| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical waveguide which allows incidence of high power excitating light and an optical direct amplifier using the optical waveguide. SOLUTION: An optical waveguide 20 comprises a core part 2 in which a rare earth element is added, a clad part 21 of density lower than the core part 2, and a clad part 22 of density lower than the clad part 21, while an end surface of the clad part 21 is cut obliquely by 45 deg. to form a cut surface 23. A condenser 31 condenses the light emitted from an excitating light source 30, which is made incident on the cut surface 23 from a side surface of the optical waveguide 20 as excitating light 32. A dichroic mirror 25 reflects only the light having the same wavelength as the excitating light 32 out of the light incident on the cut surface 23, which is allowed to propagate in the clad part 21 to excite the rare earth element of the core part 2. A condenser 33 condenses pulse light 6 generated by a signal light source 5, which is made incident on the end surface of the core part 2 from the dichroic mirror 25 as a signal light 34. The incident signal light 34 is amplified optically by the core part 2 to provide an output light 10. |
