| abstract |
PROBLEM TO BE SOLVED: To provide a tellurite glass as a material glass for an optical fiber or an optical waveguide, and to use the tellurite glass, and particularly to provide a wide band optical amplifier which can operate even in a wavelength range of 1.5 μm to 1.7 μm. Medium, an optical amplifier and laser device using the optical amplifying medium and having a wide band and low noise characteristics, a non-quartz optical fiber and a silica optical fiber, or non-quartz optical fibers having different core refractive indices from each other. Provides an optical fiber connection structure for low-loss, low-reflection connection, and a light source. SOLUTION: Tellurite glass is a material glass for an optical fiber or an optical waveguide, and 0 <Bi 2 O 3 ≦ 2. 0 (mol%), 0 ≦ Na 2 O ≦ 35 (mol%), 0 ≦ Z nO ≦ 35 (mol%), and 55 ≦ TeO 2 ≦ 90 (Mol%). |