Abstract: An Electro-Optic modulation method and device using a low-energy oblique transition of a tightly coupled super-grid. According to the present invention, a luminous beam is injected into a tightly coupled super-grid and an electric field (E) is applied to the super-grid whose amplitude is made to gradually vary so as to cause the intensity of the beam to vary. This beam is injected parallel to the plane of the films of the super-grid which guides the injected beam. The electric field is weak and applied along the growth direction of the super-grid, which provokes the appearance of a low energy oblique transition (TB) in a domain of wavelengths where the super-grid is transparent in the absence of any electric field. The super-grid is one whereby the wavelength of the luminous beam is contained in this domain. Such a device may find application in optical telecommunications systems.

Abstract: Joint closure modules and boxes for optical fiber cables, also known as splice organizers, the module having a supporting plate demarcating a shielded space of extension of the fiber transfer sections, said supporting plate including, firstly, a set of aligned and separate means for anchoring the external sheath, the peripheral reinforcements and the central strength element, respectively, of each cable and, secondly, at least one fiber coiling and connection cartridge with guided hinging, arranged so as to limit the transfer length and the course of shift of said sections for the transfer of the guided shift of said hinged cartridge.

Abstract: Photoreceptor for frequency-modulated optical signals. The photoreceptor consists of a semiconductor laser (10) fed clearly beyond the threshold (12). The optical signal (20) to be demodulated is injected into the laser. The voltage (V) taken at the terminals of the latter reflects the frequency difference between the frequency of the signal (F1, F2) and the actual frequency (Fo) of the laser.

Abstract: The invention relates to a transmission-reception system for the transmission of animated color images or pictures and sound from two independent channels. The image signal is distributed over two independent channels, the luminance signal occupying one channel, while the chrominance signal, which is multiplexed with the sound, occupies with the sound the other channel. Separate luminance and chrominance signal processors are provided.

Abstract: Process for neutralizing acceptor atoms in p-type InP.This process consists of subjecting to epitaxy a p-doped InP layer (4) and then a not intentionally doped Ga.sub.0.47 In.sub.0.53 As layer (6) on an InP semiinsulating substrate (2), followed by hydrogenating the InP layer exposing the assembly to a hydrogen plasma (8) with a power density below 0.07 W/cm.sup.2 at the most 250.degree. C.

Abstract: A memory effect, monochromatic display of the photoconductor-electroluminescent type, includes on a substrate an electroluminescent layer and a photoconductor layer in stacked relation. The stack is interposed between two electrode systems used for exciting the electroluminescent layer, the latter having an emission spectrum overlapping the sensitivity spectrum of the photoconductor material. An optical filter is located between the electroluminescent layer and the display observer and permits the passage of that part of emission spectrum of the electroluminescent layer most useful for display purposes while blocking a region of the emission spectrum of the ambient illumination, the sensitivity spectrum of the photoconductor layer then being essentially contained in said region.

Abstract: Electroluminescent display screen with a memory and a particular configuration of electrodes. The display screen comprises on a nonconducting substrate a stacked electroluminescent film and a photoconductive film, both of these films being inserted between lower transparent electrodes (12) orientated along a first direction (x) and upper electrodes (22) orientated along a second direction (y) perpendicular to the first direction, the upper and lower electrodes defining at their intersection picture elements (26), the upper electrodes (22) comprising blocks (40) of dimension D along the first direction at the display points electrically interconnected by two access strips (42a, 42b) with a width d with d<D/2, the access strips at a given block being connected by a conductive access bridge (46) parallel to the lower electrodes, the edges of these blocks (40) being situated inside the edges of the lower electrodes.

Abstract: A photoconductive-electroluminescent, memory effect polychromatic display defining a first and second inverted structure. The first structure incorporates a first transparent substrate equipped with a first electroluminescent layer El.sub.1 placed between a first and a second electrode system, which are connected to a first electrical source for exciting certain zones of layer El.sub.1. The second inverted structure incorporates a second substrate equipped with a second electroluminescent layer El.sub.2 and a photoconductive layer stacked on one another. These two layers are inserted between a third and a fourth electrode system which are connected to a second electrical source for exciting certain zones of the layer El.sub.2. The electroluminescent layer El.sub.1 has a monochromatic or dichromatic emission spectrum and the electroluminescent layer El.sub.2 has a monochromatic emission spectrum essentially complementary to layer El.sub.1.

Abstract: A device for the electric characterization of samples, comprises a UHF resonator intended to be coupled locally to the sample. The resonator is formed by a microstrip or triplate line loop (20) carried by a conducting plane (16) and having a gap of small length with respect to the length of the loop and an assembly (32) for receiving the sample in a position in which the sample is coupled selectively to the edges of the gap without being interposed therebetween. The edges of the gap of the loop are fixed to two electrodes of small area passing through a thin plate of dielectric material having a flat face for application against the sample.

Abstract: A loop-back device is particularly designed to fit line terminals in half-duplex optical transmission systems thereby facilitating fault location in these transmission systems. An optical fiber coupler having a high crosstalk generates an echo in a reception channel of the terminal, from a test signal transmitted in a transmission channel of the terminal, to an optical transmission medium. Means are provided for cancelling transmission of the echo in the reception channel when the loop-back is de-activated, i.e. when a data signal is carried in the transmission medium, and for amplifying and regenerating said echo when the loop-back is activated, i.e. when said test signal is transmitted. A memory is used for delaying the echo and for transmitting it to a receiving circuit in the terminal during a signal reception period of the half-duplex transmission.

