| 摘要 |
The presence of hydroxyl impurities (-OH) in optical fiber precursor materials produces optical losses in fibers made from the precursor material, as in the modified chemical vapor deposition process. Typical precursor materials include SiCl4, GeCl4, POCl3, and PCl3. Losses due to -OH impurities occur near various wavelengths of current interest for optical communications systems. Adding chlorine and PCl3 to impure SiCl4, GeCl4, or POCl3 reduces the amount of -OH impurities and produces POCl3 and HCl. The HCl may be readily removed, while the POCl3 is typically left in the material. Bromine may be used instead of chlorine, and PBr3 may be used instead of PCl3. In addition, -OH impurities in PCl3 may be removed by the addition of chlorine or bromine, with the resulting HCl or HBr typically being removed. |
