Patent ID: 7242870

Claim:
A wavelength division multiplexing system comprising: a wavelength division multiplexing transmission path comprising a multimode optical fiber that comprises a core and a cladding and is codoped with germanium and fluorine, wherein the multimode optical fiber provides an overfilled-launch bandwidth of 1.5 GHz·km or higher for a signal transmitted therethrough at any wavelength between approximately 720 nm and approximately 1400 nm, and the multimode optical fiber has a refractive index profile as follows: n ⁡ ( r ) = { n 1 ⁡ [ 1 - 2 ⁢ ⁢ Δ ⁡ ( r a ) a ] 1 / 2 ( 0 ≤ r ≤ a ) n 1 ⁡ ( 1 - 2 ⁢ ⁢ Δ ) 1 / 2 ( r > a ) where n(r) is a refractive index of the optical fiber at a distance “r” from a center of the core, n 1 is a refractive index at a center of the core, Δ is a relative refractive index difference of the center of the core with respect to the cladding, “a” is a core radius, and α is a refractive index profile exponential parameter, and Δ is Δ 1 +Δ 2 , and Δ 1 /Δ 2 is between 1/1 and 0/1 or Δ 1 /Δ 2 is ¼ (where Δ 1 is a relative refractive index difference of germanium with respect to the cladding and Δ 2 is a relative refractive index difference of fluorine with respect to the cladding).