| 摘要 |
PROBLEM TO BE SOLVED: To provide with a simple constitution an optical amplifier which suppresses the leakage of inner oscillation light. SOLUTION: In an optical amplifier having rare-earth added light fibers 1a and 1b which are excited by excitation light and amplify light and a feedback means feeding back the light of a prescribed wavelength band in amplified light to the rare-earth added light fibers 1a and 1b, a filter 9 for attenuating the light of the wavelength band is inserted into the rare-earth added light fibers 1a and 1b. |
