Patent ID: 9709732
Date: 2017-07-18
CPC Classifications: G02B

Claim:
1. A broadband multimode optical fiber comprising: a core region having a transverse cross-section and a longitudinal axis, said core region being configured for broadband operation at wavelengths λ within a predetermined wavelength range, Λ, and a cladding region surrounding said core region, said core and cladding regions being configured to support the propagation of optical radiation in said core region and along said axis simultaneously in a plurality of transverse modes, said core region being co-doped with a plurality of dopants, the concentrations and distributions of said dopants being radially varied within said transverse cross-section of said core region so that the refractive index of said core region is radially graded and so that variations in z(r, λ) with respect to wavelength are reduced, where r is radius, λ is the wavelength of said optical radiation, n is the refractive index of said core region, k 0 =2π/λ is the wave number, and wherein said concentrations and distribution of said dopants are also radially varied within said transverse cross-section of said core region so that where z cl (λ) is z of said cladding region, and ∈ 1 is a tolerance factor that is chosen such that said fiber has a desired transmission and bandwidth performance within said operating wavelength range, λ.