| 摘要 |
PROBLEM TO BE SOLVED: To enhance beam-condensing efficiency of an optical fiber terminal. SOLUTION: The device is constituted such that, in a single-mode optical fiber 1 having a core for which quartz is doped with germanium or phosphorus and having a clad containing at least quartz, the end of the optical fiber 1 is provided with a core 4 which is expanded towards the tip end of the optical fiber and which is formed in a conical or a ridge shape. Consequently, when a laser beam 9 is emitted from a laser beam source 8 facing oppositely to the surface of the core 4 of the optical fiber terminal, the laser beam 9 expands conically; since the tip end of the optical fiber has the expanded core, the laser beam can be easily converged on the core 4 through a lens effect even if the laser beam is off-centered. |
