| 摘要 |
PURPOSE:To produce optical fiber doped with F at a high production speed by forming a quartz glass layer, doped with F or a F cpd., inside a base material glass tube by means of high frequency induction heat plasma followed by collapsing and drawing. CONSTITUTION:Ar gas 17 for igniting plasma is first introduced into base material quartz tube 1, and heat resistant, electrically conductive rod 6 made of metal or the like is put into tube 1. By applying high frequency power to work coils 3 from high frequency oscillator 4 high frequency induction heat plasma 5 is generated in tube 1. During this time, tube 1 undergoes return traverse in the axial direction and rotation on the axial core with driving mechanism 2. Next raw material such as CF4 8 for a F cpd., O2 gas 9 and SiCl4 10 are fed into tube 1 to form glassy SiO2 contg. SiF4 or other F cpd. inside tube 1. After further laminating this glass layer tube 1 is collapsed by a known method, melted, and drawn to produce step index type optical fiber. |
