Patent ID: 6915053

Claim:
An optical fiber comprising: a core region and a plurality of cladding regions, a first cladding region surrounding the core region, and a (k+1)-th cladding region surrounding a k-th cladding region (k=1, 2, . . . ), wherein the first and the third cladding regions have a plurality of sub medium regions distributed in a main medium; the sub medium has a lower refractive index than the main medium, the core, the k-th cladding regions (k=1, 2, 3), and the sub medium regions extend along the fiber length; the average refractive indices of the core region N[ 0 ], and the k-th cladding regions N[k] (k=1, 2, 3) satisfies N[ 0 ]>N[ 1 ]<N[ 2 ]>N[ 3 ]; and the chromatic dispersion D(λ) and the effective core area A eff (λ) of the fundamental mode satisfy max λ ∈ Ω ⁢ { D ⁡ ( λ ) } - min λ ∈ Ω ⁢ { D ⁡ ( λ ) } < 10 ⁡ [ ps ⁢ / ⁢ nm ⁢ / ⁢ km ] , max λ ∈ Ω ⁢ { D ⁡ ( λ ) } < 20 ⁡ [ ps ⁢ / ⁢ nm ⁢ / ⁢ km ] , and ⁢ ⁢ min λ ∈ Ω ⁢ { A eff ⁡ ( λ ) } < 5 ⁡ [ μm 2 ] , in a wavelength range Ω={λ|λ 1 <=λ<=λ 2 }, where λ 1 >=1200 [nm], λ 2 <=1700 [nm], and λ 2 −λ 1 >=100 [nm].