Abstract: An optic fiber wavelength multiplexer-demultiplexer comprising a dispersing system (1) exhibiting a dispersing plane, at least one input fiber (2) with an output face, at least one output fiber (3) with an input face, and a device (4) for optic matching of the output face of the input fiber with the input face of the output fiber. The dispersing system and the matching means form an optic system with multiple transversal focuses (6) in the dispersing plane.

Abstract: A multiplexer, demultiplexer or router includes an input fiber and an output fiber, each fiber having a core and a sheath. At least one of the input fiber and the output fiber includes an intermediate ring having an optic index greater than the optic indexes of immediately adjacent portions of the core and the optic sheath and less than the optic index of the center axis of the core.

Abstract: A wavelength selective optical device includes a two-dimensional grating (6) and a device 11. The two-dimensional grating represents an intrinsic function. The device (11) is to change the complex amplitude of the electromagnetic field of the light wave, according to a filtering function, and is to expand the image spot into a monochromatic light in the direction of the spectral dispersion. An optical fiber wavelength multiplexer-demultiplexer includes a filter (11), a mirror (9) and a grating (6). The optical axis of the mirror passes through the plane of the grating and is parallel to the lines of the grating. The filter (11) is arranged in the vicinity of the mirror to control the intrinsic function of the multiplexer-demultiplexer.

Abstract: A modified concentric spectrograph for diffracting light with high stray light rejection without astigmatism is provided. The modified spectrograph includes a grating, a lens, and at least one entrance port and one exit port. The grating has a concave surface and a meridian plane with a first side and a second side. The lens has a substantially planar surface and a convex surface. Preferably, the convex and concave surfaces are substantially concentric. The ports are substantially located on different sides of the meridian plane near a focal plane of the spectrograph. The position of a focal plane may be modified using an optically transmissive triangular prism with a reflective surface, and an optically transmissive block. The position of a focal plane may further be modified with one or more optically transmissive plates. Methods for using the spectrograph are also provided.

Abstract: An optic dispersing system, designed for usage in a wavelength field of a beam, includes a network or grating (1) carried by a support (2) with a dilatation coefficient .epsilon.. The system suggested is temperature-stabilized. To do so, it contains a front blade or optical element (3), or refractive index n.sub.1, transparent in the concerned wavelength field. .epsilon.+1/n.sub.1 .times.dn.sub.1 /dt is small and, advantageously, dn.sub.1 /dt and .epsilon. are of opposite signs. This device enables the manufacture of a multiplexer-demultiplexer or a fiber optic wavelength router, which is temperature-stabilized.

Abstract: An intra-ocular ball for constituting a prosthesis after enucleation or evisceration of an eye is made of porous sintered alumina having interconnected pores with a diameter of about 300 microns, and capable of receiving a driver after colonization.

Abstract: A system for introducing a liquid sample (1) for analytical atomic spectrometry includes a nebulizer (20) and separator (27) at the exit (23) of the nebulizer. The system also includes at least one drain (30) fitted with evacuator (16, 17) for evacuating residual liquid (8) in a constricted and controlled flow, and reagent supplier (12, 13) for supplying drain (30) with a reagent (2) to generate hydride.

Abstract: Device and method for three-dimensional measurements and observation of a surface layer of a thin-film structure, comprising a monitoring unit 4 which includes a video camera 12, a wide-beam illumination source 14, a narrow-beam illumination source, 20, an operation and control unit and a table for horizontal movement. The device comprises a Wollaston prism 24 arranged on the optical path of the narrow light beam, in order to obtain two narrow light beams whose polarization states are linear and mutually orthogonal, a polarizer 27 arranged on the optical axis of the Wollaston prism 24 so that the reflected narrow light beam passes through it after its travel through the Wollaston prism 24, and a detection cell 28.

Abstract: A photodetection system that analyzes a luminous flux (15) received on a line (10). The photodetection system includes an opaque mask (4) provided with at least one aperture (6), placed in the vicinity of the line, driver (7) designed to rotate the mask, detector (8, 9) of an angular position of reference of the mask, a field lens (12) concentrating the luminous flux (16) crossing the line onto a photodetector (1), and a processing unit (3) connected to the photodetector, for analyzing the luminous flux to yield values for several points on the line.

Abstract: An N.times.N wavelength router (1) includes n m.times.m couplers (10, 15, 20, 25), N being equal to n.times.m, and the N inputs (11, 12, 16, 17, 21, 22, 26, 27) of the couplers being the inputs (E1-E8) of the N.times.N router. The N.times.N router also includes m n.times.n routers (30, 40) capable of switching an optical signal having a wavelength, from any one of its n inputs (31-34, 41-44) to any one of its n outputs (35-38, 45-48), according to the wavelength of the signal. The inputs of the n.times.n routers are connected to the outputs of the m.times.m couplers, and the outputs of the n.times.n routers are the outputs (S1-S8) of the N.times.N routers. The transmission spectra of the n.times.n routers have the form of a series of peaks, each of the series being different one from another.

