Patent ID: 7139457

Claim:
A method for compensating modal dispersion comprising coupling a mode dispersion-compensating fiber and a compensated fiber having refractive index profiles that satisfy the following equation: Δ comp ( r )=Δ opt ( r )+ k{Δ opt ( r )−Δ target ( r )} where Δ comp (r) is a relative refractive index difference of the mode dispersion-compensating fiber at a distance r from a core center, Δ target (r) is a relative refractive index difference of the compensated fiber at a distance r from a core center, Δ opt (r) is a relative refractive index difference of the entire fiber at the distance r from the core center when the compensated fiber and the mode dispersion-compensating fiber are coupled to obtain a maximum band at a predetermined wavelength, and k is a proportional numerical constant, wherein the mode dispersion-compensating fiber and compensated fiber comprise multimode optical fibers, modal dispersion is compensated in the compensated fiber, and the maximum band at the predetermined wavelength is obtained.