Patent ID: 8520993

Claim:
A multimode optical fiber, comprising: a central core positioned within an outer optical cladding, said central core having a radius r 1 and an alpha refractive index profile with respect to said outer optical cladding; an inner cladding positioned between said central core and said outer optical cladding, said inner cladding having a radius r 2 and a refractive index difference Δn 2 with said outer optical cladding; a depressed trench positioned between said inner cladding and said outer optical cladding, said depressed trench having a width W t and a refractive index difference Δn t with said outer optical cladding; wherein, at said central core's radius r 1 , the refractive index difference between said central core and said outer optical cladding is zero; wherein said depressed trench's refractive index difference Δn t is between about −7×10 −3 and −10×10 −3 ; wherein said depressed trench's width W t is between 3 microns and 4.5 microns; and wherein said depressed trench has a volume V of between about −30 microns and −40 microns as defined by the expression V=1000×W t ×Δn t .