Patent ID: 8391661

Claim:
A multimode optical fiber, comprising: a central core surrounded by an outer optical cladding, said central core having (i) an outer radius a, (ii) a transition radius r t that is less than the outer radius a, (iii) a maximum refractive index n 0 , (iv) a minimum refractive index n c1 , and (v) a graded-index profile n(r) that is a function of the radial distance r from the center of said central core; wherein said central core's graded-index profile n(r) is defined by the following equation: n ⁡ ( r ) = n 0 ⁢ 1 - 2 ⁢ Δ ⁡ ( r a ) α ⁡ ( r ) where: Δ = ( n 0 2 - n cl 2 ) 2 ⁢ n 0 2 wherein Δ is about 1.9 percent or greater; wherein the alpha parameter α(r) is a function of the radial distance r from the center of said central core, said alpha parameter α(r) having two or more different values along radial positions from said central core's center to said central core's outer radius a; wherein, for a radial position less than said central core's transition radius r t , the alpha parameter α(r) has a first alpha-value α 1 ; wherein, for a radial position greater than said central core's transition radius r t , the alpha parameter α(r) has a second alpha-value α 2 ; wherein the first alpha-value α 1 is greater than the second alpha-value α 2 ; and wherein said central core's graded-index profile n(r) and the graded-index profile's first derivative dn(r)/dr are substantially continuous along radial positions from said central core's center to said central core's outer radius a.