| 摘要 |
PURPOSE:To form an optical fiber preform having low transmission loss by adding a gas obtained by heating and evaporating a beta-diketone complex of a rare earth metal ion expressed by a specific formula to a reaction atmosphere of a beta-diketone complex of a metal with an F-containing gas. CONSTITUTION:Fluoride glass raw materials such as beta-diketone complexes of Zr, Ba, La, Y, Al, Li and Na filled in stainless steel bubblers 2 placed in individual thermostatic chambers 1 and a beta-diketone complex of a rare earth metal ion such as Pr expressed by the formula (R and R' are 1-7C alkyl or fluoroalkyl; M is rare earth element; (n) is coordination number) are evaporated by heating. The vapors are mixed with an F-containing gas such as SF6 in a mixing chamber 4 and introduced into an evacuated fluoride glass support tube 7. An Ar plasma 6 is generated in the fluoride glass support tube 7 by microwave supplied from a coaxial cable 8 to effect the growth of a glass layer and obtain a fluoride optical fiber preform having low transmission loss. |
