| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high refractive index glass fiber in which clad mode can be removed quickly by arranging a layer containing a material for absorbing a light of specified wavelength on the outside of a clad layer. SOLUTION: A core 10 is composed of 70Te-10Zn-10Ba-10Na and added with Er. A clad 12 is composed of 55Te-7Ge-10Zn-10Ba-18Na. An absorption layer 14 has same glass composition as the core 10 but Pr is added by 10,000 ppm. The core 10, the clad 12 and the absorption layer 14 have refractive indexes of 1.96, 1.93 and 1.96, respectively. Since the absorption layer 14 has higher refractive index than the clad 12, light propagates quickly from the clad 12 to the absorption layer 14. When the absorption layer 14 is arranged on the outside of the clad layer, clad mode can be removed efficiently. |
