Abstract: The invention relates to optical waveguide components, such as Faraday rotators and their manufacture Faraday rotators based on silicon waveguides are provided, where the waveguide has folded or wound sections that are parallel to an externally applied magnetic field.

Abstract: The invention relates to optical waveguide components, such as Faraday rotators and their manufacture Faraday rotators based on silicon waveguides are provided, where the waveguide has folded or wound sections that are parallel to an externally applied magnetic field.

Abstract: To identify an embossed image of a coin in an automatic coin machine, the coin requiring identification is moved past an image receiver and a light source, the light source having at least two lighting portions which illuminate an object field of the coin requiring identification from different directions under the same angle with respect to the surface normal of the object field and with wavelength ranges which do not overlap each other. An image receiver records one picked-up exposure of the object field from which images are obtained for each of the individual lighting portions of the individual wavelength ranges. A maximum image is then determined from the images, wherein each pixel has associated therewith the maximal intensity value from the images of the individual wavelength ranges. A genuine-coin or counterfeit-coin signal is determined from the maximum image.

Abstract: A process for identifying an embossed image of a coin in an automatic coin tester, in which a coin is moved to an image receiver and a light source, the image receiver picks up at least one image of the embossed image of the coin, and a validation device compares the image to a first reference pattern to find out whether the first reference pattern is contained in the image which was picked-up. If the first reference pattern is contained in the image, the validation device determines whether a second reference pattern is contained in an area the position of which is determined relative to the position of the first reference pattern, the validation device producing a genuine coin or counterfeit coin signal for the coin depending on the coincidence of the image with the reference patterns.

Abstract: To identify an embossed image of a coin in an automatic coin machine, the coin requiring identification is moved past an image receiver and a light source, the light source having at least two lighting portions which illuminate an object field of the coin requiring identification from different directions under the same angle with respect to the surface normal of the object field and with wavelength ranges which do not overlap each other. An image receiver records one picked-up exposure of the object field from which images are obtained for each of the individual lighting portions of the individual wavelength ranges. A maximum image is then determined from the images, wherein each pixel has associated therewith the maximal intensity value from the images of the individual wavelength ranges. A genuine-coin or counterfeit-coin signal is determined from the maximum image.

Abstract: A process for identifying an embossed image of a coin in an automatic coin tester, comprising the process steps below: The coin is moved to an image receiver and a light source, the image receiver picks up at least one image of the embossed image of the coin, an validation device compares the image to a first reference pattern to find out whether the first reference pattern is contained in the image which was picked up, if the first reference pattern is contained in the image the validation device determines whether a second reference pattern is contained in an area the position of which is determined relative to the position of the first reference pattern, the validation device produces a genuine coin or counterfeit coin signal for the coin depending on the coincidence of the image with the reference patterns.

Abstract: A method for mechanically stabilizing and for tuning a filter having a photonic crystal structureThe cavities of the filter fabricated as a photonic crystal structure are filled with optically transparent material having an adjustable refractive index. The optical properties of the filter and, thus, the filtering action are adjusted by way of an electric field having a variable field strength.It is possible to produce small-dimensioned, narrow-band filter elements, which are finely tunable and tunable within a broad range, and to realize them as filter elements which are integrated with a high packaging density.

Abstract: A copolymer based on monomers selected from the group consisting of dicarboximides, alkenyl isocyanates and alkenylurethanes of formula I: ##STR1## where R.sup.1 to R.sup.5, R.sup.6, X, Y, Z, M, and a-d are as defined in the specification.

Abstract: A device for reversible optical information storage with a polymeric liquid crystalline storage medium, with the storage medium consisting of a macroscopically oriented film of a liquid crystalline polymer that contains photochromic groups, and with the information being stored by local disorientation of the molecules induced by photoisomerization by means of a selectively acting light source.

Abstract: A device for reversible optical data storage, comprising polymer film, the film comprising an amorphous polymer capable of photochromic isomerization, whereby data is reversibly stored in said polymer film and may be read by illuminating the isomerized polymer film with a light source.

Abstract: The invention relates to an apparatus for reversible optical data storage using polymeric liquid crystals with mesogenic side groups as a storage medium, arranged to store information by means of selective variation of the order of the polymeric liquid crystals be means of a heat source. The macroscopically oriented film made from the liquid crystal polymer is held in the solid form retaining condition of the liquid crystal polymer in the temperature range below the glass temperature T.sub.g >T.sub.a (room remperature) for the purpose of storing the information. The polymer is then selectively and locally heated by means of the heat source into the isotropic liquid condition and the local information is fixed in the glass condition of the polymer after the heat source is turned off.

Abstract: The invention relates to a device for reversible optical information storage, which comprises polymeric liquid crystals as a storage medium. The device contains a film comprised of a liquid crystal main chain polymer, as a storage medium, and is constructed so that in the storage operation the storage medium is locally reoriented, and the information is stored by means of a local variation of the molecular ordering.

Abstract: The invention concerns a process for reversible optical information storage by means of a liquid crystal storage medium, whereby the information is stored in a firm of a liquid crystal side chain polymer in an anisotropic phase by means of locally acting heat source in combination with an electric, magnetic or surfaces active field, through local reorientation.