Abstract: The present invention concerns a method for manufacturing a buried stripe semiconductor laser comprising the steps of depositing by epitaxy at least the heterostructure (51, 52, 53, 54) comprising at least one active material layer (53) on a substrate (50) and then depositing a dielectric mask (55) over the structure thus obtained and etching the latter through the mask (55) to obtain stripes in the active material layer (53) and any layer or layers (54) previously deposited by epitaxy over the active material layer (53), then carrying out impurity ionic implantation in the structure, protecting the active material stripes (53) and any layer or layers (54) that may have been deposited over this material by means of a mask (55) that is not transparent to ionic implantation.

Abstract: A system embodying the invention for verifying signatures appended to bank checks comprises a check feed stand, a CMC7 code reader, a video camera and a control equipment. The checks are conveyed across the stand and are read in turn by the code reader and the camera which respectively issue the identity of the account holder and an image of the signature appended to the check. The control equipment is preferably comprised of a microcomputer in which algorithms are resident to authenticate the signatures by comparison with previously recorded reference signatures. The signatures are represented by static parameters relating to the shapes and dimensions of their drawings. The verification method embodying the invention therein comprises an optimization algorithm resident in the control equipment in order to specifically select for each signature the parameters that should be used to minimize a decision error.

Abstract: A spectrum analyzer for a variable amplitude and frequency electric signal includes an optical modulator responsive to the signal that derives a first optical wave having intensity and frequency components corresponding to the signal amplitude and frequency components. An optical analyzer responds to the first optical wave to derive a second optical wave having intensity variations at frequency components corresponding to the amplitude of the electric signal at the frequencies in the spectrum of the signal. The optical analyzer includes a tunable optical cavity responsive to the first optical wave to derive the second optical wave.

Abstract: A method of producing a quasi-flat semiconductor device capable of a multi-wavelength laser effect and the device thus produced.On the basis of a double heterostructure stack supported by a substrate comprising steps, following levelling of the stack and diffusion through a flat surface, a semiconductor device is obtained which is capable of a multi-wavelength laser effect, of which the different junctions are situated in a plane parallel with the base of the substrate.

Abstract: A device for the control and adjustment of the modal alignment of optical fibers is described. The device includes at least one laser (20) delivering an electromagnetic beam, and at least one mode selector (26) suitable for acting on the beam so as to produce a TEM1, j-1 type modal structure, the modal structure having an axis of symmetry (15). Also included in the device are a marker for marking at this axis of symmetry (15) orientation variations around an axis (RR1); an introducer for introducing the electromagnetic beam into an optical fiber (10); and a measurer (36) for measuring luminous power. The device is particularly adapted for the adjustment of the alignment of optical fibers as regards their connection and for centering an optical fiber in a plug connector.

Abstract: Process for producing a wall for an active matrix display screen.By a first etching is formed stack rows of layers (L) with a metal at the ttom. The gaps between the rows are filled by a negative polyimide. On the surface are etched columns (C) and blocks (P). These elements serve as a mask for an etching leaving control transistors in a gate configuration below the same.Application to the production of liquid crystal display screens.

Abstract: A method and installation are provided for broadcasting high definition television programs, particularly for broadcasting HD-MAC programs on a narrow channel, while reducing degradation of the picture when received by a first generation MAC receiver. The signal obtained by analysis of the source picture is subjected to spatio-temporal subsampling and to non-linear motion compensation filtering, leading to transmitting the points representative of the same source frame over at least two successive transmission frames (t1, t2) and transmitting, at the same time, assistance data defining a motion vector field. To improve the compatible frame delivered by a first generation receiver, the second analysis field corresponding to the same source frame is subjected to time attenuation in the direction of motion.

Abstract: Active matrix display screen comprising a matrix of display points and, between these points, addressing lines (Ln) and addressing columns (Cp), each point (Pn,p) being connected by a thin-film transistor (Tn,p) to a line (Ln) and a column (Cp). The screen is characterized by the fact that each point is further connected by a second transistor (Tn+1,p+1) to the next line (Ln+1) and to the next colunn (Cp+1). The effects of column breaks are thus eliminated.

Abstract: A system and process for controlling the flow of packets carried by asynchronous time multiplex (EPACi) channels. The packets from one communication link are identified by their label and the identity of the multiplex channels which carries them. The process is comprised of allocating for each communication a predetermined clock rate and a predetermined threshold value, measuring the difference between the number of packets entering belonging to the communication and the number of pulses generated by the clock, lower bounding this difference, and, if the difference reaches a predetermined threshold, triggering a signal (DEP) which causes the detection of packets belonging to the communication in question as long as the difference is not less than the predetermined threshold.

Abstract: The invention relates to a process for the preparation of berlinite crystals AlPO.sub.4, with a high Q factor, from seeds or crystalline flakes of AlPO.sub.4, by a hydrothermal method. It is characterized in that the crystallization solution is a sulfuric solution of AlPO.sub.4. The invention also relates to the berlinite monocrystals obtained by this process.