Abstract: The planar polarization transformer for a normally incident optical wave or beam having a given vacuum wavelength ? comprises an optical planar grating between a cover medium of refractive index nc and an optical substrate of refractive index ns, this planar grating defining a binary index modulation or corrugation of substantially rectangular profile with periodic ridges. This polarization transformer is characterized in that the ridge refractive index nr is larger than the substrate refractive index ns, the grating period ? is larger than 0.4·?/nc, the substrate refractive index ns is smaller than 2.7·nc, and the index modulation or corrugation is designed such that, according to the grating mode dispersion equation, the effective index of the mode TE0 is larger than the substrate index ns and the effective index of the mode TM0 is larger than the cover refractive index and smaller than the substrate index.

Abstract: The planar polarization transformer for a normally incident optical wave or beam having a given vacuum wavelength ? comprises an optical planar grating between a cover medium of refractive index nc and an optical substrate of refractive index ns, this planar grating defining a binary index modulation or corrugation of substantially rectangular profile with periodic ridges. This polarization transformer is characterized in that the ridge refractive index nr is larger than the substrate refractive index ns, the grating period ? is larger than 0.4·?/nc, the substrate refractive index ns is smaller than 2.7·nc, and the index modulation or corrugation is designed such that, according to the grating mode dispersion equation, the effective index of the mode TE0 is larger than the substrate index ns and the effective index of the mode TM0 is larger than the cover refractive index and smaller than the substrate index.

Abstract: A phase mask method to geometrically transform and to optically transfer a standard planar radial grating pattern into a cylindrical photoresist pattern at the circularly cylindrical wall of a given element. The planar radial grating pattern can be written with an integer number of lines having strictly constant period without any stitching problem. The photolithographic transfer is made by an illumination device providing a normal incident beam on the phase mask. The annular radial grating diffracts this normal incident beam, formed by plane waves, into two cylindrical waves of the first diffraction order (Tr+1 and Tr?1)) which impinge on the circularly cylindrical wall and interfere in a photoresist layer deposited on the circularly cylindrical wall to give rise to an interferogram.

Abstract: Disclosed is a Rotation sensor with a light source, a light detector, an internal part having a first lateral surface, which is globally cylindrical and convex, and an external part having a second lateral surface which is globally cylindrical and concave. The first and second lateral surfaces both have a same central axis defining a rotation axis for a relative rotation between the internal part and the external part the angle of which this rotation sensor can measure. A first grating is arranged at the first lateral surface with its grating lines parallel to the rotation axis, and a second grating is arranged at the second lateral surface with its grating lines parallel to said rotation axis.

Abstract: A polarizing mirror device including an optical substrate (1) of real refractive index ns; a dielectric multilayer mirror (2), composed of dielectric layers of low and high refractive index; and a corrugated grating layer (6) of local period ? at the side of a cover medium of refractive index nc.

Abstract: A polarizing mirror device including an optical substrate (1) of real refractive index ns; a dielectric multilayer mirror (2), composed of dielectric layers of low and high refractive index; and a corrugated grating layer (6) of local period ? at the side of a cover medium of refractive index nc.

Abstract: Disclosed is a Rotation sensor with a light source, a light detector, an internal part having a first lateral surface, which is globally cylindrical and convex, and an external part having a second lateral surface which is globally cylindrical and concave. The first and second lateral surfaces both have a same central axis defining a rotation axis for a relative rotation between the internal part and the external part the angle of which this rotation sensor can measure. A first grating is arranged at the first lateral surface with its grating lines parallel to the rotation axis, and a second grating is arranged at the second lateral surface with its grating lines parallel to said rotation axis.

Abstract: For increasing the power emitted by surface emitting lasers and for improving the spatial coherence of the laser beam, emitted in particular by disk lasers, microchip lasers and VCSELs having a relatively wide emitting area, the invention proposes to select a low order transverse cavity mode by means of a mirror structure (12) of high reflectivity, and of high angular selectivity. The mirror structure comprises a multilayer (14) receiving the optical beam (24) and a resonant grating mirror (16) following the multilayer and arranged for highly reflecting the optical beam in a narrow angular range at each side of a determined incidence angle.

Abstract: The invention relates to an information carrier (10), having a metal layer (40) with at least one track (14) in which marks (20) are disposed, which can be detected by means of light of a central wavelength (?) which is emitted by a light source (30) and which is incident upon the information carrier (10) at an angle (?i), and from which the position of the information carrier (10) can be derived, wherein the marks (20) are formed by areas (25) which are structured at least by first structures (22) of a lattice period (?) which are disposed on the back side (40b) of the metal layer (40) and/or on the front side (40a) of the metal layer (40), and wherein the lattice period (?) of the first structures (22) satisfies the equation ?=?/(np*?sin(?i)) or ?=?/(np*+sin(?i)), wherein ? is the central wavelength of the used light, ?i is the angle at which the light of the light source (30) is incident upon the information carrier (10) and np* is the effective index of a plasmon mode along the metal layer (40).

