| 摘要 |
PURPOSE:To provide a fiber laser medium composed mainly of a ZrF4-BaF2-LaF3 fluoride glass and containing U in the core part, directly connectable with a fiber for infrared light and useful as a light-emitting element for optical fiber and emitting light having a wavelength causing low transmission loss in the optical fiber. CONSTITUTION:ZrF4, BaF2, LaF3 and optionally HfF4, LiF, NaF, AlF3 and UF3 are used as raw materials for core and clad and mixed with each other at prescribed ratios. Each mixture for core and clad is added with 1/2pts.wt. of NH4HF2 based on 1pt.wt. of the total weight of the mixture, thrown into a gold crucible and melted at about 900 deg.C for about 90min in Ar gas atmosphere. The molten mixture is cooled to 650 deg.C, the liquid for clad is poured into a mold, the mold is turned upside down to discharge the unsolidified center part and the liquid for core is poured into the formed cavity to obtain a fiber preform. The preform is drawn in the form of a fiber having a diameter equal to the core diameter of the optical fiber to be connected to a fiber laser. The titled medium containing U in the state of U<3+> in the core part and composed mainly of a ZrF4-BaF2-LaF3 fluoride glass can be produced by this process. |