Abstract: The present invention relates to a multiplexer-demultiplexer for optical wavelengths comprising:endpoints of input-output lines (22.sub.1, 22.sub.2, . . . ,22.sub.n),an endpoint of a transmission line (23),a diffraction network with a diffraction plane and,an optical system ensuring the optical conjugation between the input-output lines (22.sub.1, 22.sub.2, . . . ,22.sub.n) and the endpoint of the transmission line (23),The endpoints of the input-output lines (22.sub.1, 22.sub.2, . . . ,22.sub.n) are aligned along a straight line parallel to the diffraction plane and the endpoint of the transmission line (23) is offset transversally with respect to said straight line.

Abstract: A grating drive apparatus for use in a multiple-grating spectrometer is provided. The spectrometer has an entrance slit, an exit port, an optical path between the entrance slit and the exit port, and a plurality of diffraction gratings. Each of the gratings is rotatable about a respective preferred axis for selecting a wavelength during spectrometer operation. The grating drive apparatus includes a turret having a plurality of gratings mounted on it, a mechanical stop assembly, and a drive assembly. The drive assembly causes the turret to engage the stop assembly to rotate the turret and select a grating. The drive assembly also rotates the selected grating to select an operational wavelength.

Abstract: An instrument for boring dental radicular canals in which the conicity of the active part of the tapered stem of the instrument is not constant but the angle of its opening is greater at its rear portion, positioned beyond the diameter D.sub.9, than the angle of opening of its front portion positioned between its end and the diameter D.sub.9 so that a dental canal bored with the instrument has a bell-mouthed shape.

Abstract: The length of the active part of each drill of the set is inversely proportional to the diameter of the cutting edge of each drill, that prevents the drills of the set being too much engaged in the coronary canal, since the depth of the working depends with precision from the used drill.

Abstract: A luminous flux measuring device has a gain slaving circuit (10, 9), that receives an electrical output signal (m) produced by a photoreceiver (1) and includes a gain control circuit (9) and a comparator (10). The gain slaving circuit is connected to an A/D converter and a computer to record and evaluate the signal (m) and has a slave memory containing characteristic values (a,b) of a continuous function (f). The gain slaving circuit produces a slave signal (HT) according to the flux received (.PHI.) by the photoreceiver which signal is sent to the gain control circuit so that G=f(m).

Abstract: The central part of the instruments of the boring set, prior to the portion having the cutting edges, has a section of a polygonal shape. The lateral faces of the central part are either convex, for the instruments of small diameter, plane for the instruments of middle diameter and concave for the instruments of largest diameter, in such a way that the curve of the bending moments of the instruments of the set is substantially rectilinear. Thus the variation of the bending moments of the instruments is linear, while, in previously known sets of instruments, the curve is exponential. Hence, the flexibility of the instruments of the set is satisfactory for the entire set of instruments, while; in the known conventional sets, if previously flexibility of the small instruments of the set is satisfactory, the instruments of largest diameter will be too rigid, and vice versa.

Abstract: A set of instruments for boring of radicular dental canals, in which the diameter D1 of each instrument, measured at the root of the pointed end portion thereof, varies according to a geometrical progression as well as the diameter D2 of each instrument measured at the root of the cutting edges. Hence, the variation is more pronounced for the diameters D2, larger than the diameters D1, than it is for the diameters D1. The conicity of the stem of the instruments increases in this manner from one instrument to another, so as to permit a the dentist to form the radicular canals with a specially funnelled shape which is best suited for some obturations, especially those to be treated with gutta-percha.

Abstract: This invention relates to a method and a device for the ellipsometric measurement of physical parameters representative of a sample.The measured values I.sub.om, I.sub.sm and I.sub.cm are calculated (51, 52) from the signal (50) which represents the measured intensity I(t).In a first step (55, 57), initial theoretical values I.sub.st /I.sub.ot and I.sub.ct /I.sub.ot are produced from initial estimations (56) of the physical parameters. In a second step (58, 59) subsequent estimations (59) of physical parameters are determined from which subsequent theoretical values I.sub.st /I.sub.ot and I.sub.ct /I.sub.ot are deduced (55, 57). The second step is reiterated to an Nth estimation (59) of the physical parameters, so as to minimise the difference between the theoretical values and those measured.The physical parameters are evaluated (54) in the course of the Nth estimation.

Abstract: A set of instruments for boring dental radicular canals in which the conicity of the rear part of the set positioned beyond the diameter D.sub.9 of the instruments, increases more for the first instruments of the set than for the last ones. The conicity of the front part of the instruments does not increase much for the first instruments of the set, but does increase for the last ones. Hence, while using successively the instruments of a set, the dentist bores first the coronary portion of the tooth, then its medium portion and then its apical portion. The end part of the instruments, between the point thereof and their diameter D.sub.3, situated at 3 mm from the point, is provided with one or several grooves for elimination of the dental scraps, but which have no cutting edges so that this part of the instruments functions only for their guidance.

Abstract: A positioning stud for master models, formed by a cylindrical body, in which approximately one third of its length is threaded, this threaded area being separated from the rest which is smooth, by a circular boss, to limit the threaded area being inserted in the master model concerned. The free end of the stud is adequately shaped to fit the auxiliary tool used to place it in the model.