OPTICAL DEVICE COMPRISING A TAPERED OPTICAL FIBRE AND USE OF SUCH A DEVICE FOR INJECTING A WAVE INTO A DOUBLE-CLAD FIBRE AND FOR EXPANDING A WAVE OUTPUT BY A FIBRE

The invention relates to an optical device comprising a microstructed tapered first optical fibre (1) bonded to a microstructured double-clad optical fibre (8). The tapered first optical fibre (1) has a single multimode central core (5) surrounded by a cladding (6). The double-clad optical fibre has a tubular multimode peripheral core (12) in which there is a single-mode central core (11). The multimode peripheral core (12) is surrounded by a second cladding. The tapered first optical fibre serves to focus the light that enters the double-clad optical fibre. Furthermore, the tapered first optical fibre serves to expand a light beam emanating from the double-clad optical fibre. L' invention concerne un dispositif optique comportant une première fibre optique effilée (1) microstructurée accolée à une fibre optique double gaine (8) microstructurée. La première fibre optique effilée (1) comporte un seul coeur central multimode (5) entouré par une gaine (6). La fibre optique double gaine comporte un coeur périphérique multimode (12) tubulaire dans lequel se trouve un coeur central monomode (11). Le coeur périphérique multimode (12) est entouré d'une deuxième gaine. La première fibre optique effilée permet de focaliser la lumière qui entre dans la fibre optique double gaine. En outre, la première fibre optique effilée permet l'expansion d'un faisceau lumineux qui sort de la fibre optique double gaine.