Patent ID: 8687936

Claim:
A silica glass optical fiber comprising: a core including the center axis; an optical cladding surrounding the core; and a jacket surrounding the optical cladding, wherein the core contains GeO 2 , a relative refractive index difference Î”core of the core is greater than or equal to 0.2% and less than or equal to 0.32%, and a refractive index volume v of the core is greater than or equal to 9%Â·Î¼m 2 and less than or equal to 18%Â·Î¼m 2 , the refractive index volume v being expressed by Eq. (1) v= 2âˆ« 0 Î± Î”( r )Â· rÂ·dr (1) where Î”(r) denotes the relative refractive index difference at a radial coordinate r and Î± denotes the diameter of the core, wherein the jacket has a relative refractive index difference Î”J greater than or equal to 0.03% and less than or equal to 0.20%, wherein glass constituting the core has a fictive temperature greater than or equal to 1400Â° C. and less than or equal to 1560Â° C., wherein stress remaining in the core is compressive stress, wherein a cutoff wavelength measured on a fiber having a length of 2 m is greater than or equal to 1300 nm, wherein a cutoff wavelength measured on a fiber having a length of 100 m is less than or equal to 1500 nm, wherein an effective area at a wavelength of 1550 nm is greater than or equal to 110 Î¼m 2 , and wherein a attenuation at a wavelength of 1550 nm is less than or equal to 0.19 dB/km.