| 摘要 |
PURPOSE:To effectively utilize a pumping light from a pumping light source of an amplifier and to improve amplifying efficiency by passing the pumping light plural times through an optical fiber doped with a rare earth element. CONSTITUTION:A pumping light emitted from a pumping LD 38 is incident to an optical fiber 10 doped with erbium (Er). On the other hand, a signal light is incident through an incident side optical fiber 12. The signal light is incident to the fiber 10 through a reflection film 40. Er atoms of excited state by the introduction of a pumping light are transited to a low energy state by the introduction of the signal light, and a light is inductively emitter. Thus, the signal light is amplified, and introduced into an emitting side optical fiber 14. On the other hand, the pumping light passed through the fiber 10 is reflected by the film 40, and sent back to the fiber 10, thereby performing further amplifying action. |
