Patent ID: 7203408

Claim:
An optical fibre having an NA-value of less than 0.34, which optical fibre is built up of a core, a cladding, and an enveloping protective coating, wherein the protective coating forms the outer layer of the optical fibre with the overall external diameter of the optical fibre corresponding to the internal diameter of an element into which the end of the optical fibre is inserted; wherein the optical fibre has an overall external diameter in the 120–130 μm range; wherein the protective coating is built up plural sublayers, which sublayers have mutually different E-modulus values; and further comprising an inner sublayer, in direct contact with the cladding, and an outer sublayer, wherein an E-modulus value of the inner sublayer is from 0.5 to 7 MPa, and an E-modulus value of the outer sublayer is from 25 to 1500 MPa.