| 摘要 |
PURPOSE:To obtain an optical fiber amplifier capable of securing reliability by a method wherein an exciting light source has a redundancy structure that is the same as the case where the redundancy structure does not exist. CONSTITUTION:A first erbium dope light fiber amplifier 311 is connected in series with a second erbium dope light fiber amplifier 313 via an optical isolator 12. Excited beams by two exciting light sources 34, 34 are inputted from each input side of a 2-input 2-output light branch 33. The excited beams outputted from two output sides are inputted into a first wavelength division multiple coupler 141 of the first erbium dope light fiber amplifier 311 and a second wavelength division multiple coupler 142 of the second erbium dope light fiber amplifier 312. A branch ratio is not uniform and an exciting light source part can be controlled so that the same gain an be obtained even if parts structuring an optical fiber amplifier are not unified. |
