Patent ID: 8867880

Claim:
A multimode optical fiber, comprising: a central core having an alpha-index profile with a radius (r 1 ); and a depressed trench surrounding the central core, the depressed trench having a width (w t ) and a refractive index difference (Δn t ) with respect to an outer optical cladding; wherein the depressed trench's width (w t ) is between about 0.5 micron and 2 microns; wherein the depressed trench's refractive index difference (Δn t ) with respect to the outer optical cladding is substantially constant over the entire width (w t ) of the depressed trench and is between about −4×10 ˜3 and −1×10 −3 ; wherein the central core's diameter (2·r 1 ) is between about 47 and 53 microns; wherein the central core has a maximum refractive index difference (Δn 1 ) with respect to the outer optical cladding of between about 11×10 −3 and 16×10 −3 ; wherein the refractive index difference between the central core's alpha-index profile at the radius r 1 and the outer optical cladding is negative and greater than Δn t .