| 摘要 |
PURPOSE: To provide a waveguide for a small-sized high-gain optical amplifier having a high gain and high reliability and its manufacture. CONSTITUTION: In a waveguide for a high-gain optical amplifier with a lower SiO2 clad layer 11 having a low refractive index, a high refractive-index core 12 with a specific section 12a formed on the clad layer 11 and added a rare earth element, and an upper SiO2 clad layer 13 covering the core 12, only the specific section 12a, added the rare earth element, in the core 12 is composed of a phosphoric acid material. A section which the rare earth element is not added in the core 1 is constituted of a material having an SixOyNz composition, and formed in laminated structure. |
