Broad bandwidth multimode optical fiber with low bending losses

摘要

The present invention relates to an optical fiber, comprising from the center towards the periphery, a central core; an inner cladding surrounding the central core; a buried trench surrounding the inner cladding; and an outer optical cladding. The central core presents an alpha refractive index profile and a matrix that is doped at least with fluorine and with an element that increases refractive index. The atomic ratio between the fluorine and all of the constituents of the doped matrix of the central core increases from the center of the fiber to the end of the alpha profile of the central core to reach a maximum value lying in the range 8.5x10 -3 to 57x10 -3 at the end of the alpha profile of the central core. The buried trench presents a width w 3 lying in the range 2 µm to 10 µm, and a refractive index difference ”n 3 relative to the outer optical cladding lying in the range -15x10 -3 to -6x10 -3 .