| 摘要 |
PURPOSE:To produce a light-amplifying optical fiber preform having uniform concentrations of rare earth element and Al in longitudinal direction. CONSTITUTION:A GeO3-SiO2 porous glass preform is prepared by a VAD process and immersed in an ethanol solution containing ErCl3 and Al2O3 at prescribed concentrations as salutes. The solution is circulated during the immersion of the porous glass preform in the solution and the concentration of the solution is measured and, when the measured result is different from a preset level, the solution is replenished with a fresh solution having controlled concentration to constantly keep the concentration of the solution. The porous glass preform containing the solution impregnated in the preform is dried, dehydrated and converted to a transparent glass to form an Er-Al2O3-GeO3-SiO2 core preform. |
