| 摘要 |
PURPOSE:To obtain a preform giving a rare earth dope fiber capable of obtaining high gain in wide wavelength range by forming soot-like core glass on the inner wall of a quartz reaction tube and successively impregnating a rare earth element compound and an Al compound into the core glass, and then heating the core glass to carry out collapse. CONSTITUTION:Oxide glass fine powder is deposited in a quartz reaction tube 14 by a vapor phase reaction and vitrified by heating using a burner 16 to form a clad glass film 30. Then, shoot-like core glass 32 is similarly formed on the clad glass film 30. A solution dissolving a rate earth element compound (e.g. ErCl3.6H2O) as a solute is fed from a feed tube 28 to the core glass 32 to impregnate the solution into soot-like core glass 32 and the core glass 32 is heated to evaporate the solvent. Then, a solution dissolving an Al compound (e.g. AlCl3) as a solute is fed thereon to again impregnate the solution into the core glass 32 and the solvent is evaporated at ordinary temperature. The quartz reaction tube 14 is subjected to collapse treatment by heating the tube 14 with the burner 16 to provide the preform for rare earth doped fiber. |
