Abstract: The invention relates to an optical sample illumination device for a spectroscopic ellipsometer of the rotating analyzer type. The image of the exit slit (F') of a monochromator is conjugated with a point (F'.sub.2) of a surface of a sample (E) by means of two spherical mirrors (M.sub.7 and M.sub.8). An astigmatism correction slit (F'.sub.15) is arranged in the proximity of the conjugate (F'.sub.1) of the exit slit(F') of the monochromator with respect to the spherical mirror (M.sub.7) and is arranged perpendicularly to this exit slit and to the optical path so that said correction slit is conjugated with the said point (F'.sub.2) through the spherical mirror (M.sub.8). A luminous spot without astigmatic errors is thus obtained.

Abstract: Optical viewing or projection device, comprising at least two objectives (L.sub.1 L.sub.2) whose optical axes (x.sub.1 x'.sub.1 ; x.sub.2 x'.sub.2) are parallel to a general axis of symmetry (xx') of the device, endowed with a focusing system permitting the formation of images or viewing in a fixed reference plane (P'.sub.0), by means of simultaneous translation of the objectives in parallel to the general axis of symmetry, and comprising means for reducing the parallax produced by the objectives, the means for reducing the parallax including a system of parallel-faced plates (M.sub.1 M.sub.2) which has the general axis of symmetry (xx') of the optical device as its axis of symmetry, wherein a parallel-faced plate is placed between each objective (L.sub.1, L.sub.2) and the fixed reference plane (P'.sub.

Abstract: An optical coupling device for coupling a first optical waveguide having an end face and transmitting a number N of signals of different wavelengths with a number N of further optical waveguides having end faces and each transmitting one of these signals comprises means for the spectral selection of these signals, which means include a wavelength separator with interference filters, and means for the spatial selection of these signals in order to achieve this coupling.

Abstract: A device for coupling a light source and an optical waveguide. The light source has an emissive surface whose dimensions are of the same order of magnitude as or smaller than the cross-sectional dimension of the waveguide. The coupling device comprises a ball lens, which is contact with the light source, and a convergent optical transfer system. The optical transfer system images the input face of the waveguide to the optical center of the ball lens with a magnification of approximately -1. The radiation issuing from any point of the emissive surface of the light source enters the waveguide as parallel rays.