| 摘要 |
PURPOSE:When optical fiber is produced through the MCVD process, the clad part is made from P2O5-F-GeO2-SiO2 glass to give long fibers with very low optical loss in the wave-length zone of longer than 1.3mum. CONSTITUTION:The glass composition of the clad part is made P2O5-F-GeO2-SiO2. As an F-source, is used SiF4, CF4 or SF6. P2O5 mainly lowers the deposition temperature and F reduces the refrative index. GeO2 compensates excessive reduction in refractive index caused by F. Thus, the refractive index of the clad is readily adjusted to 1.458, equal to that of SiO2, in spite of the deposition point of about 1,400 deg.C, such a small amount of P2O5 as the loss in infrared rays characteristically caused by P2O5 can be ignored, and a small amount of SF6 that can stably control the flow rate. Further, since the deposition temperature is low, long fibers are obtained without deformation and the absorption loss intrinsic to the dopant is not caused. |
