Abstract: A bifocal anastigmatic telescope with five aspherical mirrors, comprises: a concave first mirror, a convex second mirror, a concave third mirror and a first detector, which are common to a first and second focal length of the telescope, a first fourth mirror and a first fifth mirror that are associated with the first focal length, and a second fourth mirror and a second fifth mirror that are associated with the second focal length, the first mirror and the second mirror being arranged to form, from an object at infinity, an intermediate image situated between the second mirror and the third mirror, and for each focal length: the fixed positions and forms of the mirrors associated with the focal length being determined from the generalized Korsch equations with 5 mirrors, with the constraint of the first, second and third mirror and of the first focal plane that are common to the two focal lengths, and so as to optimize the image quality in the first focal plane of the telescope in accordance with a predetermi

Abstract: A bifocal anastigmatic telescope with five aspherical mirrors, comprises: a concave first mirror, a convex second mirror, a concave third mirror and a first detector, which are common to a first and second focal length of the telescope, a first fourth mirror and a first fifth mirror that are associated with the first focal length, and a second fourth mirror and a second fifth mirror that are associated with the second focal length, the first mirror and the second mirror being arranged to form, from an object at infinity, an intermediate image situated between the second mirror and the third mirror, and for each focal length: the fixed positions and forms of the mirrors associated with the focal length being determined from the generalized Korsch equations with 5 mirrors, with the constraint of the first, second and third mirror and of the first focal plane that are common to the two focal lengths, and so as to optimize the image quality in the first focal plane of the telescope in accordance with a predetermi

Abstract: The fibre is adapted to compensation of the chromatic dispersion and chromatic dispersion slope of an optical fibre with negative chromatic dispersion. It has, in a propagation mode other than the fundamental mode, a positive chromatic dispersion and a negative chromatic dispersion slope. The fibre can be used in compensation dispersion modules or as line fibre, in transmission systems using line fibre with negative chromatic dispersion.

Abstract: The fiber is adapted to compensation of the chromatic dispersion and chromatic dispersion slope of an optical fiber with negative chromatic dispersion. It has, in a propagation mode other than the fundamental mode, a positive chromatic dispersion and a negative chromatic dispersion slope. The fiber can be used in compensation dispersion modules or as line fiber, in transmission systems using line fiber with negative chromatic dispersion.

Abstract: The fibre is adapted to compensation of the chromatic dispersion and chromatic dispersion slope of an optical fibre with negative chromatic dispersion. It has, in a propagation mode other than the fundamental mode, a positive chromatic dispersion and a negative chromatic dispersion slope.