Abstract: A Pockels-effect electro-optical modulator including a light guide having a core made of an inorganic amorphous material, and on which a structure is superposed that is made up of two electrode-forming layers between which an electro-optical polymer is interposed, said modulator being characterized in that said structure is superposed directly on the material of the core of the light guide. The transitions between the active and passive zones are advantageously adapted to minimize losses.

Abstract: This invention relates to a directional optical coupler including at least two optical guide cores (26, 28), in silica, lying on a cladding (24) in a mineral dielectric material, and a covering layer (30) in a polymer material, which covers the two optical guide cores, and whose index is less than that of the optical guide cores.

Abstract: The invention relates to a crosslinkable material containing a polymer onto which chromophores are laterally grafted, characterized in that each chromophore is within a polymer unit which corresponds to the following formula (I): ##STR1## in which: X represents a part of the polymer chain,A is a group --NO.sub.2, --CN, --C(CN).dbd.C(CN).sub.2 or --SO.sub.2 R.sub.4, R.sub.4 being a C.sub.1 to C.sub.6 alkyl,D is a nitrogen, sulphur or oxygen atom,R.sub.1 is a hydrogen atom or a C.sub.1 to C.sub.6 alkyl if D is a nitrogen atom, or nothing if D is a sulphur or oxygen atom,R.sub.2 is a C.sub.1 to C.sub.6 aliphatic alkyl group,and E is a group chosen from --OH, --O--CO--(CH.sub.2).sub.n --COOH, --O--W, --O--CO--R.sub.3 O--W and --O--R.sub.3 --O--W, n being an integer between 2 and 6, W being a photodimerizable group and R.sub.3 being a C.sub.1 to C.sub.6 alkyl,and the said material additionally containing complementary anchoring functional groups capable of attaching themselves to E during the crosslinking.

Abstract: A liquid crystal display screen which includes a first transparent plate covered with an electrode array and a second transparent plate covered with a counter-electrode. A liquid crystal film is inserted between the first and second plates. Further, either of the first or second transparent plates is covered with a material coating which diffuses ambient light with a brightness which exceeds a brightness of the liquid crystal film in the absence of excitation. This coating may take the form of a metal, a white mineral pigment or a polymer film which contains surface microcracks. Such a liquid crystal display screen as in the present invention may find particular applications to terminals, computers, pocket calculators, etc.

Abstract: The invention relates to a crosslinkable material that is active in non-linear optics, containing a polymer which carries chromophores each included in a polymer unit of formula: ##STR1## in which: T is part of the polymer chain,A is an --NO.sub.2, --CN or --C(CN).dbd.C(CN).sub.2 group,R.sub.1 is a hydrogen atom or a methyl or ethyl group,R.sub.2 is a CH.sub.2, C.sub.2 H.sub.4, C.sub.3 H.sub.6 or C.sub.4 H.sub.8 group, and:either X=Y is an azo group, F being a hydrogen atom and G being a group --C(O)--O--W or a group --C(O)--O--(CH.sub.2).sub.n --O--W, n being an integer between 2 and 6 and W being a hydrogen atom or a dimerizable group,or X=Y is an azomethine group, one of the groups F and G being a group --O--W or --R.sub.3 --O--W, R.sub.3 being a group --O--C(O)--R.sub.4 -- or --O--R.sub.4 --, where R.sub.4 is a C.sub.1 to C.sub.6 alkyl, the other of the groups F and G being a hydrogen atom and W being a hydrogen atom or a dimerizable group.

Abstract: The invention relates to a process for manufacturing a monomode cylindrical optical waveguide made of a polymer and endowed with electrooptic properties.According to the invention, the manufacturing process comprises the following steps:producing a cylindrical core rod (11) by polymerization of a mixture comprising a core polymer and an electrooptically active organic substance,forming a first preform (10 ) by coating the core rod (11) by means of an optical cladding (12) formed by a cladding polymer,fitting said first preform (10) into a first jacket (20) constituted by a jacket polymer,producing a second preform (30) by drawing the first jacket (20),fitting the second preform (30) into a second jacket (40) made of a jacket polymer,producing means (41, 42, 43, 44) for positioning electrodes for excitation of the active substance,fiber drawing the second jacket (40) until the core diameter (d.sub.