| 摘要 |
The disclosed method of making a mixed glass optical fiber exemplarily comprises providing a high-silica tube, and causing molten non-high silica glass to flow into the bore (12) of the tube by application of a pressure differential. In order to prevent cracking, the tube desirably has an outer diameter/inner diameter ratio of at least 5, preferably about 10 or even more, and an inner diameter of at most 1 mm. In a preferred embodiment, a conventional SiO2 tube is partially collapsed to an inner diameter less than 1 mm, a quantity of a non-high-silica glass is placed in a neck of the partially collapsed tube and heated such that molten glass communicates with the reduced-diameter portion of the bore and can be drawn into the reduced-diameter portion by means of a vacuum. The resulting mixed glass body is then further stretched to result in a core rod of core diameter at most 0.3 mm. After overcladding the core rod with SiO2, fiber is drawn from the thus produced preform. A thus produced fiber with SiO2 cladding and SiO2-Al2O3-La2O3-Er2O3 core was used as an optical fiber amplifier and provided high gain. |
