Patent ID: 7689093

Claim:
A single mode optical transmission fiber, comprising: a depressed core having at least 0.41 weight percent of fluorine and an absolute refractive index difference (|Δn 1 |) with pure silica greater than 1.5×10 −3 ; and a depressed cladding having at least 1.2 weight percent of fluorine, an absolute refractive index difference (|Δn 2 |) with pure silica greater than 4.5×10 −3 , and an absolute refractive index difference (|Δn 2 |−|Δn 1 |) with the core greater than 3×10 −3 ; wherein, at a wavelength of 1310 nanometers, the fiber has incremental attenuation of less than 20 dB/km after being subjected to radiation of 10,000 Gy for one hour.