Abstract: A long-interval grating in an optical fiber is designed to enable the making of a mode-coupling filter. In particular, it has periodic variations of the diameter of the optical fiber and a symmetry of revolution.

Abstract: A photo-imprinting stand for the making of Bragg networks on a photosensitive waveguide or on optical fibers is used to obtain an apodization of the grating. The stand has a dynamic masking device having a variable surface with respect to the beam of UV rays during the photo-imprinting carried out by insolation of the guide using a beam of ultra-violet rays and an interferometry device. Application to the apodization of Bragg gratings.

Abstract: A method for the controlled stretching of one or more optical fibers according to a desired profile and a device for its implementation. The method includes several steps. In these steps, a speed V.sub.e =dx.sub.e /dt of flow of the fiber entering the heating chamber is laid down, a relationship f of variation of the diameter D.sub.s of the fiber during exit from the heating chamber is chosen such that D.sub.s =f(x.sub.s) wherein x.sub.s represents the positions, variable in time, of a point on the fiber during exit from the heating chamber, successive stretching operations are performed on the fiber to modify, each time, the diameter D.sub.s of the fiber during exit from the heating chamber, so as to follow the profile defined by the relationship f of variation. The method has application to the making of optic fiber devices.

Abstract: The device comprises a first optical means focusing the beam whilst forming therefrom an elongated focal spot and a second optical means facing the first and giving an image spot of the focal spot which is substantially parallel and facing said focal spot. The machine comprises a light source able to heat the ends of the fibres, means for the positioning and holding of said ends against one another, as well as the device, said ends being placed between the spots.

Abstract: An electro-optical light wave modulator is a waveguide constituted by a thin electro-optic material layer on which conductive clads are deposited and supported by a substrate. The refractive index of the thin layer is larger than that of air and that of the substrate material, so that vertical guiding is inherently ensured.The conductive clads form a divergent arrangement which opens towards a light input. At the device inlet, the distance between the conductive clads is large enough for guiding one or several light wave modes. At the device outlet, the corresponding distance is too small for guiding any mode when no difference of voltage is applied to the clads. When the voltage difference between the two clads reaches a certain value, the resulting electric field enable the device outlet to guide one or several modes, depending on such a voltage value. By varying the voltage difference, it is possible to modulate light which is outgoing from the device outlet.