Abstract: A method is provided for manufacturing an electrooptic cell, which includes two plates of optically transparent material and at least one thickness of a composite gel based on a smectic liquid crystal and on a polymer provided between the plates, wherein the gel is in a smectic phase at ambient temperature. The method includes injecting a mixture of a ferroelectric and/or anti-ferroelectric smectic liquid and a monomer between the plates, wherein the monomer content of the mixture is between 5 and 25% by weight. The mixture is heated to above its smectic phase/nematic phase transmission temperature so that the mixture is in the nematic phase. The mixture is irradiated, by ultraviolet radiation, so as to polymerize the monomer and thus obtain the gel. During the irradiation step, an electric or magnetic field is applied to the mixture.

Abstract: An optical refractometer is provided for measuring the refractive index of a liquid. Such a refractometer includes a first optical block having a transparent material whereto is secured a light source, a second optical block having a transparent material whereto is secured a position sensor. The optical blocks are arranged on either side of a conduit wherein the liquid flows.

Abstract: This invention relates to a vertical cavity surface emitting laser (VCSEL) comprising at least one optical element inside the said cavity, the optical element having a variable optical loss profile (44) in a plane perpendicular to an axis of propagation of at least one light beam passing through the said cavity so as to encourage transverse mode of the said laser.

Abstract: The invention relates to a spatial phase filter capable of receiving an incident light beam so as to transmit it to a single mode output fibre comprising a spatially variable phase profile and being adapted to excite the evanescent modes of the output fibre. The profile has: an adjustable pattern with a phase distribution substantially corresponding to a combination of at least one quantile of normal distribution on at least one dimension (301); and a phase shifting zone support (320) limited in relation to the incident beam according to the dimension(s). The invention also relates to a system implementing several filters and a method for filter calculating.

Abstract: The invention relates to a device for spatial modulation of a light beam of the type including: a polymer dispersed liquid crystal (PDLC) element, comprising at least two pixels distributed in a matrix with two pixelisation axes and that can be addressed independently of each other using a system with at least two electrodes; optical means for reducing the sensitivity of the said device to polarisation of the incident light beam. According to the invention, the optical means comprise depolarisation means for depolarising the incident light beam on the said PDLC element.

Abstract: This invention relates to a compound based on liquid crystals for making optoelectronic components. According to the invention, this compound comprises at least one cyanoester, at least one isothiocyanobiphenyl and at least one monomer.

Abstract: This invention relates to an optical equalisation device (312) of at least one incident optical beam (40) separated in wavelength into several channels or spectral bands called demultiplexed optical beam, the device including at least two independently controllable cells (420, 430, 440) each comprising spatial phase modulation means and means of scattering the incident optical beam(s). The device is adapted such that at least one of the demultiplexed beams (312) simultaneously and approximately illuminates at least two of the cells (420, 430, 440). The invention also relates to a corresponding system.

Abstract: The invention relates to an interferometric system (2) for selection of spectral components of an incident optical beam as a function of their wavelength, comprising: means (42) of transforming the said incident optical beam into two spatially demultiplexed beams; means (43) of shifting the phase of at least one of the said spatially demultiplexed beams, the phase shift being applied spatially so as to produce two so-called phase shifted beams, the phase of at least one of their components being shifted as a function of its wavelength; means (44, 42) of recombining the said phase shifted beams adapted to produce a first and a second output beam, each of the said output beams being multiplexed in wavelength and comprising components of the said phase shifted beams, selected as a function of a first and a second phase shift respectively.

Abstract: The invention relates to a dynamic spectral equaliser comprising: means of demultiplexing an incident beam with at least two multiplexed wavelengths, comprising at least one first dispersive optical element, so as to form a spatial multiplex of the said at least two wavelengths; means of attenuating the spectral power associated with at least one wavelength of the said spatial multiplex, comprising at least one programmable semi-transparent holographic mirror, so as to form an equalised spatial multiplex; means of multiplexing the said equalised spatial multiplex, comprising at least one second dispersive optical element, so as to form an equalised beam with at least two multiplexed wavelengths.

Abstract: The invention concerns a device for controlling the polarization of a signal transported, by optical fiber, in the form of a luminous beam. According to the invention, this device comprises: a cell formed by two substrate plates essentially parallel to one another and between which is confined a contents comprising a polymer in which droplets of liquid crystal are dispersed; first application means, on at least part of the cell contents, of an electrical field more or less perpendicular to the direction of the spread of the luminous beam. so that, depending on whether the first electrical field is applied or not, at least part of the contents of the cell forms a birefringent or isotropic medium respectively.

