| 摘要 |
An optical fiber includes a central glass core region comprising maximum refractive index delta percentΔ1, a first inner annular region surrounding said core comprising refractive index delta percentΔ2, a depressed annular region surrounding said inner annular region and comprisingΔ3 and a third annular region surrounding the depressed annular region comprising refractive index delta percentΔ4; wherein the third annular region comprises chlorine an amount greater than 0.2 weight percent in a region which is within 5 microns from the depressed annular region, whereinΔ1MAX>Δ4>Δ2>Δ3. The difference betweenΔ4 andΔ2 is greater than 0.01 and profile volume, |V3| is at least 50%Δμm2. |