Abstract: For increasing the power emitted by surface emitting lasers and for improving the spatial coherence of the laser beam, emitted in particular by disk lasers, microchip lasers and VCSELs having a relatively wide emitting area, the invention proposes to select a low order transverse cavity mode by means of a mirror structure (12) of high reflectivity, and of high angular selectivity. The mirror structure comprises a multilayer (14) receiving the optical beam (24) and a resonant grating mirror (16) following the multilayer and arranged for highly reflecting the optical beam in a narrow angular range at each side of a determined incidence angle.

Abstract: The invention relates to an information carrier (10), having a metal layer (40) with at least one track (14) in which marks (20) are disposed, which can be detected by means of light of a central wavelength (?) which is emitted by a light source (30) and which is incident upon the information carrier (10) at an angle (?i), and from which the position of the information carrier (10) can be derived, wherein the marks (20) are formed by areas (25) which are structured at least by first structures (22) of a lattice period (?) which are disposed on the back side (40b) of the metal layer (40) and/or on the front side (40a) of the metal layer (40), and wherein the lattice period (?) of the first structures (22) satisfies the equation ?=?/(np*?sin(?i)) or ?=?/(np*+sin(?i)), wherein ? is the central wavelength of the used light, ?i is the angle at which the light of the light source (30) is incident upon the information carrier (10) and np* is the effective index of a plasmon mode along the metal layer (40).

Abstract: The invention relates to an optical device (2) for characterising a diffraction grating (14) which is formed by first and second interferometric diffractive sensors (4, 6) which are integral, spaced apart from each other at a determined first distance, and each comprise a reading grating (10a, 10b) and at least one light intensity detector, these first and second sensors providing respectively first and second electrical signals which, during a relative displacement (&Dgr;x) between the device and the diffraction grating, vary as a function of the spatial frequency of this grating in first and second regions of the latter, which regions are located respectively opposite two reading gratings and each receive light supplied by at least one light source. In particular, the first and second electrical signals define first and second phases of the first and second sensors.

Abstract: The invention concerns a light reflecting element comprising a substrate (10), a multilayer mirror (20) and optical coupling means (32, 40) comprising a diffraction grating (40); whereby the reflection coefficient of one polarization is damped without damping the reflection coefficient of the orthogonal polarization over a broad wavelength range and with a large tolerance on the optogeometrical parameters of the device.

Abstract: The optical electric current sensor is composed of a birefringent light guide (2) coiled around an electric current conductor (1) and is characterized by a spatial modulation of the magnetic field or of the birefringence of the light guide, along the light guide, at a spatial period equal to a whole number of times the beat length of the guide.

Abstract: A method of coupling an optical fiber to an optoelectronic component including a substrate having an optical waveguide therein, the waveguide opening into a notch formed in or on a first face of the substrate, including the steps of pre-positioning the optical fiber in a groove of an optical fiber support, the groove terminating at a first face of the optical fiber support, positioning the fiber support such that the first face of the substrate and the first face of the fiber support are directly opposite each other, the first faces forming a gap therebetween, and positioning an end of the optical fiber to be in the notch such that the waveguide and the optical fiber are optically aligned.

Abstract: An optical device utilizing white light interferometry, having a Fabry-Perot interferometer incorporated in a reference branch of the optical device. The succession of interference products occurs from a combination of the light traveling through the transmission branch with the light traveling through the reference branch which has undergone 0 to N+1 reflections in the Fabry-Perot interferometer. The interference product gives a series of equally spaced absolute marks.

Abstract: An optical sensor with intermodal interferometry, using a bimodal optical fiber propagating a first mode and giving rise to a second mode coupled to the first in response to a disturbance cause by a physical or chemical quantity of which it is wished to determine the position along the optical fiber by compensating the difference in the delay time between modes at the input of the interferometer.

Abstract: An optical waveguide force meter for the measurement of forces or stresses integrated on a single substrate, including: a single-mode transducer waveguide supporting only the stresses which are applied through the intermediate portion of an upper plate of the force meter; a coupling/mixing grating having N focussing concave gratings provided adjacent an exit end of the optical waveguide; N detectors arranged at each of the N focussing points of waves defracted by the coupling/mixing grating; N TM polarization filters arranged respectively between each concave grating and each detector; and a single-mode laser source. The waveguide, coupling/mixing grating and polarization filters are all provided on the single substrate. The single-mode laser source and detectors are supported by the substrate and by an underlying base plate member.

Abstract: The invention relates to an interferometric displacement measuring device in which the reference norm is a diffraction grid (G). Diffracted partial beam bundles (+m, -m) are fed into a coupler (TBJ) by means of coupling grids (+HG, -HG) via beam waveguides (+LWL, -LWL) and there brought into interference. The interfering partial beam bundles are transmitted from the outputs (+A, A, -A) via beam waveguides (+LWL, LWL, -LWL) to detectors (+D, D, -D) which convert them into electric signals out-of-phase with each other. The displacement of the diffraction grid (G) is a standard for measuring the changes in position of machine components which are movable relative to one another.

Abstract: Several photoelectric position measuring systems are described which utilize diffraction gratings to define the reference magnitude. Diffracted component beams are introduced by means of coupling-in gratings that have different grid constants from one another into optical waveguides to a coupler and there brought into interference. The interfering component beams are conducted from the outputs of the coupler via optical waveguides to detectors which transform them into electrical signals which are phase-shifted with respect to one another. Displacement of the diffraction grating is a measure for the position change to be measured of one machine component mounted for translation relative to another.