| 摘要 |
PURPOSE:To obtain an optical fiber capable of transmitting infrared ray having a wavelength of 2-6mum, by heating a fluoride glass rod in a molten Al compound, etc. at a temperature below the deformation temperature of the rod, thereby forming a clad structure. CONSTITUTION:A rod of a fluoride glass having higher refractive index than AlF3, LiF and NaF is prepared. The fluoride glass rod is heated in molten Al, compound or in a solution containing at least one of the Al, Li and Na compounds as a solute at a temperature below the deformation temperature of the fluoride glass rod. The ion exchange between the cations constituting said rod and Al<3+>, Li<+> or Na<+> takes place by the process, resulting in the lowering of the refractive index at the circumferential part of the glass rod, and the formation of the clad structure. |
