimension of the p-n junction largely exceeds that of the crossing region, and in that the p-n junction is arranged so as to project symmetrically on either side of this region in this longitudinal direction.

Abstract: A semiconductor device comprising an integrated optical guide, which has at least one rectilinear part and one curved part, and comprising means for obtaining the confinement of the light in the guide in the curved part, which means include a groove provided along the edge of the guide in the region of the curve part, characterized in that these means also include a guide structure comprising a guiding layer and, overhanging the guiding layer, a ribbon in relief for determining the optical path followed by the light in the guiding layer, and in that these means moreover include a groove structure such that it has a constant depth, that its central part follows extactly the edge of the guiding ribbon in the curved part, that its ends are removing from the edge of this ribbon at the beginning and at the end of the curved part, that its bottom is disposed in the guiding layer at a level which does not reach the lower part of this guiding layer.

Abstract: A method of manufacturing semiconductor devices is set forth using reactive ion plasma etching in which an optical grating is formed to etch underlying regions, such as dielectric material, semiconductor material, or alternate layers of different semiconductor material. The optical grating is formed with a rectangular profile having grooves and mask strips on a sample material where each of the grooves has a width L.sub.S substantially equal to the width L.sub.M of the mask strips. The optical grating is formed of a material which may be one of a photoresist, a dielectric compound, a metal, or a metallic compound. This method enables control of reactive ion etching during manufacture of integrated circuits of III-V compounds.

Abstract: A method of manufacturing semiconductor devices comprising at least a reactive ion etching step of a so-called substrate formed by semiconductor compounds having the general formulae Ga.sub.1-x As.sub.x In.sub.1-y P.sub.y, in which formulae x and y are the concentrations and lie between 0 and 1, this method comprising for carrying out this etching step a masking system of the said substrate cooperating with a flow of reacting gases, characterized in that the masking system is formed by a first metallic layer of titanium (Ti) of small thickness, on which a second metallic layer of nickel (Ni) is disposed having a thickness of about ten times larger, and in that the flow of reacting gases is formed by the mixture of the gases Cl.sub.2 /CH.sub.4 /H.sub.2 /Ar, in which mixture Cl.sub.2 is present in a quantity of about a quarter of the quantities of CH.sub.4 and Ar, as far as the partial pressures in the etching chamber are concerned.Application: Manufacture of optoelectronic devices of III-V materials.