Removal of --OH impurities from fiber optic precursor materials
US4310341A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 1980 |
| Grant date | Jan 12, 1982 |
| Priority date | — |
| Expiry date | Sep 12, 2000 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C13/04
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
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 SiCl.sub.4, GeCl.sub.4, POCl.sub.3, and PCl.sub.3. Losses due to --OH impurities occur near various wavelengths of current interest for optical communications systems. Adding chlorine and PCl.sub.3 to impure SiCl.sub.4, GeCl.sub.4, or POCl.sub.3 reduces the amount of --OH impurities and produces POCl.sub.3 and HCl. The HCl may be readily removed, while the POCl.sub.3 is typically left in the material. Bromine may be used instead of chlorine, and PBr.sub.3 may be used instead of PCl.sub.3. In addition, --OH impurities in PCl.sub.3 may be removed by the addition of chlorine or bromine, with the resulting HCl or HBr typically being removed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.