Abstract: The invention concerns an underwater water treatment unit which has specific cleaning means which are suitable for cleaning filtration membranes in the unconventional conditions associated with use at great or very great depths, as well as a method for cleaning the membrane of the underwater water treatment unit.

Abstract: The invention concerns an underwater water treatment unit which has specific cleaning means which are suitable for cleaning filtration membranes in the unconventional conditions associated with use at great or very great depths, as well as a method for cleaning the membrane of the underwater water treatment unit.

Abstract: The invention concerns an underwater water treatment unit which has specific cleaning means which are suitable for cleaning filtration membranes in the unconventional conditions associated with use at great or very great depths, as well as a method for cleaning the membrane of the underwater water treatment unit.

Abstract: An electrooptical modulation device formed on an electrooptical substrate, including a first region having a Y-junction for receiving an optical signal to be modulated and dividing the optical signal into two equal optical signals, a first modulation region of length L.sub.1 having two parallel optical waveguides spaced sufficiently apart to prevent optical coupling, a second section of length L.sub.2 over which the optical waveguides extend and define a coupling length l.sub.c2, this second section not being subjected to electrooptical modulation, a second modulation region of length L.sub.3 having two parallel optical waveguides, a third section of length L.sub.4 over which the optical waveguides extend and define a coupling length l.sub.c4, and a fourth section for separating the optical waveguides and delivering two modulated optical signals of different intensity. This device operates with reduced control voltages and makes it possible to enhance the linearity of the electrooptical response.

Abstract: An electro-optical modulator system obtained by linking a modulator incorporating a Y-junction coupler having a length Ll(101-108) to a passive coupler (104,105) whose length L2 in relation to the coupling length LC2 is determined so as to cancel substantially the third order distortions of the modulator. The resulting modulator has all of its even distortions cancelled and its uneven distortion is substantially zero. Furthermore, the rate of decay can potentially be zero.

Abstract: This e.g. Z-propagating, X-cut LiNbO.sub.3 :Ti splitter comprises an alternating delta beta directional coupler (39) able to introduce, in the absence of a voltage between its electrodes, a delta beta variation between its propagation constants, which is (a) independent of the polarization state of the guided lightwave and (b) such that the representative point of the coupler on its control diagram is the center of a segment parallel to the abscissa axis of the reference frame in which the diagram is plotted, and defined by two curves respectively corresponding to parallel states and crossed states of the coupler. Application to integrated optics.

Abstract: This polarization beam splitter for guided light is e.g. produced on Z-propagating, X-cut LiNbO.sub.3 :Ti and comprises in series a passive Y-junction (66), an active phase shifter (68) and an active directional coupler (70), independent of the polarization and able to constitute a 3 dB coupler. Thus, on supplying a light wave to the input of the Y-branch and with the coupler constituting a 3 dB coupler, the TM and TE modes of the input wave are respectively obtained at the outputs of the coupler by appropriately polarizing the phase shifter. Application to optical fiber sensors or transducers and to the coherent transmission of information by monomode optical fibers.

Abstract: This invention relates to an increase in the low longitudinal resonance frequencies of microwave transmission lines known as symmetrical lines, comprising two coplanar and parallel narrow conductive strips. According to the invention, the line further comprises a longitudinal and wide planar conductive strip which is parallel to one of the narrow strips at a sufficient distance not to substantially disturb the characteristic impedance of the initial symmetrical line and which is connected to the narrow strip by small planar end conductors thereby forming a longitudinal flat cavity. The cavity offers a first resonance frequency much greater than those of the initial symmetrical line and consequently affords a higher useful frequency bank of signals to be transmitted. The end conductors allow the line to be connected to coaxial connectors. In other embodiments, the cavity is divided into several resonant sub-cavities in order to raise the pass-band.

Abstract: A process and device for connecting an optical fibre and an integrated optical component comprising a wave guide. The fibre and the component each have an end adapted for connection. The component is attached to a main support. The fibre is attached to a fibre support so that the end of the fibre extends beyond such fibre support. The end of the fibre is attached to the end of the component so as to allow light to pass from the fibre to the component and conversely. Then the fibre support and the main support are rigidly connected to each other.