Patent ID: 7437040

Claim:
An optical fiber comprising: a core region having a given refractive index profile and including at least two codopants; a cladding region having a given refractive index profile; wherein the concentration of at least one of said core dopant varies continuously in a radial direction over the entire core region; the optical fiber having, at a wavelength of 1550 nm, a spontaneous Brillouin spectrum width equal to or larger than 100 MHz, wherein the power fraction is proportional to the first derivative of the radial germanium concentration, ⅆ ⅆ r ⁢ ( Ge ⁡ ( r ) = const * P ⁡ ( r ) wherein Ge(r)=germanium concentration in fiber at radial position r, and P(r)=power in fiber at radial position r.