Patent ID: 7849713

Claim:
A method for manufacturing a non-zero dispersion optical fibre comprising the steps of: forming a glass preform from which an optical fibre can be drawn, the preform having a core and an outer cladding surrounding the core; heating a region of the preform to permit drawing an optical fibre therefrom; and drawing the preform into the optical fibre by applying a drawing tension to the heated region of the preform, the tension being not greater than 150 g, wherein the drawn optical fibre comprises a central segment, a first annular segment, a second annular segment, an inner cladding segment, and an outer cladding segment, arranged in a sequence in a radial direction of the optical fibre, the central segment having a maximum refractive index percent difference Δ 0 %, the first annular segment having a maximum refractive index percent difference Δ 1 %, the second annular segment having a maximum refractive index percent difference Δ 2 %, the inner cladding segment having a maximum refractive index percent difference Δ 3 %, each of the maximum refractive index percent differences Δ 0 %, Δ 1 %, Δ 2 %, and Δ 3 % being defined with respect to the outer cladding segment, and wherein Δ 0 %>Δ 2 %>Δ 1 %≧0 and Δ 2 %>Δ 3 %≧0, where Δ 0 % is between 0.64% and 0.80%, and the second annular segment has a centre radius r 2 in the range of 5.5 to 7.5 μm, and a width w 2 in the range of 1.7 to 3.0 μm.