| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an optical fiber having an extremely low transmission loss. <P>SOLUTION: The optical fiber includes a center core part, a clad layer which is formed on the outer periphery of the center core part and has a refractive index lower than that of the center core part, and a tension bearing clad layer which is formed on the outer periphery of the clad layer and has a refractive index equal to or above that of the center core part. The center core part has a relative refractive index differenceΔ1 of -0.1-0% to pure silica glass, and has a chlorine concentration of 0-0.10 mass% and a fluorine concentration of 0.10-0.30 mass%. The tension bearing clad layer has a relative refractive index differenceΔ4 of 0-0.05% to pure silica glass, has a chlorine concentration≤0.15 mass%, and has a ratio of its outer diameter to the outer diameter of the clad layer set to 1.10-1.40. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
