US Patent 7437040 Optical fiber with reduced stimulation Brillouin scattering

An optical fiber having a given refractive index profile comprises a core region and a cladding region. The core region includes at least two co-dopants and the concentration of at least one of said core dopant varies continuously over the entire core region. The optical fiber has, at a wavelength of 1550 nm, a spontaneous Brillouin spectrum width equal or larger to 100 MHz.