Abstract: The present invention relates to a system for optical transmission in free propagation mode of one digital data signal in the atmosphere, with autocompensation of the turbulence effects. It applies especially to optical telecommunications. According to the invention, the system comprises light emission means and optoelectronic detection means suitable for detection around one given non-zero detection frequency. The emission means simultaneously emit, for each signal to be transmitted, two light waves at least one of said waves being intensity-modulated by said signal. Detection then takes place at a detection frequency equal to the difference between said frequencies of the light waves emitted.

Abstract: A synchronization device which synchronizes signals transmitted from a transmitter to receivers. The transmitter includes a generator for generating a synchronization signal having a recurrence period substantially equal to the minimum resolution of the journey time between the transmitter and the receiver. Each receiver includes a controllable delay for delaying the synchronization signal and a synchronization loop downstream of the delay. The synchronization loop includes a semi-reflecting plate, a correlator and a device for slaving the delay depending on the correlation. A signal received by the receiver is synchronized when the correlation function of the two successive recurrences of the synchronization signal passing through the semi-reflecting plate is at a maximum. The device may be used for accurate synchronization of information distributed from a transmitter to mutually remote receivers, for example for operating complex electromagnetic or optical rigs.

Abstract: An optical control device for an electronic scanning antenna having at least two controlled radiating elements, and including means for providing first and second mixed light beams, the first light beam polarized according to a first direction and having a first wavelength (&lgr;1), and the second light beam, polarized according to a second direction and having a second wavelength (&lgr;2); at least two optical delay circuits each receiving the first and second mixed light beams and configured to induce complementary delays compared to a determined time value on the first and second beams; chromatic separators each situated at the output of a corresponding one of the delay circuits and configured to separate the light having the first wavelength (&lgr;1) from the light having the second wavelength (&lgr;2); first photodetectors each coupling a corresponding radiating element to a corresponding chromatic separator; second photodetectors each coupling a corresponding chromatic separator to a corresponding first

Abstract: A UHF phase shifter including a UHF waveguide having an electrooptical element lying between two elements 3 and 4 made of materials which have permittivity higher than that of the electrooptical element. An electric polarization field is applied for controlling the electrooptical element and a UHF line is inserted into the element. The control of the orientation of the molecules of the electrooptical element allows for a variation of the index of the element as seen by the field of a UHF wave.

Abstract: The invention relates to a programmable transverse filter required for the matched filtering of signals with very wide passband. The signals to be filtered modulate one or more optical carriers (F1) in a modulator (MOD). Each carrier is distributed over several channels by a distributor (DIV). A delay creation circuit (CR1 to CRn) is provided in each channel. These channels are next summed after having been correctly delayed and assigned a coefficient characteristic of the signal to be detected.

Abstract: Device for creating optical delays in which several secondary optical paths are provided and placed in series and in shunt with a main optical path. Access to the secondary optical paths is obtained via switches that are placed along the main optical path. The length of the delay circuits are in a geometric progression whose common ratio has the value of two. Depending upon the switching states of the switches it is therefore possible to obtain a series of equal distant delays with a relatively small number of switches.

Abstract: A device for the optical processing of electrical signals. An optical source (L) emits a multiple-wavelength optical beam (B1). A modulator (MOD) modulates this beam. An optical fiber (F) receives the modulated beam and delays the components corresponding to the different wavelengths differently. A dispersive grating disperses wavelengths contained in the modulated beam in different directions. A spatial light modulator controls the level of optical intensity of different directions of the dispersed beam. An optical detection system receives the beam processed by the spatial light modulator. Such a device may find particular application to a transverse filter and microwave signal correlator.

Abstract: An optical architecture enabling the intercorrelation of two instantaneous wideband temporal signals. The beam coming from a monomode laser is used to obtain two carriers (W1, W2) for signals R(t) and S(t) by the use of, for example, integrated optical modulators (mod1, mod2). These two carriers have orthogonal polarizations and are distributed in a 2D structure comprising spatial light modulators as well as polarization separator elements. P.times.P independent channels (Cl to Cn) are thus formed. Their detection on a matrix of photodetectors (modl to modn) makes it possible to obtain, on each of them, the intercorrelation signal for different delays of the signals R(t) and S(t).

Abstract: A non-linear optical fiber receives two light waves by its two ends, each light wave being modulated by means of two modulators. These light waves create photoinduced index variations in the fiber which are proportional to the intensity of the optical field. A reading source emits a reading wave in the fiber. This reading wave is reflected at least partially by the index variation or variations. A detector receives the reflected wave and makes it possible, through the computation of the returning time of the wave, to determine the position of the index variations. Applications: very wide passband signal correlators.

Abstract: Disclosed is a method for the making of microlenses for optical applications (display for example) resulting from the deposition of a liquid on a substrate, the surface of which has been locally modified so as to increase the wetting capacity of the liquid thereon. The substrate may be a polymer and the wetting liquid may be an organic fluid capable of hardening by an adapted treatment.

Abstract: In an imaging process and system by transillumination of a medium illuminated by transparency by a beam, an acoustic transducer emits an acoustic wave in the medium which interferes with the beam. The frequency of the light passing through the medium is then shifted from the value of the frequency of the acoustic wave. A collimating device whose object focus is located at the intersection of the acoustic wave and the light beam collects the light diffused by the medium.