Abstract: The invention relates to a resonant cavity enhanced photodetector (10, 60) comprising a first (20) and a second (21) reflection means forming the said cavity and means of absorption (22) of photons of an incident light beam (17), characterised in that it also comprises at least one electro-optical element inside the said cavity, intended for tuning the wavelength of the said photodetector. The invention also relates to a matrix of several photodetectors and a corresponding telecommunication system.

Abstract: This invention relates to a device for spatial modulation of a light beam, comprising a Polymer Dispersed Liquid Crystal (PDLC) element, the said element comprising at least two areas that can be addressed independently of each other using a system with at least two electrodes.

Abstract: The invention concerns a tuneable vertical cavity laser amplifier, comprising, inside the cavity (25) at least an electro-optical element designed to tune the wavelength (&lgr;) of the laser amplifier, at least one of the electro-optical elements including an isotropic material in a transverse plane. The invention also concerns a telecommunication system comprising the tuneable laser amplifier, an array comprising a plurality of laser amplifier and a method for making same.

Abstract: A spatial light modulator (SLM) is made up of a cell filled with a liquid crystal (LC) based substance. Latter has a variable scattering property with respect to an electric field present in the cell. By using a plurality of electrodes in the direct vicinity of said cell, it is then possible to build an electric field inside it which will permit advantageously to modulate a continuous spectrum from optical signals transmitted through said cell. The different pass bands present in said continuous spectrum while at least few of them comprise at least a respective different wavelength will have to be transmitted through said cell at different regions. Latter will correspond to different values of the amplitude of scattering such to be adapted to modulate the respective different pass bands. Such SLM is used to build a dynamic spectral equalizer. Latter contains a spectral dispersive element placed on an optical path of an incident light beam.

Abstract: An attenuation device for a signal carried by an optical fiber in the form of a light signal is manufactured. The optical cores of a first and a second single-mode fiber are expanded. The first and second fibers are assembled facing each other in a capillary containing a liquid crystal. The liquid crystal is polymerized to produce an attenuation element. The resulting attenuation device comprises a first and a second single-mode fiber with expanded optical cores assembled facing each other in a capillary containing a liquid crystal forming attenuation means.

Abstract: A spatial light modulator (SLM) is made up of a cell filled with a liquid crystal (LC) based substance. Latter has a variable scattering property with respect to an electric field present in the cell. By using a plurality of electrodes in the direct vicinity of said cell, it is then possible to build an electric field inside it which will permit advantageously to modulate a continuous spectrum from optical signals transmitted through said cell. The different pass bands present in said continuous spectrum while at least few of them comprise at least a respective different wavelength will have to be transmitted through said cell at different regions. Latter will correspond to different values of the amplitude of scattering such to be adapted to modulate the respective different pass bands. Such SLM is used to build a dynamic spectral equalizer. Latter contains a spectral dispersive element placed on an optical path of an incident light beam.

Abstract: Connection device for multiple-core optical fibers based on optical elements in free space. This device comprises a first optical means (36) which is refractive or diffractive, and at least one second means (38, 40) which is diffractive. The first means causes the light beams exiting cores (30) of fiber (28) to diverge as far as an area in which these beams are separated in space and have cross sections whose size is compatible with the spatial bandpass of the second means. The latter is positioned in this area and directs the beams, independently from one another, towards corresponding optical components (34). Application to optic telecommunications.

Abstract: The modulator is formed by a smectic chiral ferroelectric C* liquid crystal cell (CL), crossed by the light signal which is transmitted by the said fibre. The cell (CL) is provided with transparent walls and transparent command electrodes (5 to 7). The liquid crystal (CL), used in half-wave mode, is of the SSFLC (surface stabilized ferroelectric liquid crystal) type, having a wide tile angle .theta., which is as close as possible to 45.degree., in such a way that the said modulator is insensitive to polarisation. The modulator may be connected to two parallel fibres (A2, A3; B2, B3), pertaining to the intermediary part of a Mach-Zehnder coupler between the two 3 dB couplers, and when it is provided in order to modulate the light signal transmitted by either one of the two fibres.

Abstract: Light diffraction device using reconfigurable spatial light modulators and the fractional Talbot effect. This device comprises two liquid crystal, electrically addressable spatial light modulators (M1, M2) on a semiconductor substrate and at least one polarizing beam splitter (2), the optical path between the modulators being equal to (2k+1) Z.sub.T /4.sup.n in which k and n are natural integers, n differing from zero, and Z.sub.T is the Talbot distance relative to a biperiodic hologram obtained by means of one of the modulators and at one of the periods equal to double the other, which makes it possible to obtain a reconfigurable hologram having four phase levels. Application to optical telecommunications.