Patent ID: 6175680
Filing Date: 2001-01-16
Classification: G02B

Abstract:
A dispersion shifted optical fiber comprising a first core (refractive index n.sub.1), a second core (refractive index n.sub.2), a first clad (refractive index n.sub.3) and a second clad (refractive index n.sub.4) in the order from the center to outside, wherein said refractive indexes are in a relative relationship of n.sub.1 >n.sub.4 >n.sub.2 >n.sub.3, the first core being doped with Ge which is at a ratio of substantially about 0.4 to 1.0% to provide the relative refractive index difference between the second clad and said first core, the second core being doped with F which is at a ratio of substantially about 0.1 to 0.5% to provide the relative refractive index difference between the second clad and the second core, said second cladding being SiO.sub.2, which has a thickness from substantially about 1 .mu.m or more to 40 .mu.m, and F is doped on only the second core of the first core and the second core.