Patent ID: 9279935
Filing Date: 2016-03-08
CPC Classification: C03B,G02B

Claim Text:
1. A single-mode transmission optical fibre comprising: a central core region radially outwardly from a centerline to a radius r a first inner cladding region extending radially outwardly from the central core to a radius r a second inner cladding region extending radially outwardly from the first inner cladding region to a radius r an intermediate cladding region extending radially outwardly from the second inner cladding region to a radius r an outer cladding region extending radially outwardly from the intermediate cladding region and having a non-negative relative refractive index Δ wherein the relative refractive index Δ 2 of the first inner cladding region is −0.1·10 −3 to −1.0·10 −3 , the relative refractive index Δ 3 of the second inner cladding region is 0 to 0.5·10 −3 , and the relative refractive index Δ 4 of the intermediate cladding is −3.0·10 −3 to −5.0·10 −3 , and wherein the radial width of the intermediate cladding region, defined as a difference (r 4 −r 3 ), is from 8 μm to 22 μm.